Long-term thermal sensitivity of Earth’s tropical forests

The sensitivity of tropical forest carbon to climate is a key uncertainty in predicting global climate change. Although short-term drying and warming are known to affect forests, it is unknown if such effects translate into long-term responses. Here, we analyze 590 permanent plots measured across the tropics to derive the equilibrium climate controls on forest carbon. Maximum temperature is the most important predictor of aboveground biomass (−9.1 megagrams of carbon per hectare per degree Celsius), primarily by reducing woody productivity, and has a greater impact per °C in the hottest forests (>32.2°C). Our results nevertheless reveal greater thermal resilience than observations of short-term variation imply. To realize the long-term climate adaptation potential of tropical forests requires both protecting them and stabilizing Earth’s climate

Combinaison des propriétés de soprtion du polydiméthylsiloxane et de phases SPE dans un matériau composite pour l'échantillonnage passif de pesticides polaires et apolaires dans l'eau

International audiencePassive sampling techniques have been developed as an alternative method for in situ integrative monitoring of trace levels of neutral pesticides in environmental waters. The objective of this work was to develop a new receiving phase for pesticides with a wide range of polarities in a single step. We describe the development of three new composite silicone rubbers, combining polydimethylsiloxane mechanical and sorption properties with solid-phase extraction sorbents, prepared as a receiving phase for passive sampling. A composite silicone rubber composed of polydimethylsiloxane/poly(divinylbenzene-co-N-vinylpyrrolidone) was selected by batch experiments for its high sorption properties for pesticides with octanol-water partition coefficients ranging from 2.3 to 5.5. We named this composite material "Polar/Apolar Composite Silicone Rubber". A structural study by scanning electron microscopy confirmed the homogeneous dispersion of the sorbent particles and the encapsulation of particles within the polydimethylsiloxane matrix. We also demonstrate that this composite material is resistant to common solvents used for the back-extraction of analytes and has a maximal resistance temperature of 350°C. Therefore, the characteristics of the "Polar/Apolar Composite Silicone Rubber" meet most of the criteria for use as a receiving phase for the passive sampling of pesticides

NPR1 modulates cross-talk between salicylate- and jasmonate-dependent defense pathways through a novel function in the cytosol

Plant defenses against pathogens and insects are regulated differentially by cross-communicating signal transduction pathways in which salicylic acid (SA) and jasmonic acid (JA) play key roles. In this study, we investigated the molecular mechanism of the antagonistic effect of SA on JA signaling. Arabidopsis plants unable to accumulate SA produced 25-fold higher levels of JA and showed enhanced expression of the JA-responsive genes LOX2, PDF1.2, and VSP in response to infection by Pseudomonas syringae pv tomato DC3000, indicating that in wild-type plants, pathogen-induced SA accumulation is associated with the suppression of JA signaling. Analysis of the Arabidopsis mutant npr1, which is impaired in SA signal transduction, revealed that the antagonistic effect of SA on JA signaling requires the regulatory protein NPR1. Nuclear localization of NPR1, which is essential for SA-mediated defense gene expression, is not required for the suppression of JA signaling, indicating that cross-talk between SA and JA is modulated through a novel function of NPR1 in the cytosol

Serum pepsinogens can help to discriminate between H. pylori-induced and auto-immune atrophic gastritis: Results from a prospective multicenter study

International audienceBackground: Serum pepsinogen (PG) testing is recommended by the European guidelines for diagnosis of chronic atrophic gastritis (CAG). However, wide variations in diagnostic performances are observed, due to the differences in the extent of gastric atrophy, and possibly in its origin (Helicobacter pylori-, autoimmune (AIG)). Aim. To analyze the diagnostic performances of PGs testing according to these different parameters, using enzyme-linked-immunosorbent serologic assay (ELISA) and chemiluminescent immunoassay (CLEIA). Methods: Serum samples from patients having undergone gastroscopy with biopsies in five French centers were collected prospectively. Sensitivity (Se), specificity (Sp), and Area Under Curve were analyzed according to the extent and origin of CAG. Results: Overall, 344 patients (156 males [45%]; mean age 58.8 [±14.2] years) were included, among whom 44 had AIG. Diagnostic performances of PG I for the detection of corpus CAG were excellent, with Se and Sp of 92.7% and 99.1% for ELISA and 90.5% and 98.2% for CLEIA, respectively. For AIG, corresponding values were 97.7% and 97.4% for ELISA, and 95.6% and 97.1% for CLEIA. In multivariate analysis, PG levels were associated with the auto-immune origin (p<0.001) but not with the extent of the atrophic gastritis. Conclusions: Pepsinogens are highly efficient for the diagnosis of corpus-limited CAG and allow to discriminate AIG from H. pylori-induced gastritis

which should be cited to refer to this work. NPR1 Modulates Cross-Talk between Salicylate- and Jasmonate-Dependent Defense Pathways through a Novel Function in the Cytosol

Plant defenses against pathogens and insects are regulated differentially by cross-communicating signal transduction pathways in which salicylic acid (SA) and jasmonic acid (JA) play key roles. In this study, we investigated the molecular mechanism of the antagonistic effect of SA on JA signaling. Arabidopsis plants unable to accumulate SA produced 25-fold higher levels of JA and showed enhanced expression of the JA-responsive genes LOX2, PDF1.2, and VSP in response to infection by Pseudomonas syringae pv tomato DC3000, indicating that in wild-type plants, pathogen-induced SA accumulation is associated with the suppression of JA signaling. Analysis of the Arabidopsis mutant npr1, which is impaired in SA signal transduction, revealed that the antagonistic effect of SA on JA signaling requires the regulatory protein NPR1. Nuclear localization of NPR1, which is essential for SA-mediated defense gene expression, is not required for the suppression of JA signaling, indicating that cross-talk between SA and JA is modulated through a novel function of NPR1 in the cytosol

Spatial Positioning and Matrix Programs of Cancer-Associated Fibroblasts Promote T-cell Exclusion in Human Lung Tumors

International audienceIt is currently accepted that cancer-associated fibroblasts (CAF) participate in T-cell exclusion from tumor nests. To unbiasedly test this, we used single-cell RNA sequencing coupled with multiplex imaging on a large cohort of lung tumors. We identified four main CAF populations, two of which are associated with T-cell exclusion: (i) MYH11+αSMA+ CAF, which are present in early-stage tumors and form a single cell layer lining cancer aggregates, and (ii) FAP+αSMA+ CAF, which appear in more advanced tumors and organize in patches within the stroma or in multiple layers around tumor nests. Both populations orchestrate a particular structural tissue organization through dense and aligned fiber deposition compared with T cell–permissive CAF. Yet they produce distinct matrix molecules, including collagen IV (MYH11+αSMA+ CAF) and collagen XI/XII (FAP+αSMA+ CAF). Hereby, we uncovered unique molecular programs of CAF driving T-cell marginalization, whose targeting should increase immunotherapy efficacy in patients bearing T cell–excluded tumors. SIGNIFICANCE: The cellular and molecular programs driving T-cell marginalization in solid tumors remain unclear. Here, we describe two CAF populations associated with T-cell exclusion in human lung tumors. We demonstrate the importance of pairing molecular and spatial analysis of the tumor micro-environment, a prerequisite to developing new strategies targeting T cell–excluding CAF