26 research outputs found

    A clash on the Toll pathway: competitive action between pesticides and zymosan A on components of innate immunity in Apis mellifera

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    BackgroundThe immune system of honeybees includes multiple pathways that may be affected by pesticide exposure decreasing the immune competencies of bees and increasing their susceptibility to diseases like the fungal Nosema spp. infection, which is detected in collapsed colonies.MethodsTo better understand the effect of the co-presence of multiple pesticides that interact with bees like imidacloprid and amitraz, we evaluated the expression of immune-related genes in honeybee hemocytes.ResultsImidacloprid, amitraz, and the immune activator, zymosan A, mainly affect the gene expression in the Toll pathway.DiscussionImidacloprid, amitraz, and zymosan A have a synergistic or an antagonistic relationship on gene expression depending on the level of immune signaling. The presence of multiple risk factors like pesticides and pathogens requires the assessment of their complex interaction, which has differential effects on the innate immunity of honeybees as seen in this study

    Biofuel production using thermochemical conversion of heavy metal-contaminated biomass (HMCB) harvested from phytoextraction process

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    Over the past few decades, bioenergy production from heavy metal-contaminated biomasses (HMCBs) has been drawing increasing attention from scientists in diverse disciplines and countries owing to their potential roles in addressing both energy crisis and environmental challenges. In this review, bioenergy recovery from HMCBs, i.e. contaminated plants and energy crops, using thermochemical processes (pyrolysis, gasification, combustion, and liquefaction) has been scrutinized. Furthermore, the necessity of the implementation of practical strategies towards sustainable phytoextraction and metal-free biofuels production has been critically discussed. To meet this aim, the paper firstly delivers the fundamental concepts regarding the remediation of the brownfields using phytoremediation approach, and then, reviews recent literature on sustainable phytoextraction of heavy metals from polluted soils. Thereafter, to find out the possibility of the cost-efficient production of metal-free biofuels from HMCBs using thermochemical methods, the impacts of various influential factors, such as the type of feedstock and metals contents, the reactor type and operating conditions, and the role of probable pre-/post-treatment on the fate of heavy metals and the quality of products, have also been discussed. Finally, based on relevant empirical results and techno-economic assessment (TEA) studies, the present paper sheds light on pyrolysis as the most promising thermochemical technique for large-scale electricity and heat recovery from HMCBs

    Analyse de la mobilité des macrophages pour le développement d'un biocapteur atmosphérique

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    Not availableL'action des polluants atmosphériques sur la mobilité et la physiologie des macrophages alvéolaires est mal connue pour les expositions à court terme. Un bioessai basé sur la reconnaissance d'images est utilisé pour mesurer la variation de VAS (vitesse d'accroissement de surface) des cellules en déplacement. Le fMLP (formyl Méthionine Leucine Phénylalanine) a été retenu comme activateur de la mobilité cellulaire, ce dernier donnant une relation dose-réponse et un déplacement significatif sur la durée d'analyse. La VAS de macrophages activés (100 [mu]l de fMLP à 10[puissance -5] M) après exposition à 0,5 ppm d'ozonze (O[exposant]3) pendant 10 minutes a diminué la VAS d'un facteur 4 par rapport à la série témoin. Ces résultats ont permis de réaliser un biocapteur atmosphérique fonctionnant en continu. L'ozone affecte la VAS des macrophages. Cette altération peut être modélisée par une relation polynomiale. En ce qui concerne le monoxyde d'azote (NO), des concentrations comprises entre 157 ppb et 1125 ppb ont altéré la VAS de façon significative. Un mélange composé d'O3 et de Nox a provoqué une diminution de VAS d'environ 70%. Le prototype permet donc de mettre en évidence les pollutions liées au NO et à O3 dans les limites des normes européennes. Après avoir vérifié l'influence de O3 sur la VAS , les répercussions physiologiques de ce polluant ont été abordées dans les conditions du bioessai. La concentration de 0,5 ppm est cytotoxique avec un TL50 atteinte pour 28 mn d'exposition. De plus, cette agression modifie la concentration de calcium intercellulaire traduisant l'activation du métabolisme cellulaire. Celle-ci peut être corrélée à la libération de molécules de défenses (H2O2 et NO). L'exposition de macrophages à 0,5 ppm d'ozone conduit donc à une perte de mobilité et à l'activation des systèmes de protection de la cellul

    Comparison of two bacterial DNA extraction methods from non-polluted and polluted soils

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    Composition of root exudates of Miscanthus × Giganteus Greef et Deu

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    Rate of root exudation and identification of selected compounds in root exudates of Miscanthus × Giganteus in the autumnal period of growth was performed. Total organic carbon of root exudates was formed from 7.8 % by carbohydrates and from 1.5 % by proteins. Aspartic acid, arginine, alanine and glutamic acid were exuded with the highest rate of all amino acids. This work brings new basic know­led­ge which can be used for phytoremediations
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