Expression profiling during arabidopsis/downy mildew interaction reveals a highly-expressed effector that attenuates responses to salicylic acid

Plants have evolved strong innate immunity mechanisms, but successful pathogens evade or suppress plant immunity via effectors delivered into the plant cell. Hyaloperonospora arabidopsidis (Hpa) causes downy mildew on Arabidopsis thaliana, and a genome sequence is available for isolate Emoy2. Here, we exploit the availability of genome sequences for Hpa and Arabidopsis to measure gene-expression changes in both Hpa and Arabidopsis simultaneously during infection. Using a high-throughput cDNA tag sequencing method, we reveal expression patterns of Hpa predicted effectors and Arabidopsis genes in compatible and incompatible interactions, and promoter elements associated with Hpa genes expressed during infection. By resequencing Hpa isolate Waco9, we found it evades Arabidopsis resistance gene RPP1 through deletion of the cognate recognized effector ATR1. Arabidopsis salicylic acid (SA)-responsive genes including PR1 were activated not only at early time points in the incompatible interaction but also at late time points in the compatible interaction. By histochemical analysis, we found that Hpa suppresses SA-inducible PR1 expression, specifically in the haustoriated cells into which host-translocated effectors are delivered, but not in non-haustoriated adjacent cells. Finally, we found a highly-expressed Hpa effector candidate that suppresses responsiveness to SA. As this approach can be easily applied to host-pathogen interactions for which both host and pathogen genome sequences are available, this work opens the door towards transcriptome studies in infection biology that should help unravel pathogen infection strategies and the mechanisms by which host defense responses are overcome

Residual Stress in Brazing of Submicron Al2O3 to WC-Co

International audienceThis study evaluated the residual stresses induced by brazing and grinding submicron Al2O3, using different methods. Energy dispersive x-ray spectrometry analysis (EDX) of 72Ag-Cu filler and filler/WC-Co interface showed evidence of atomic diffusion and possible formation of titanium oxide layers between the joint and the bonding materials. An analytical model supported by the finite element method (FEM) based on strain determination due to the difference in variation of thermal expansion was used to assess the stress distribution at the coupling interface and in bulk materials. The model took into account the evolution of the Young’s modulus and of the thermal expansion with temperature. The model could be used to follow strain and stress evolutions of the bonded materials during the cooling cycle. The maximum stress rose above −300 MPa at the center of the 100 × 100 × 3 mm ceramic plates. The residual stresses on the external surface of ceramic were investigated by x-ray diffraction (XRD) and indentation fracture method (IFM). After brazing and grinding the plate, the principal stresses were 128.1 and 94.9 MPa, and the shear stress was −20.1 MPa. Microscopic examination revealed grain pull-out promoted by the global residual stresses induced by the brazing and grinding processes. The surface stresses evaluated by the different methods were reasonably correlated

Validation of large scale noise exposure modelling by long-term measurements

Large scale noise exposure modelling is used in epidemiological research projects as well as for noise mapping and strategic action planning. Such calculations should always be accompanied by an assessment of uncertainty, on the one hand to check for systematic deviations and on the other hand to investigate the sources of uncertainty to address them in future studies. Within the SiRENE (Short and Long Term Effects of Transportation Noise Exposure) project, a large scale nationwide assessment of Switzerland’s road, railway, and aircraft noise exposure was conducted for the year 2011. In the present follow-up study, we equipped 180 sleeping and/or living room windows with sound level meters for one week. The resulting dataset was used to validate noise exposure modelling within SiRENE. For the noise metric LDEN the comparison revealed a difference of 1.6 ± 5 dB(A) when taking all measurements into account. After removing measurement sites with noise mitigation measures not considered in the modelling, the difference to the calculation was reduced to 0.5 ± 4 dB(A). As major sources of uncertainty, the position accuracy and topicality of infrastructure and building geometries, the traffic modelling as well as the acoustic source and propagation models were identified

Validation of large scale noise exposure modeling by long-term measurements

Abstract Large scale noise exposure modelling is used in epidemiological research projects as well as for noise mapping and strategic action planning. Such calculations should always be accompanied by an assessment of uncertainty, on the one hand to check for systematic deviations and on the other hand to investigate the sources of uncertainty to address them in future studies. Within the SiRENE (Short and Long Term Effects of Transportation Noise Exposure) project, a large scale nationwide assessment of Switzerland’s road, railway, and aircraft noise exposure was conducted for the year 2011. In the present follow-up study, we equipped 180 sleeping and/or living room windows with sound level meters for one week. The resulting dataset was used to validate noise exposure modelling within SiRENE. For the noise metric LDEN the comparison revealed a difference of 1.6 ± 5 dB(A) when taking all measurements into account. After removing measurement sites with noise mitigation measures not considered in the modelling, the difference to the calculation was reduced to 0.5 ± 4 dB(A). As major sources of uncertainty, the position accuracy and topicality of infrastructure and building geometries, the traffic modelling as well as the acoustic source and propagation models were identified.</jats:p