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Zooming in on methylation of homogalacturonan pectins: How degree and pattern dictate physicochemical properties, bioactivities, and potential applications
No full textInternational audienceHomogalacturonan (HG)-type pectin, as the most abundant and widely used pectin, possesses excellent pro cessing properties and health-promoting effects. The degree and pattern of methylation are key structural features of HG-type pectin that influence its functionalities. However, the relationship between these chemicalstructures and their functional properties has not been fully explored. Therefore, this paper reviews the methylation and demethylation strategies for regulating the degree of methylation (DM) and degree of blockiness (DB) of HG-type pectin, as well as the effects of DM and DB on its physicochemical properties, bioactivities, andpotential applications. DM and DB directly influence the molecular conformation, charge distribution, amphiphilic balance, and gelation behavior of pectin by regulating the number and distribution pattern of carboxyl and methyl ester groups along the HG chain. This further governs its interaction intensity and patterns with substances/cells, leading to differentiated efficacy or functional optimization. This work will promote the targeted design and utilization of HG-type pectin based on DM and DB, as well as research on its structure-function relationship
From shape to source: sedimentary charcoal morphology as a proxy for tropical burned biomass composition
No full textInternational audienceSedimentary charcoal elongation is increasingly being used in paleoecology to distinguish herbaceous from woody fuel in past fires. However, the relationship between charcoal morphotypes and plant types has never been formally tested in tropical environments, despite its potential to improve understanding of fire regimes and deforestation, and to analyze long-term ecosystem resilience. Separation between herbaceous and woody charcoal commonly relies on a fixed elongation threshold, but this arbitrary division overlooks the morphological continuum of charcoal and may bias interpretations. To address this, we developed a Bayesian model to classify charcoal fragments into herbaceous and woody subpopulations based on their elongation distributions. We applied it to 19 sediment charcoal records spanning the last 30 years across a broad geographic and vegetation gradient in West and Central Africa. Compared with contemporary vegetation cover derived from remote sensing, the estimated proportion of woody charcoal was significantly positively correlated with tree cover, validating our approach and confirming charcoal elongation as a reliable proxy for past fire-related biomass sources. Finally, we applied the model to a paleosequence from Lake Sélé (Benin) to reconstruct temporal changes in biomass and compared results with fossil pollen data, further assessing the proxy relevance for reconstructing past fire regimes and advancing tropical paleoecology
Kinetics of Lactic Acid, Acetic Acid and Ethanol Production During Submerged Cultivation of a Forest Litter-Based Biofertilizer
No full textInternational audienceFermented forest litter (FFL) is a biofertilizer obtained by anaerobic fermentation of forest litter combined with agricultural by-products. Its production involves an initial one-month solid-state fermentation of oak litter mixed with whey, molasses and wheat bran, followed by a one-week submerged fermentation-called the "activation" phase-during which the solid FFL is fermented with sugarcane molasses diluted in water. This study aimed to evaluate the effects storage duration (6, 18 and 30 months), and temperature (ambient and 29 • C) on the activation phase. For this purpose, pH, sugar consumption and metabolite production dynamics were monitored. Under all experimental conditions, the pH dropped to values close to 3.5, sucrose was rapidly hydrolyzed, and glucose was preferentially consumed over fructose. Fructose was metabolized only after glucose was depleted, suggesting the involvement of fructophilic microorganisms. The time-course evolution of lactic acid (LA) concentration was adequately fitted by the Gompertz model (R 2 > 0.970). The highest LA max concentration (6.30 g/L) and production rate (2.16 g/L•d) were obtained with FFL stored for 6 months. Acetic acid (AA) and ethanol were also detected reaching maxima values of 1.19 g/L and 0.96 g/L, respectively. Their profiles varied depending on the experimental conditions. Notably, the AA/LA ratio increased with the age of the FFL. Overall, sugar consumption and metabolite production were significantly slower at ambient temperature, than at 29 • C. These results contribute to a better understanding of the metabolic dynamics during FFL activation and highlight key parameters that should be considered to optimize future biofertilizer production processes
Classe flexible et formation initiale en master FLE :Effets sur les pratiques professionnelles et représentations des futurs enseignants
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Machine Learning for the Prediction of Size and Encapsulation Efficiency of mRNA-Loaded Lipid Nanoparticles Following a Postencapsulation Approach
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Growth and phosphorus uptake of micropropagated southern highbush blueberry plants inoculated with ericoid endophytic and mycorrhizal fungi in varied growth substrates
No full textInternational audiencePhosphorus (P) acquisition and use by southern highbush blueberry Vaccinium corymbosum L. plants is critical during early stages of development and impair root development, especially for growth substrates with poor nutrient contents. However, inoculation of blueberry plants with ericoid mycorrhizal fungi (ErMF) or dark septate endophytes (DSE) can improve P during the plants acclimation stages and reduce plant mortality, especially in dry northern Mediterranean climate conditions. Herein, we grew southern highbush blueberry micro-cuttings in conditions without inoculation (control) or in inoculated with four strains: two Ericoid mycorrhizal sp. (D01), and (C01), E. endophyte (C31), and Phialocephala fortinii Wang & Wilcox in sandy (S), fresh field (FF), and FF+S soil mix substrates for 10 months before harvest. At harvest, root colonization levels, plant height, leaf area, the fresh matter of roots and shoots, root-to-shoot ratio, P content, and P utilization efficiency (PUE) were measured. We found that the root colonization levels were inhibited in the S for the different inoculated F treatments, owing to the elevated carbonate and salt concentrations present. The average P uptake responses from the different F inoculated strains were 52.2 %, 29.6 %, and 22.4 % in the S, FF, and FF+S substrates. Inoculation of blueberry plants with C31 strain exhibited the highest (59.1 %) P uptake average response, inoculation with P. fortinii strain showed the lowest (15.8 %) response. The root growth responses were inhibited in the FF+S (-0.2 %), increased in the S (8.4 %), and FF (6.2 %) substrates. Our findings therefore describe responses under controlled nursery conditions with single-strain inoculation and three substrate types. Because blueberry roots in the field are commonly co-colonized by multiple ericoid and endophytic fungi, interactions among partners may amplify or dampen the effects observed here; future work should test coinoculation consortia and validate performance under field conditions.</div
Autonomic cardiac regulation to slow-paced respiration in seated and supine positions
No full textInternational audiencePurpose: Respiratory modulation and positional control are the main two regulators of cardiac autonomic activity. Although both slow-paced breathing and supine position promote parasympathetic regulation, their interaction remains poorly documented. Here, the objective of this work is to study the interaction between these two autonomic controls. Methods: Twenty healthy volunteers (12 males, 8 females), age of 25.9 ± 3.9 years were included in this study. They were randomly subjected to 6 different slow and controlled breathing at 4.5, 5, 5.5, 6, 6.5, and 7 min/cycles for 3 min in supine or seated position after a 3 min baseline recording in spontaneous breathing. ECG was continuously monitored and RR intervals (RRI), total power (Ptot), the standard deviation of normal R-R intervals (SDNN), high frequency power (HF), the root mean square of successive R-R interval differences (RMSSD), and low frequency power (LF) were calculated to study autonomic regulation. Results: We observed (1) a similar increase in parasympathetic (RMSSD and LF) and overall autonomic (RRI, Ptot, and SDNN) activities in slow-paced breathing conditions, whatever the respiratory rate in comparison with control spontaneous breathing; (2) these autonomic parameters increased in sitting position, but in parasympathetic (RMSSD and LF) and overall autonomic (Ptot, and SDNN) activities interacted with respiratory control and were higher in seated slow-paced breathing. Conclusion: These results showed that (1) whatever the slow-paced breathing frequency, slow breathing favours parasympathetic control and slow heart rhythm; and (2) seated position favors autonomic cardiovascular interaction between respiratory modulation and positional control
Decoding Tocopherol-Polyphenol interactions in oil-in-water emulsions through combined WIM-CAT and CV assays
No full textSource Agritrop Cirad (https://agritrop.cirad.fr/616786/) * Autres projets (id;sigle;titre): 101158035;PassIon;(EU) High Performance and Large-Scale Electrodes for Selective Ion Recovery//International audienceThe antioxidant interactions of α- and γ-tocopherol with curcumin and quercetin were assessed in an oil-in-water emulsion using the WIM-CAT assay, a method integrating Weibull interaction modeling with the conjugated autoxidizable triene technique. Synergistic effects were strongest for γ-tocopherol with curcumin and for α-tocopherol with quercetin, particularly at low tocopherol concentrations (0.2 μM in emulsion, 380 ppm in oil) and high molar ratios (3:1). Increasing tocopherol concentration to 0.6 μM in emulsion (1140 ppm in oil) reduced synergy, likely reflecting pro-oxidant activity. The presence of ferrous ions accelerated oxidation but did not influence synergistic interactions, while acidic conditions reduced tocopherol pro-oxidation and modified the effects of curcumin and quercetin. Weibull modeling revealed isoform-dependent differences during the propagation phase of oxidation. Cyclic voltammetry further suggested that the synergy of α-tocopherol may involve antioxidant regeneration mechanisms, whereas γ-tocopherol appears to act through alternative redox processes. Together, kinetic and electrochemical analyses provide complementary insights into the conditions governing antioxidant interactions
Conservacionismo, protesta ambiental y emergencia del ecologismo político en España, del Franquismo a la Democracia (Galicia, Aragón y Andalucía)
No full textInternational audienceThe aim of this article is to provide an approach to the history of environmentalism and to bring new perspectives to the study of Francoism and the Spanish transition by analyzing environmental conflicts on a regional scale. In response to the industrial, energy and urban planning policies of the regime, the main environmental conflicts of the period between 1960 and 1986 have proved to be a perfect historical laboratory for understanding in all their complexity the profound social and political transformations of the period. The methodology employed consists of consulting municipal, regional and national archives, press analyses and subsequently comparing our case studies (Galicia, Aragon and Andalusia). Through in-depth case studies of Aragon, Galicia and Andalusia, we observe the path from popular protest against environmental injustice to the subsequent formalization of an environmentalist political ideology in the 1980s. The article aims to highlight the links between popular environmentalism, social memory and processes of politicisation of the territory during the late Franco era and the TransitionEl objetivo de este artículo es dar un enfoque a la historia del ecologismo y aportar nuevas perspectivas al estudio del franquismo y la transición española, analizando los conflictos ambientales a escala regional. En respuesta a las políticas industriales, energéticas y urbanísticas del régimen, los principales conflictos ambientales del periodo compren-dido entre 1960 y 1986 se han revelado como un laboratorio histórico ideal para comprender en toda su complejidad las profundas transformaciones sociales y políticas del periodo. La metodología empleada consiste en la consulta de archivosmunicipales, regionales y nacionales, análisis de prensa y una posterior comparación en nuestros casos de estudio (Galicia, Aragón y Andalucía). A través de los estudios en profundidad de estos casos de Aragón, Galicia y Andalucía, analizamos el camino desde la protesta popular contra la injusticia ambiental hasta la posterior formalización de una ideología política ecologista en los años ochenta. El artículo pretende poner de relieve los vínculos entre ecologismo popular, memoria social y procesos de politización del territorio durante el tardofranquismo y la Transición