European standards for the protection of forests from ozone (O3) are based on atmospheric exposure (AOT40) that is not always representative of O3 effects since it is not a proxy of gas uptake ...through stomata (stomatal flux). MOTTLES “MOnitoring ozone injury for seTTing new critical LEvelS” is a LIFE project aimed at establishing a permanent network of forest sites based on active O3 monitoring at remote areas at high and medium risk of O3 injury, in order to define new standards based on stomatal flux, i.e. PODY (Phytotoxic Ozone Dose above a threshold Y of uptake). Based on the first year of data collected at MOTTLES sites, we describe the MOTTLES monitoring station, together with protocols and metric calculation methods. AOT40 and PODY, computed with different methods, are then compared and correlated with forest–health indicators (radial growth, crown defoliation, visible foliar O3 injury). For the year 2017, the average AOT40 calculated according to the European Directive was even 5 times (on average 1.7 times) the European legislative standard for the protection of forests. When the metrics were calculated according to the European protocols (EU Directive 2008/50/EC or Modelling and Mapping Manual LTRAP Convention), the values were well correlated to those obtained on the basis of the real duration of the growing season (i.e. MOTTLES method) and were thus representative of the actual exposure/flux. AOT40 showed opposite direction relative to PODY. Visible foliar O3 injury appeared as the best forest–health indicator for O3 under field conditions and was more frequently detected at forest edge than inside the forest. The present work may help the set–up of further long–term forest monitoring sites dedicated to O3 assessment in forests, especially because flux-based assessments are recommended as part of monitoring air pollution impacts on ecosystems in the revised EU National Emissions Ceilings Directive.
•The MOTTLES network for active O3 monitoring in forests is described.•In 2017, AOT40 exceeded twice the limit of the European Directive for forests.•O3 metrics from European protocols were representative of actual exposure/fluxes.•AOT40 and PODy were inversely correlated.•Visible foliar injury was the best forest–health indicator for O3.
Emission of BVOC (Biogenic Volatile Organic Compounds) from plant leaves in response to ozone exposure (O3) and nitrogen (N) fertilization is poorly understood. For the first time, BVOC emissions ...were explored in a forest tree species (silver birch, Betula pendula) exposed for two years to realistic levels of O3 (35, 48 and 69 ppb as daylight average) and N (10, 30 and 70 kg ha−1 yr−1, applied weekly to the soil as ammonium nitrate). The main BVOCs emitted were: α-pinene, β-pinene, limonene, ocimene, (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT) and hexanal. Ozone exposure increased BVOC emission and reduced total leaf area. The effect on emission was stronger when a short-term O3 metric (concentrations at the time of sampling) rather than a long-term one (AOT40) was used. The effect of O3 on total leaf area was not able to compensate for the stimulation of emission, so that responses to O3 at leaf and whole-plant level were similar. Nitrogen fertilization increased total leaf area, decreased α-pinene and β-pinene emission, and increased ocimene, hexanal and DMNT emission. The increase of leaf area changed the significance of the emission response to N fertilization for most compounds. Nitrogen fertilization mitigated the effects of O3 exposure on total leaf area, while the combined effects of O3 exposure and N fertilization on BVOC emission were additive and not synergistic. In conclusion, O3 exposure and N fertilization have the potential to affect global BVOC via direct effects on plant emission rates and changes in leaf area.
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•Ozone exposure stimulated BVOC emission.•Responses to an episodic O3 metric were stronger than to a seasonal one.•N fertilization showed compound-specific effects (from inhibition to stimulation).•N-driven changes in total leaf area affected the magnitude of these effects.•O3 and N impacted BVOC emission individually, with no significant interactions.
Ozone exposure increased BVOC emission and reduced total leaf area, while N fertilization increased total leaf area and showed compound-specific effects (from inhibition to stimulation) on BVOC emission.
Tropospheric ozone is a dangerous atmospheric pollutant for forest ecosystems when it penetrates stomata. Thresholds for ozone-risk assessment are based on accumulated stomatal ozone fluxes such as ...the Phytotoxic Ozone Dose (POD). In order to identify the effect of ozone on a Holm oak forest in central Italy, four flux-based ozone impact response functions were implemented and tested in a multi-layer canopy model AIRTREE and evaluated against Gross Primary Productivity (GPP) obtained from observations of Eddy Covariance fluxes of CO2. To evaluate if a clear phytotoxic threshold exists and if it changes during the year, six different detoxifying thresholds ranging between 0 and 5 nmol O3 m−2 s−1 were tested.
The use of species-specific rather than more general response functions based on plant functional types (PFT) increased model accuracy (RMSE reduced by up to 8.5%). In the case of linear response functions, a threshold of 1 nmol m−2 s−2 produced the best results for simulations of the whole year, although the tolerance to ozone changed seasonally, with higher tolerance (5 nmol m−2 s−1 or no ozone impact) for Winter and Spring and lower thresholds in Summer and Fall (0–1 nmol m−2 s−1). A “dynamic threshold” obtained by extracting the best daily threshold values from a range of different simulations helped reduce model overestimation of GPP by 213 g C m−2 y−1 and reduce RMSE up to 7.7%. Finally, a nonlinear ozone correction based on manipulative experiments produced the best results when no detoxifying threshold was applied (0 nmol O3 m−2 s−1), suggesting that nonlinear functions fully account for ozone detoxification. The evidence of seasonal changes in ozone tolerance points to the need for seasonal thresholds to predict ozone damage and highlights the importance of performing more species-specific manipulative experiments to derive response functions for a broad range of plant species.
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•Flux-based ozone impact response functions were implemented in a canopy model.•Both linear and nonlinear ozone response functions led to more realistic simulation.•Seasonal changes in ozone tolerance points to the need for seasonal thresholds.
Stomatal ozone flux is closely related to ozone injury to plants. Jarvis-type multiplicative model has been recommended for estimating stomatal ozone flux in forest trees. Ozone can change stomatal ...conductance by both stomatal closure and less efficient stomatal control (stomatal sluggishness). However, current Jarvis-type models do not account for these ozone effects on stomatal conductance in forest trees. We examined seasonal course of stomatal conductance in two common deciduous tree species native to northern Japan (white birch: Betula platyphylla var. japonica; deciduous oak: Quercus mongolica var. crispula) grown under free-air ozone exposure. We innovatively considered stomatal sluggishness in the Jarvis-type model using a simple parameter, s, relating to cumulative ozone uptake (defined as POD: phytotoxic ozone dose). We found that ozone decreased stomatal conductance of white birch leaves after full expansion (-28%). However, such a reduction of stomatal conductance by ozone fell in late summer (-10%). At the same time, ozone reduced stomatal sensitivity of white birch to VPD and increased stomatal conductance under low light conditions. In contrast, in deciduous oak, ozone did not clearly change the model parameters. The consideration of both ozone-induced stomatal closure and stomatal sluggishness improved the model performance to estimate stomatal conductance and to explain the dose-response relationship on ozone-induced decline of photosynthesis of white birch. Our results indicate that ozone effects on stomatal conductance (i.e. stomatal closure and stomatal sluggishness) are crucial for modelling studies to determine stomatal response in deciduous trees, especially in species sensitive to ozone.
In their natural environment, date palms are exposed to chronic atmospheric ozone (O3) concentrations from local and remote sources. In order to elucidate the consequences of this exposure, date palm ...saplings were treated with ambient, 1.5 and 2.0 times ambient O3 for three months in a free-air controlled exposure facility. Chronic O3 exposure reduced carbohydrate contents in leaves and roots, but this effect was much stronger in roots. Still, sucrose contents of both organs were maintained at elevated O3, though at different steady states. Reduced availability of carbohydrate for the Tricarboxylic acid cycle (TCA cycle) may be responsible for the observed reduced foliar contents of several amino acids, whereas malic acid accumulation in the roots indicates a reduced use of TCA cycle intermediates. Carbohydrate deficiency in roots, but not in leaves caused oxidative stress upon chronic O3 exposure, as indicated by enhanced malonedialdehyde, H2O2 and oxidized glutathione contents despite elevated glutathione reductase activity. Reduced levels of phenolics and flavonoids in the roots resulted from decreased production and, therefore, do not indicate oxidative stress compensation by secondary compounds. These results show that roots of date palms are highly susceptible to chronic O3 exposure as a consequence of carbohydrate deficiency.
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•O3 affects roots rather than leaves as a consequence of strong carbohydrate deficiency.•Sucrose levels still were maintained at the expense of other carbohydrates.•Carbohydrate deficiency in the roots caused oxidative stress.
This is the longest continuous experiment where ethylenediurea (EDU) was used to protect plants from ozone (O3). Effects of long-term ambient O3 exposure (23 ppm h AOT40) on biomass of an O3 ...sensitive poplar clone (Oxford) were examined after six years from in-ground planting. Trees were irrigated with either water or 450 ppm EDU. Above (−51%) and below-ground biomass (−47%) was reduced by O3 although the effect was significant only for stem and coarse roots. Ambient O3 decreased diameter of the lower stem, and increased moisture content along the stem of not-protected plants (+16%). No other change in the physical wood structure was observed. A comparison with a previous assessment in the same experiment suggested that O3 effects on biomass partitioning to above-ground organs depend on the tree ontogenetic stage. The root/shoot ratios did not change, suggesting that previous short-term observations of reduced allocation to tree roots may be overestimated.
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•6-y ambient O3 exposure was investigated in a sensitive poplar clone.•EDU irrigation protected poplar against ambient O3 exposure.•O3 reduced biomass of roots and stem, but did not change biomass allocation.•O3 decreased stem diameter only in the lower third of the stem.•O3 increased moisture content of the wood along the stem.
Ozone exposure reduced lateral branching, leaves and roots in younger trees, and affected stem and roots in older trees, while shoot/root ratios did not change.
A comparison of the maps of stomatal ozone uptake (AFst0) and concentrations exceeding 40 ppb (AOT40) for dominant temperate deciduous tree species (Quercus serrata, Fagus crenata, Betula ermanii) ...was conducted in Japan. Estimations of stomatal ozone uptake were accomplished using estimated ozone concentration, climate data, and vegetation data. Key parameters such as stomatal conductance parameters for each species were collected from scientific literature in Japan. Stomatal closure induced by vapour pressure deficit affected the AFst0 values in warmer part of Japan. For this reason, the areas with high AOT40 did not always correspond to the areas with high AFst0. The result showed that ozone risk assessment using AOT40 is VPD-constrained in central Japan, which implies an overestimation of risk compared to AFst0. While in Europe AOT40 is higher where water stress is recurrent, AOT40 peaked in the cool and humid climate region of central-eastern Japan where also stomatal ozone uptake reached maximum values.
Summary
Background
Familial platelet disorder (FPD) is a rare autosomal dominant disease characterized by thrombocytopenia and abnormal platelet function. Causal mutations have been identified in the ...gene encoding runt‐related transcription factor 1 (RUNX1) of FPD patients.
Objectives
To elucidate the role of RUNX1 in the regulation of expression of platelet factor 4 (PF4) and to propose a plausible mechanism underlying RUNX1‐mediated induction of the FPD phenotype.
Methods
We assessed whether RUNX1 and its mutants, in combination with E26 transformation‐specific‐1 (ETS‐1), Core‐binding factor subunit beta (CBFβ), and Friend leukemia virus integration 1 (FLI‐1), cooperatively regulate PF4 expression during megakaryocytic differentiation. In an embryonic stem cell differentiation system, expression levels of endogenous and exogenous RUNX1 and PF4 were determined by real‐time RT‐PCR. Promoter activation by the transcription factors were evaluated by reporter gene assays with HepG2 cells. DNA binding activity and protein interaction were analyzed by electrophoretic mobility shift assay and immunoprecipitation assay with Cos‐7 cells, respectively. Protein localization was analyzed by immunocytochemistry and Western blotting with Cos‐7 cells.
Results
We demonstrated that RUNX1 activates endogenous PF4 expression in megakaryocytic differentiation. RUNX1, but not its mutants, in combination with ETS‐1 and CBFβ, or FLI‐1, synergistically activated the PF4 promoter. Each RUNX1 mutant harbors various functional abnormalities, including loss of DNA‐binding activity, abnormal subcellular localization, and/or alterations of binding affinities for ETS‐1, CBFβ, and FLI‐1.
Conclusions
RUNX1, but not its mutants, strongly and synergistically activates PF4 expression along with ETS family proteins. Furthermore, loss of the RUNX1 transcriptional activation function is induced by various functional abnormalities.
Abstract
Background
Prevention of heart failure is one of the most important challenges after acute myocardial infarction (AMI). The development of heart failure is closely associated with fluid ...balance which can be evaluated by the measurement of body composition such as total body water (TBW), extracellular water (ECW), and intracellular water (ICW). This subgroup analysis of the EMBODY trial was designed to determine whether the Sodium–glucose cotransporter 2 (SGLT2) inhibitor affect fluid balance and improve heart failure in patients after AMI.
Methods
The EMBODY trial was a prospective, multicenter, randomized, double-blind, placebo-controlled trial in patients with AMI and type 2 diabetes in Japan. A total of 105 patients were randomized (1:1) to receive once-daily 10 mg empagliflozin, an SGLT2 inhibitor or placebo 2 weeks after the onset of AMI. In this subanalysis, we investigated the time-course of body composition measured by a bioelectrical impedance analyzer “InBody®”. The primary endpoints were changes in every particular parameter of body composition at week 0, 4, 12, and 24. Secondary endpoints were changes in blood pressure (BP), body weight and N-terminal pro b-type natriuretic peptide (NT-proBNP).
Results
Overall, 55 patients were included in the full analysis set (67.2±10.0 years, male 78.2%, and n=30 in empagliflozin group and 25 in placebo group). Baseline characteristics were not significantly different between the two groups. The change between at baseline and 24 weeks in TBW was −0.44 L (P=0.19) in the empagliflozin group and +1.14 L (P=0.0002) in the placebo group, adjusted difference −1.58 L, 95% confidence interval (CI) −2.46 to −0.70 L (P=0.0006). The empagliflozin group showed significant decreases in the body weight, ECW, ICW and systolic BP compared with the placebo group (−2.2 kg vs, +0.01 kg, P=0.004, −0.21 L vs, +0.40 L, P=0.001, −0.23 L vs, +0.74 L, P=0.0007, and −11.0 mmHg vs, +5.0 mmHg, P<0.0001, respectively). On the other hand, NT-Pro BNP levels significantly decreased in the empagliflozin group and placebo group (1028.7 pg/mL to 370.3 pg/ml, p=0.0001 and 1270.6 pg/mL to 673.7 pg/ml, p=0.006, respectively). In the multiple regression analysis of the change in TBW and ICW for the empagliflozin group, systolic BP was identified as a significant factor (P=0.001, and 0.003, respectively). In stratified analysis of BMI 25 kg/m2 or more, the empagliflozin group showed significant decreases in body weight, TBW, ECW and ICW compared with the placebo group, but not below BMI 25 kg/m2 group.
Conclusion
Empagliflozin reduced not only body weight, but also TBW, ECW and ICW. Interestingly, this tendency was remarkable at BMI 25 or more. This study suggested that early SGLT2 inhibitor administration in obesity patients with AMI and DM might be effective to reduce body weight and TBW.
Funding Acknowledgement
Type of funding source: Private grant(s) and/or Sponsorship. Main funding source(s): Boehringer Ingelheim
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