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Disease severity in coinfected hosts: the importance of infection order.
No full textInternational audienceWhen hosts are simultaneously infected by different pathogens, the severity of the disease might be altered compared to hosts harboring single infections. The reasons underlying these changes in parasite virulence are manifold. Here, we investigated the importance of order and timing of infection. We used a model of rodent coinfection between two parasites that do not compete for common resources, an intestinal nematode ( Heligmosomoides polygyrus, Hp) and an apicomplexan protozoan ( Plasmodium yoelii, Py). During single infections, Hp induced only mild disease symptoms. Plasmodium produced a substantial reduction in the number of red blood cells but all mice recovered from the infection. A different picture emerged in coinfected hosts. Hp maintained a profile of mostly asymptomatic infection when infecting hosts that had been previously infected with Py. On the contrary, Py incurred substantially higher costs in hosts that had been previously infected with Hp. We then investigated the possible reasons underlying the increase of Py virulence in hosts that had been previously infected with Hp. We found that coinfected hosts were less able to control Py multiplication and to recover from infection-induced anemia. Coinfected hosts had similar levels of erythropoietin and similar renewal of lost red blood cells compared to single Py infected hosts, resulting in decreased tolerance to Py infection. Experimental administration of erythropoietin in coinfected (Hp infecting first) hosts, partially decreased the severity of disease symptoms and improved tolerance. The detoxification of free heme released during the lysis of red blood cells, and the expression of Th1 and anti-inflammatory cytokine genes were also similar between coinfected and single infected hosts. However, coinfected mice had higher proportions of regulatory T cells expressing the CTLA-4 immune checkpoint, suggesting an enhanced immunosuppressive activity of Tregs. Py infection also induced the exhaustion of CD8 + T cells, as coinfected mice had higher proportions of both PD-1 + and LAG-3 + CD8 + T cells, and an increase in the CD4 + /CD8 + ratio. Overall, these results stress the importance of the order of infection as a major determinant of malaria severity in hosts harboring a gastrointestinal nematode infection. We discuss the possible epidemiological and evolutionary consequences of these results
Impact of emerging packaging regulations on international trade and product safety with emphasis on plastic reuse and recycling in Europe and North America
No full textInternational audienceThe evolving global landscape of packaging regulations, driven by heightened public concern over single-use packaging and plastic waste, signals a significant shift toward circular economy principles. These regulatory changes, including the United Nations Environmental Programme's endorsement of a legally binding international agreement on plastic waste management, are expected to have far-reaching impacts on product safety, packaging design, and global trade. The newly adopted and emerging policies prioritize waste reduction, reuse, recycling, and the integration of recycled materials. However, the rapid introduction of environmentally driven packaging regulations-especially those targeting sensitive sectors like food and cosmetics-presents potential risks for product/packaging safety and food waste, alongside challenges for trade harmonization across regions with divergent regulatory goals. This forum article reviews key regulatory frameworks from Asia, Europe, and the Americas, detailing material bans, reuse and refill targets, recycling mandates, and extended producer responsibility initiatives. It examines the potential impact of these regulations on global trade dynamics and their implications for universally accepted safety standards. Despite the well-meaning intent behind these laws, gaps in understanding the protective role of packaging and its broader environmental impact may lead to misconceptions in developing sustainable product-packaging systems. Current policies primarily target waste reduction, but an integrated approach is needed - one that considers how packaging extends food shelf life, lowers resource use, and reduces greenhouse gas emissions. Consumer education and transparent communication from regulators and industry will guide informed, sustainable choices, ultimately supporting a more transparent shift toward a circular economy
Quelles réponses comportementales de la part des consommateurs vis-à-vis des marques faisant l’objet de scandales ?
No full textInternational audienceUne étude de cas, prenant la forme d’une analyse documentaire, a été réalisée afin de comprendre de caractériser et de classifier les réponses comportementales des consommateurs d’une marque ayant fait l’objet d’un scandale, et ce en fonction du niveau de haine ressentie. Douze entreprises, issues de domaines d’activités stratégiques différents, ayant dû récemment faire face à une crise majeure ont été étudiées pour mettre en exergue et expliquer les réactions comportementales des consommateurs. Une grille de lecture proposant d’établir des liens entre les comportements des entreprises, les réactions des consommateurs et les réponses des entreprises a été établie. Nos résultats confirment la littérature sur les comportements des entreprises (Makarem et Jae, 2016) et les liens entre haine et résistance (Buffaz, Perraud, Rodriguez, 2024) et permettent de recommander aux marques une réponse appropriée et spécifique à chaque réaction des consommateurs en fonction du type de scandale identifié
Study of the compressive behaviour of natural cork under exposure to water and ethanol vapours during ageing
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La double matérialité : un objet-frontière pour une meilleure intégration des parties prenantes dans la RSE ?
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Reducing greenhouse gas emissions from soils by reducing N2O to N2
No full textThis issue follows on from the Carrefour de l'innovation agronomique, forum dedicated to reducing the carbon footprint of agricultural and agri-food activities, which took place on September 19, 2024: - analyzing the trajectory of carbon footprint reduction in various activities related to agriculture and food (crops, livestock, agricultural inputs, food production) based on certain innovations- how stakeholders in agriculture and agri-food are committed to innovation aimed at carbon neutrality.International audienceThe mitigation of greenhouse gas (GHG) emissions, particularly nitrous oxide (N2O) from agricultural soils, is crucial given the unprecedented atmospheric concentrations of GHGs such as carbon dioxide (CO2), methane (CH4), and N2O, which have continued to rise rapidly since industrialization. Agricultural soils represent a major source of N2O, a potent greenhouse gas with significant global warming potential. We explore the evolution and application over time of biotechnical strategies aimed at mitigating N2O emissions in soils. Here, we present two key mitigation approaches: (1) climatic liming which involves liming addition to attain a soil pH of 6.8, and (2) the inoculation of legumes with rhizobial strains harbouring nosZ genes, known to encode for N2O reductase. These approaches are based on prior research conducted to demonstrate their respective efficacy in stimulating N2O conversion to N2 in soil. Additionally, our findings from climatic liming point towards its potential to mitigate soil CO2 emissions although further research is required to understand the underlying mechanisms, environmental determinants, and broader applicability of this approach
Space–time multimode helical light bullets in ring-core fibers
No full textInternational audienceThis article demonstrates that ring-core fibers support the propagation of light bullets, i.e., space-time multimode solitons, regardless of the group velocity dispersion regime. These space-time wavepackets rigidly rotate in both space and time during propagation due to the dynamic equilibrium between space-and time-group velocity dispersion and the Kerr effect. The presented analytical solutions can propagate over hundreds of nonlinear lengths without significant space-time distortion, despite suffering from modulational instabilities. Finally, it is numerically shown that helical solitons, which are solutions of the scalar two-dimensional nonlinear Schrödinger equation, remain robust even when higher-order effects are taken into account. In particular, simulations reveal that spin-orbit coupling does not alte
Critical habitat thresholds for effective pollinator conservation in agricultural landscapes
No full textInternational audienceBiodiversity in human-dominated landscapes is declining, but evidence-based conservation targets to guide international policies for such landscapes are lacking. We present a framework for informing habitat conservation policies based on the enhancement of habitat quantity and quality and define thresholds of habitat quantity at which it becomes effective to also prioritize habitat quality. We applied this framework to insect pollinators, an important part of agroecosystem biodiversity, by synthesizing 59 studies from 19 countries. Given low habitat quality, hoverflies had the lowest threshold at 6% semi-natural habitat cover, followed by solitary bees (16%), bumble bees (18%), and butterflies (37%). These figures represent minimum habitat thresholds in agricultural landscapes, but when habitat quantity is restricted, marked increases in quality are required to reach similar outcomes
