4,698 research outputs found

    Generation of Phaseolus vulgaris ESTs and investigation of their regulation upon Uromyces appendiculatus infection

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    <p>Abstract</p> <p>Background</p> <p><it>Phaseolus vulgaris </it>(common bean) is the second most important legume crop in the world after soybean. Consequently, yield losses due to fungal infection, like <it>Uromyces appendiculatus </it>(bean rust), have strong consequences. Several resistant genes were identified that confer resistance to bean rust infection. However, the downstream genes and mechanisms involved in bean resistance to infection are poorly characterized.</p> <p>Results</p> <p>A subtractive bean cDNA library composed of 10,581 unisequences was constructed and enriched in sequences regulated by either bean rust race 41, a virulent strain, or race 49, an avirulent strain on cultivar Early Gallatin carrying the resistance gene <it>Ur-4</it>. The construction of this library allowed the identification of 6,202 new bean ESTs, significantly adding to the available sequences for this plant. Regulation of selected bean genes in response to bean rust infection was confirmed by qRT-PCR. Plant gene expression was similar for both race 41 and 49 during the first 48 hours of the infection process but varied significantly at the later time points (72–96 hours after inoculation) mainly due to the presence of the <it>Avr4 </it>gene in the race 49 leading to a hypersensitive response in the bean plants. A biphasic pattern of gene expression was observed for several genes regulated in response to fungal infection.</p> <p>Conclusion</p> <p>The enrichment of the public database with over 6,000 bean ESTs significantly adds to the genomic resources available for this important crop plant. The analysis of these genes in response to bean rust infection provides a foundation for further studies of the mechanism of fungal disease resistance. The expression pattern of 90 bean genes upon rust infection shares several features with other legumes infected by biotrophic fungi. This finding suggests that the <it>P. vulgaris</it>-<it>U. appendiculatus </it>pathosystem could serve as a model to explore legume-rust interaction.</p

    Case report: Adult-onset limb girdle muscular dystrophy in sibling pair due to novel homozygous LAMA2 missense variant

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    Recessive pathogenic variants in the laminin subunit alpha 2 (LAMA2) gene cause a spectrum of disease ranging from severe congenital muscular dystrophy to later-onset limb girdle muscular dystrophy (LGMDR23). The phenotype of LGMDR23 is characterized by slowly progressive proximal limb weakness, contractures, raised creatine kinase, and sometimes distinctive cerebral white matter changes and/or epilepsy. We present two siblings, born to consanguineous parents, who developed adult-onset LGMDR23 associated with typical cerebral white matter changes and who both later developed dementia. The male proband also had epilepsy and upper motor neuron signs when he presented at age 72. Merosin immunohistochemistry and Western blot on muscle biopsies taken from both subjects was normal. Whole exome sequencing revealed a previously unreported homozygous missense variant in LAMA2 [Chr6(GRCh38):g.129297734G&gt;A; NM_000426.3:c.2906G&gt;A; p.(Cys969Tyr)] in the proband. The same homozygous LAMA2 variant was confirmed by Sanger sequencing in the proband's affected sister. These findings expand the genotypic and phenotypic spectrum of LGMDR23

    Connective tissue presentation in two families expands the phenotypic spectrum of PYROXD1 disorders

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    Recessive variants in the oxidoreductase PYROXD1 are reported to cause a myopathy in 22 affected individuals from 15 families. Here, we describe two female probands from unrelated families presenting with features of a congenital connective tissue disorder including osteopenia, blue sclera, soft skin, joint hypermobility and neuromuscular junction dysfunction in addition to known features of PYROXD1 myopathy including respiratory difficulties, weakness, hypotonia and oromotor dysfunction. Proband AII:1 is compound heterozygous for the recurrent PYROXD1 variant Chr12(GRCh38):g.21452130A\u3eG;NM_024854.5:c.464A\u3eG;p.(N155S) and Chr12(GRCh38):g.21462019_21462022del;NM_024854.5:c.892_895del;p.(V298Mfs*4) and proband BII:1 is compound heterozygous for Chr12(GRCh38):g.21468739-21468741del;NM_024854.5:c.1488_1490del;p.(E496del) and Chr12(GRCh38):g.21467619del;NM_024854.5:c.1254+1del. RNA studies demonstrate c.892_895del;p.(V298Mfs*4) is targeted by nonsense mediated decay and c.1254+1delG elicits in-frame skipping of exon-11. Western blot from cultured fibroblasts shows reduced PYROXD1 protein levels in both probands. Testing urine from BII:1 and six individuals with PYROXD1 myopathy showed elevated levels of deoxypyridinoline, a mature collagen crosslink, correlating with PYROXD1-disorder severity. Urine and serum amino acid testing of the same individuals revealed no reportable changes. In contrast to PYROXD1 knock-out, we find no evidence for disrupted tRNA ligase activity, as measured via XBP1 splicing, in fibroblasts expressing PYROXD1 variants. In summary, we expand the clinical spectrum of PYROXD1-related disorders to include an overlapping connective tissue and myopathy presentation, identify three novel, pathogenic PYROXD1 variants, and provide preliminary evidence that elevated urine DPD crosslinks may provide a clinical biomarker for PYROXD1 disorders. Our results advocate consideration of PYROXD1 variants in the differential diagnosis for undiagnosed individuals presenting with a connective tissue disorder and myopathy

    Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV

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    A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7 TeV is presented. The data were collected at the LHC, with the CMS detector, and correspond to an integrated luminosity of 4.6 inverse femtobarns. No significant excess is observed above the background expectation, and upper limits are set on the Higgs boson production cross section. The presence of the standard model Higgs boson with a mass in the 270-440 GeV range is excluded at 95% confidence level.Comment: Submitted to JHE

    Search for anomalous t t-bar production in the highly-boosted all-hadronic final state

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    A search is presented for a massive particle, generically referred to as a Z', decaying into a t t-bar pair. The search focuses on Z' resonances that are sufficiently massive to produce highly Lorentz-boosted top quarks, which yield collimated decay products that are partially or fully merged into single jets. The analysis uses new methods to analyze jet substructure, providing suppression of the non-top multijet backgrounds. The analysis is based on a data sample of proton-proton collisions at a center-of-mass energy of 7 TeV, corresponding to an integrated luminosity of 5 inverse femtobarns. Upper limits in the range of 1 pb are set on the product of the production cross section and branching fraction for a topcolor Z' modeled for several widths, as well as for a Randall--Sundrum Kaluza--Klein gluon. In addition, the results constrain any enhancement in t t-bar production beyond expectations of the standard model for t t-bar invariant masses larger than 1 TeV.Comment: Submitted to the Journal of High Energy Physics; this version includes a minor typo correction that will be submitted as an erratu

    Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

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    The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum

    Measurement of the t t-bar production cross section in the dilepton channel in pp collisions at sqrt(s) = 7 TeV

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    The t t-bar production cross section (sigma[t t-bar]) is measured in proton-proton collisions at sqrt(s) = 7 TeV in data collected by the CMS experiment, corresponding to an integrated luminosity of 2.3 inverse femtobarns. The measurement is performed in events with two leptons (electrons or muons) in the final state, at least two jets identified as jets originating from b quarks, and the presence of an imbalance in transverse momentum. The measured value of sigma[t t-bar] for a top-quark mass of 172.5 GeV is 161.9 +/- 2.5 (stat.) +5.1/-5.0 (syst.) +/- 3.6(lumi.) pb, consistent with the prediction of the standard model.Comment: Replaced with published version. Included journal reference and DO

    Combined search for the quarks of a sequential fourth generation

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    Results are presented from a search for a fourth generation of quarks produced singly or in pairs in a data set corresponding to an integrated luminosity of 5 inverse femtobarns recorded by the CMS experiment at the LHC in 2011. A novel strategy has been developed for a combined search for quarks of the up and down type in decay channels with at least one isolated muon or electron. Limits on the mass of the fourth-generation quarks and the relevant Cabibbo-Kobayashi-Maskawa matrix elements are derived in the context of a simple extension of the standard model with a sequential fourth generation of fermions. The existence of mass-degenerate fourth-generation quarks with masses below 685 GeV is excluded at 95% confidence level for minimal off-diagonal mixing between the third- and the fourth-generation quarks. With a mass difference of 25 GeV between the quark masses, the obtained limit on the masses of the fourth-generation quarks shifts by about +/- 20 GeV. These results significantly reduce the allowed parameter space for a fourth generation of fermions.Comment: Replaced with published version. Added journal reference and DO
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