148 research outputs found

    Unique gene structure and paralogy define the 7D-cadherin family

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    Cadherins are Ca2+-dependent transmembrane glycoproteins crucial for cell-cell adhesion in vertebrates and invertebrates. Classification of this superfamily due to their phylogenetic relationship is currently restricted to three major subfamilies: classical, desmosomal and protocadherins. Here we report evidence for a common phylogenetic origin of the kidney-specific Ksp- (Cdh16) and the intestine-specific LI-cadherin (Cdh17). Both genes consist of 18 exons and the positions of their exon-intron boundaries as well as their intron phases are perfectly conserved. We found an extensive paralogy of more than 40 megabases in mammals as well as teleost fish species encompassing the Ksp- and LI-cadherin genes. A comparable paralogy was not detected for other cadherin gene loci. These findings suggest that the Ksp- and LI-cadherin genes originated by chromosomal duplication early during vertebrate evolution and support our assumption that both proteins are paralogues within a separate cadherin family that we have termed 7D-cadherins

    Einflüsse des Ackerbohnenkäfers (Bruchus rufimanus) und von Bodenpathogenen auf Feldaufgang und Ertrag bei bunt- und weißblühenden Ackerbohnensorten (Vicia faba)

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    We compared field emergence and yield of a white- and a coloured-flowered variety of faba bean (Vicia faba) in relation to Bruchus rufimanus seed damage in a factorial, hand sown mini-plot field experiment. Further manipulating factors at sowing were, foot root rot inoculation with a 4-species Fusarium-mixture, a seed dressing with powdered testa material of the coloured-flower variety and sowing depth. In both varieties Fusarium-inoculation was the most detrimental and significant factor to field emergence and yield, interacting with a concordant B. rufimanus effect. Expectedly, the white-flowered variety was most affected. Tannin-containing testa meal did not reduce or compensate the impact of fungal inoculation and/or B. rufimanus. We hypothesize that B. rufimanus testa damage affects seedling vigour via reported faster water imbibition, causing cellular rupture and higher solute leakage which may enhance soilborne foot root rot incidence and finally yield. The results are discussed in the context of future research objectives

    A novel, non-invasive, online-monitoring, versatile and easy plant-based probe for measuring leaf water status

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    A high-precision pressure probe is described which allows non-invasive online-monitoring of the water relations of intact leaves. Real-time recording of the leaf water status occurred by data transfer to an Internet server. The leaf patch clamp pressure probe measures the attenuated pressure, Pp, of a leaf patch in response to a constant clamp pressure, Pclamp. Pp is sensed by a miniaturized silicone pressure sensor integrated into the device. The magnitude of Pp is dictated by the transfer function of the leaf, Tf, which is a function of leaf patch volume and ultimately of cell turgor pressure, Pc, as shown theoretically. The power function Tf=f(Pc) theoretically derived was experimentally confirmed by concomitant Pp and Pc measurements on intact leaflets of the liana Tetrastigma voinierianum under greenhouse conditions. Simultaneous Pp recordings on leaflets up to 10 m height above ground demonstrated that changes in Tf induced by Pc changes due to changes of microclimate and/or of the irrigation regime were sensitively reflected in corresponding changes of Pp. Analysis of the data show that transpirational water loss during the morning hours was associated with a transient rise in turgor pressure gradients within the leaflets. Subsequent recovery of turgescence during the afternoon was much faster than the preceding transpiration-induced water loss if the plants were well irrigated. Our data show the enormous potential of the leaf patch clamp pressure probe for leaf water studies including unravelling of the hydraulic communication between neighbouring leaves and over long distances within tall plants (trees)

    Worms take to the slo lane: a perspective on the mode of action of emodepside

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    The cyclo-octapdepsipeptide anthelmintic emodepside exerts a profound paralysis on parasitic and free-living nematodes. The neuromuscular junction is a significant determinant of this effect. Pharmacological and electrophysiological analyses in the parasitic nematode Ascaris suum have resolved that emodepside elicits a hyperpolarisation of body wall muscle, which is dependent on extracellular calcium and the efflux of potassium ions. The molecular basis for emodepside’s action has been investigated in forward genetic screens in the free-living nematode Caenorhabditis elegans. Two screens for emodepside resistance, totalling 20,000 genomes, identified several mutants of slo-1, which encodes a calcium-activated potassium channel homologous to mammalian BK channels. Slo-1 null mutants are more than 1000-fold less sensitive to emodepside than wild-type C. elegans and tissue-specific expression studies show emodepside acts on SLO-1 in neurons regulating feeding and motility as well as acting on SLO-1 in body wall muscle. These genetic data, combined with physiological measurements in C. elegans and the earlier physiological analyses on A. suum, define a pivotal role for SLO-1 in the mode of action of emodepside. Additional signalling pathways have emerged as determinants of emodepside’s mode of action through biochemical and hypothesis-driven approaches. Mutant analyses of these pathways suggest a modulatory role for each of them in emodepside’s mode of action; however, they impart much more modest changes in the sensitivity to emodepside than mutations in slo-1. Taken together these studies identify SLO-1 as the major determinant of emodepside’s anthelmintic activity. Structural information on the BK channels has advanced significantly in the last 2 years. Therefore, we rationalise this possibility by suggesting a model that speculates on the nature of the emodepside pharmacophore within the calcium-activated potassium channels

    Search for additional heavy neutral Higgs and gauge bosons in the ditau final state produced in 36 fb−1 of pp collisions at √s=13 TeV with the ATLAS detector

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    A search for heavy neutral Higgs bosons and Z′ bosons is performed using a data sample corresponding to an integrated luminosity of 36.1 fb−1 from proton-proton collisions at √s=13 TeV recorded by the ATLAS detector at the LHC during 2015 and 2016. The heavy resonance is assumed to decay to τ+τ− with at least one tau lepton decaying to final states with hadrons and a neutrino. The search is performed in the mass range of 0.2-2.25 TeV for Higgs bosons and 0.2-4.0 TeV for Z′ bosons. The data are in good agreement with the background predicted by the Standard Model. The results are interpreted in benchmark scenarios. In the context of the hMSSM scenario, the data exclude tan β > 1.0 for mA= 0.25 TeV and tan β > 42 for mA=1.5 TeV at the 95% confidence level. For the Sequential Standard Model, ZSSM′ with mZ′< 2.42 TeV is excluded at 95% confidence level, while Z NU′ with mZ ′ < 2.25 TeV is excluded for the non-universal G(221) model that exhibits enhanced couplings to third-generation fermions

    Search for doubly charged Higgs boson production in multi-lepton final states with the ATLAS detector using proton-proton collisions at √s = 13TeV

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    A search for doubly charged Higgs bosons with pairs of prompt, isolated, highly energetic leptons with the same electric charge is presented. The search uses a proton–proton collision data sample at a centre-of-mass energy of 13 TeV corresponding to 36.1 fb −1 of integrated luminosity recorded in 2015 and 2016 by the ATLAS detector at the LHC. This analysis focuses on the decays H±±→e±e±, H±±→e±μ± and H±±→μ±μ±, fitting the dilepton mass spectra in several exclusive signal regions. No significant evidence of a signal is observed and corresponding limits on the production cross-section and consequently a lower limit on m(H±±) are derived at 95% confidence level. With ℓ±ℓ±=e±e±/μ±μ±/e±μ±, the observed lower limit on the mass of a doubly charged Higgs boson only coupling to left-handed leptons varies from 770 to 870 GeV (850 GeV expected) for B(H±±→ℓ±ℓ±)=100% and both the expected and observed mass limits are above 450 GeV for B(H±±→ℓ±ℓ±)=10% and any combination of partial branching ratios

    Search for photonic signatures of gauge-mediated supersymmetry in 13 TeV pp collisions with the ATLAS detector

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    A search is presented for photonic signatures, motivated by generalized models of gauge-mediated supersymmetry breaking. This search makes use of proton-proton collision data at √s = 13 TeV corresponding to an integrated luminosity of 36.1 fb −1 recorded by the ATLAS detector at the LHC, and it explores models dominated by both strong and electroweak production of supersymmetric partner states. Experimental signatures incorporating an isolated photon and significant missing transverse momentum are explored. These signatures include events with an additional photon or additional jet activity not associated with any specific underlying quark flavor. No significant excess of events is observed above the Standard Model prediction, and 95% confidence-level upper limits of between 0.083 fb and 0.32 fb are set on the visible cross section of contributions from physics beyond the Standard Model. These results are interpreted in terms of lower limits on the masses of gluinos, squarks, and gauginos in the context of generalized models of gauge-mediated supersymmetry, which reach as high as 2.3 TeV for strongly produced and 1.3 TeV for weakly produced supersymmetric partner pairs

    Measurement of differential cross-sections of a top quark produced in association with a W boson at √s=13 TeV with ATLAS

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    The differential cross-section for the production of a W boson in association with a top quark is measured for several particle-level observables. The measurements are performed using 36.1fb−1 of pp collision data collected with the ATLAS detector at the LHC in 2015 and 2016. Differential cross-sections are measured in a fiducial phase space defined by the presence of two charged leptons and exactly one jet matched to a b-hadron, and are normalised with the fiducial cross-section. Results are found to be in good agreement with predictions from several Monte Carlo event generators

    Measurement of the Higgs boson coupling properties in the H → ZZ* → 4 decay channel at √s = 13 TeV with the ATLAS detector

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    The coupling properties of the Higgs boson are studied in the four-lepton (e, μ) decay channel using 36.1 fb−1 of pp collision data from the LHC at a centre-of-mass energy of 13 TeV collected by the ATLAS detector. Cross sections are measured for the main production modes in several exclusive regions of the Higgs boson production phase space and are interpreted in terms of coupling modifiers. The inclusive cross section times branching ratio for H → ZZ∗ decay and for a Higgs boson absolute rapidity below 2.5 is measured to be 1. 73 − 0.23 + 0.24 (stat.) − 0.08 + 0.10 (exp.) ± 0.04(th.) pb compared to the Standard Model prediction of 1.34±0.09 pb. In addition, the tensor structure of the Higgs boson couplings is studied using an effective Lagrangian approach for the description of interactions beyond the Standard Model. Constraints are placed on the non-Standard-Model CP-even and CP-odd couplings to Z bosons and on the CP-odd coupling to gluons

    Search for W W/W Z resonance production in ℓνqq final states in pp collisions at √s=13 TeV with the ATLAS detector

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    A search is conducted for new resonances decaying into a W W or W Z boson pair, where one W boson decays leptonically and the other W or Z boson decays hadronically. It is based on proton-proton collision data with an integrated luminosity of 36.1 fb −1 collected with the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy of s=13 TeV in 2015 and 2016. The search is sensitive to diboson resonance production via vector-boson fusion as well as quark-antiquark annihilation and gluon-gluon fusion mechanisms. No significant excess of events is observed with respect to the Standard Model backgrounds. Several benchmark models are used to interpret the results. Limits on the production cross section are set for a new narrow scalar resonance, a new heavy vector-boson and a spin-2 Kaluza-Klein graviton.[Figure not available: see fulltext.]
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