Modèles agro-environnementaux de la fertilisation phosphatée dans les sols acides de pomme de terre de l'Est du Canada

Le phosphore (P) est indispensable pour la pomme de terre, la principale culture des provinces de l’Est canadien. La diminution des réserves phosphatées et le risque de perte de cet élément dans les cours d’eau constituent des contraintes majeures pour la sécurité alimentaire et pour l’environnement. L’objectif de ce projet de recherche est d’optimiser la dose et le type d’engrais phosphaté en vue de minimiser le risque d’accumulation du P dans le sol, et de substituer les engrais de synthèse par des engrais recyclés. Un total de 141 échantillons représentatifs des sols de l’Île-du-Prince-Édouard (ÎPE) a été d’abord analysé et a montré que l’acidité du sol influait grandement sur le pourcentage de saturation des sols en P. Ainsi, les seuils critiques environnementaux en terme d’indice de saturation en P, (P/Al)M3 ont été de 19% pour les sols très acides (pHeau5,5), au-dessus desquels la fertilisation en P devrait être limitée aux besoins de la culture. Six classes de risque environnemental ont été identifiées et leur répartition spatiale a montré que la classe de risque modéré était prédominante à l’ÎPE. Nous avons ensuite développé un modèle agro-environnemental de P pour la pomme de terre basé sur 42 essais de fertilisation conduits dans les provinces maritimes (ÎPE, Nouveau-Brunswick (NB) et Nouvelle-Écosse (NÉ)). Ce modèle, basé sur l’indice (P/Al)M3, a été composé de sept classes de diagnostic et de recommandation pour la fertilisation phosphatée : (0-2,5%), (2,5%-5%), (5%-10%), (10%-14%), (14%-16%), (16%-23%) et (P/Al)M3>23% correspondant, respectivement, aux doses optimales en P de 105, 81, 70 kg P ha-1 pour les trois premières classes, et à une dose de 21 kg ha-1 pour les classes dont le (P/Al)M3 est supérieur à 10%. Finalement, pour évaluer l’efficacité d’un engrais phosphaté recyclé (Crystal Green®), nous avons conduit 8 essais de fertilisation au Québec et dans les provinces maritimes. Il a été conclu que la fertilisation phosphatée avec le Crystal Green® pourrait substituer le triple superphosphate (TSP) jusqu’à 75% sans que les niveaux de rendements en pomme de terre, le prélèvement du P, et le statut du P dans le sol et dans la plante ne soient changésPhosphorus (P) is essential for potatoes, the main crop in the Canadian eastern provinces. The depletion of phosphate reserves and the risk of loss of this element in watercourses are major constraints for food security and for environment. The objective of this study is to optimize the rate and type of phosphate fertilizer in order to minimize the risk of P accumulation in the soil, and to substitute synthetic fertilizers with recycled ones. A total of 141 soil samples representative of Prince Edward Island (PEI) soils were first analyzed. It have been shown that soil acidity greatly influenced P soil saturation percentage. Thus, critical thresholds in terms of P saturation index, (P/Al)M3, were 19% for very acid soils (pHwater 5.5), above which P fertilization should be limited to the crop’s requirement. Six environmental risk classes were identified and their spatial distribution showed that the moderate risk class was predominant in PEI. We then developed an agro-environmental model of P for potato based on 42 fertilization trials conducted in the Maritime provinces (PEI, New Brunswick (NB) and Nova Scotia (NS)). This model, based on the (P/Al)M3 index, was composed of seven fertility and environmental risk classes: (0-2.5%), (2.5%-5%), (5%-10%), (10%-14%), (14%-16%), (16%-23%) and (P/Al)M3>23% corresponding, respectively, to the optimal P rates of 105, 81, 70 kg P ha-1 for the first three classes, and to a P rate of 21 kg ha-1 for classes with (P/Al)M3 greater than 10%. Finally, to evaluate the effectiveness of a recycled P fertilizer (Crystal Green®), we conducted 8 fertilization trials in Quebec and in the Maritime provinces. It was concluded that P fertilization with Crystal Green® could substitute triple superphosphate (TSP) up to 75% without noticing any significant decrease in potato yield levels, P uptake, and P status in the soil and in the plant

Leveraging BERT Language Models for Multi-Lingual ESG Issue Identification

Environmental, Social, and Governance (ESG) has been used as a metric to measure the negative impacts and enhance positive outcomes of companies in areas such as the environment, society, and governance. Recently, investors have increasingly recognized the significance of ESG criteria in their investment choices, leading businesses to integrate ESG principles into their operations and strategies. The Multi-Lingual ESG Issue Identification (ML-ESG) shared task encompasses the classification of news documents into 35 distinct ESG issue labels. In this study, we explored multiple strategies harnessing BERT language models to achieve accurate classification of news documents across these labels. Our analysis revealed that the RoBERTa classifier emerged as one of the most successful approaches, securing the second-place position for the English test dataset, and sharing the fifth-place position for the French test dataset. Furthermore, our SVM-based binary model tailored for the Chinese language exhibited exceptional performance, earning the second-place rank on the test dataset

Efficiency of marker-assisted selection in detection of ascochyta blight resistance in Tunisian chickpea breeding lines

Ascochyta blight (AB) resistance reactions were studied in 23 chickpea cultivars, mainly advanced lines and Tunisian varieties from the Tunisian chickpea breeding program, growing both at two locations and under controlled conditions. Two co-dominant markers both associated with AB resistance were also used in this study; the CaETR marker tightly linked to QTLAR1 in combination with the SCAR SCY17590 marker linked to QTLAR2 to explore their usefulness in discriminating between resistant and susceptible chickpea genotypes. These two markers contribute efficiently in the selection of new chickpea varieties with better combinations of alleles to ensure durable resistance to AB. The advanced line V10 presenting the resistance allele for CaETR, but being still heterozygous for the SCAR17590 was characterized as resistant to moderately resistant in field studies and under controlled conditions. This line could be very useful for developing a new variety that is fixed for both resistance alleles and expresses good levels of resistance to AB in different chickpea cropping environments. These markers are very useful in assisting chickpea breeding programs, especially thanks to their robustness, their co-dominance and their utility across different genetic backgrounds

Antibody-mediated disruption of the interaction between PCSK9 and the low-density lipoprotein receptor

PCSK9 (proprotein convertase subtilisin/kexin type 9) promotes degradation of the LDLR [LDL (low-density lipoprotein) receptor] through an as-yet-undefined mechanism, leading to a reduction in cellular LDLc (LDL-cholesterol) and a concomitant increase in serum LDLc. Central to the function of PCSK9 is a direct protein–protein interaction formed with the LDLR. In the present study, we investigated a strategy to modulate LDL uptake by blocking this interaction using specific antibodies directed against PCSK9. Studies using surface plasmon resonance demonstrated that direct binding of PCSK9 to the LDLR could be abolished with three different anti-PCSK9 antibodies. Two of these antibodies were raised against peptide epitopes in a region of the catalytic domain of PCSK9 that is involved in the interaction with the LDLR. Such antibodies restored LDL uptake in HepG2 cells treated with exogenous PCSK9 and in HepG2 cells engineered to overexpress recombinant PCSK9. This latter observation indicates that antibodies blocking the PCSK9–LDLR interaction can inhibit the action of PCSK9 produced endogenously in a cell-based system. These antibodies also disrupted the higher-affinity interaction between the natural gain-of-function mutant of PCSK9, D374Y, and the LDLR in both the cell-free and cell-based assays. These data indicate that antibodies targeting PCSK9 can reverse the PCSK9-mediated modulation of cell-surface LDLRs

Prion protein interacts with bace1 and differentially regulates its activity towards wild type and swedish mutant amyloid precursor protein

In Alzheimer disease amyloid-β (Aβ) peptides derived from the amyloid precursor protein (APP) accumulate in the brain. Cleavage of APP by the β-secretase BACE1 is the rate-limiting step in the production of Aβ. We have reported previously that the cellular prion protein (PrP(C)) inhibited the action of BACE1 toward human wild type APP (APP(WT)) in cellular models and that the levels of endogenous murine Aβ were significantly increased in PrP(C)-null mouse brain. Here we investigated the molecular and cellular mechanisms underlying this observation. PrP(C) interacted directly with the prodomain of the immature Golgi-localized form of BACE1. This interaction decreased BACE1 at the cell surface and in endosomes where it preferentially cleaves APP(WT) but increased it in the Golgi where it preferentially cleaves APP with the Swedish mutation (APP(Swe)). In transgenic mice expressing human APP with the Swedish and Indiana familial mutations (APP(Swe,Ind)), PrP(C) deletion had no influence on APP proteolytic processing, Aβ plaque deposition, or levels of soluble Aβ or Aβ oligomers. In cells, although PrP(C) inhibited the action of BACE1 on APP(WT), it did not inhibit BACE1 activity toward APP(Swe). The differential subcellular location of the BACE1 cleavage of APP(Swe) relative to APP(WT) provides an explanation for the failure of PrP(C) deletion to affect Aβ accumulation in APP(Swe,Ind) mice. Thus, although PrP(C) exerts no control on cleavage of APP(Swe) by BACE1, it has a profound influence on the cleavage of APP(WT), suggesting that PrP(C) may be a key protective player against sporadic Alzheimer disease

Chloroquine is a potent inhibitor of SARS coronavirus infection and spread

BACKGROUND: Severe acute respiratory syndrome (SARS) is caused by a newly discovered coronavirus (SARS-CoV). No effective prophylactic or post-exposure therapy is currently available. RESULTS: We report, however, that chloroquine has strong antiviral effects on SARS-CoV infection of primate cells. These inhibitory effects are observed when the cells are treated with the drug either before or after exposure to the virus, suggesting both prophylactic and therapeutic advantage. In addition to the well-known functions of chloroquine such as elevations of endosomal pH, the drug appears to interfere with terminal glycosylation of the cellular receptor, angiotensin-converting enzyme 2. This may negatively influence the virus-receptor binding and abrogate the infection, with further ramifications by the elevation of vesicular pH, resulting in the inhibition of infection and spread of SARS CoV at clinically admissible concentrations. CONCLUSION: Chloroquine is effective in preventing the spread of SARS CoV in cell culture. Favorable inhibition of virus spread was observed when the cells were either treated with chloroquine prior to or after SARS CoV infection. In addition, the indirect immunofluorescence assay described herein represents a simple and rapid method for screening SARS-CoV antiviral compounds

Calmodulin interacts with angiotensin-converting enzyme-2 (ACE2) and inhibits shedding of its ectodomain

AbstractAngiotensin-converting enzyme-2 (ACE2) is a regulatory protein of the renin–angiotensin system (RAS) and a receptor for the causative agent of severe-acute respiratory syndrome (SARS), the SARS-coronavirus. We have previously shown that ACE2 can be shed from the cell surface in response to phorbol esters by a process involving TNF-α converting enzyme (TACE; ADAM17). In this study, we demonstrate that inhibitors of calmodulin also stimulate shedding of the ACE2 ectodomain, a process at least partially mediated by a metalloproteinase. We also show that calmodulin associates with ACE2 and that this interaction is decreased by calmodulin inhibitors

Hysteretic Behavior of Proprotein Convertase 1/3 (PC1/3)

The proprotein convertases (PCs) are calcium-dependent proteases responsible for processing precursor proteins into their active forms in eukariotes. The PC1/3 is a pivotal enzyme of this family that participates in the proteolytic maturation of prohormones and neuropeptides inside the regulated secretory pathway. In this paper we demonstrate that mouse proprotein convertase 1/3 (mPC1/3) has a lag phase of activation by substrates that can be interpreted as a hysteretic behavior of the enzyme for their hydrolysis. This is an unprecedented observation in peptidases, but is frequent in regulatory enzymes with physiological relevance. The lag phase of mPC1/3 is dependent on substrate, calcium concentration and pH. This hysteretic behavior may have implications in the physiological processes in which PC1/3 participates and could be considered an additional control step in the peptide hormone maturation processes as for instance in the transformation of proinsulin to insulin