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The potential of the FSP1cre-Pparb/d−/− Mouse model for studying juvenile NAFLD
No full textNon-alcoholic fatty liver disease (NAFLD) can progress from steatosis to non-alcoholicsteatohepatitis (NASH) characterized by liver inflammation, possibly leading to cirrhosis andhepatocellular carcinoma (HCC). Mice with impaired macrophage activation, when fed a high-fatdiet, develop severe NASH. Evidence is mounting that Kupffer cells are implicated. However, it isunknown whether the resident CD68+or bone marrow-derived CD11b+Kupffer cells are involved.Characterization of the FSP1cre-Pparb/d−/−mouse liver revealed that FSP1 is expressed in CD11b+Kupffer cells. Although these cells only constitute a minute fraction of the liver cell population,Pparb/ddeletion in these cells led to remarkable hepatic phenotypic changes. We report that a higher lipidcontent was present in postnatal day 2 (P2) FSP1cre-Pparb/d−/−livers, which diminished after weaning.Quantification of total lipids and triglycerides revealed that P2 and week 4 of age FSP1cre-Pparb/d−/−livers have higher levels of both. qPCR analysis also showed upregulation of genes involved in fattyacidβ-oxidation, and fatty acid and triglyceride synthesis pathways. This result is further supportedby western blot analysis of proteins in these pathways. Hence, we propose that FSP1cre-Pparb/d−/−mice, which accumulate lipids in their liver in early life, may represent a useful animal model tostudy juvenile NAFLD
Les productions animales dans la bioéconomie
No full textBioeconomy is defined as the set of activities related to the production of bioresources and their utilization and processing to meet human food requirements and contribute to society’s needs of energy and materials, while preserving natural resources and ecosystem services. In this paper, we describe and quantify the different flows of bioresources related to animal breeding. At the national level, animal farming systems are the main users of bioresources (113 Mt) and agricultural land (55 %) for animal feeding. They largely contribute to the supply of human food, mainly proteins (60 %), lipids (40 %), minerals and vitamins. Through their utilisation of agricultural land and the production of organic manure, they contribute to the production of ecosystem services, such as biodiversity and soil fertility. The production of animal manure amounts to about 19.4 Mt organic matter corresponding to a potential methane production equivalent to 45 TWh primary energy, with only a minor part of it produced until now. Due to their importance, animal production systems are thus major factors for balancing or disrupting biogeochemical cycles, ecosystem services and biodiversity. Significant margins of progress exist to improve their contribution to meeting human needs, better close nutrient cycles, improve autonomy, and reduce inputs and losses to the environment. With this in mind, we discuss some challenges and opportunities for a better integration of animal production into a circular bioeconomy.La bioéconomie se définit comme l’ensemble des activités liées à la production, l’utilisation et la transformation de bioressources pour répondre de façon durable aux besoins alimentaires et à une partie des besoins en énergie et en matériaux de la société, tout en préservant les ressources naturelles et en garantissant la production de services environnementaux. Dans cet article nous décrivons et quantifions les différents flux de bioressources associés aux activités d’élevage. À l’échelle nationale, les systèmes d’élevage sont les principaux utilisateurs de bioressources (113 Mt) et de surfaces agricoles (55 %), pour l’alimentation des animaux. Ils contribuent largement aux apports alimentaires de l’Homme, principalement en protéines (60 %), lipides (40 %), minéraux et vitamines. Par leur utilisation des surfaces agricoles et la production d’effluents organiques ils contribuent également à la fourniture de services écosystémiques, comme la biodiversité et la fertilité des sols. Les effluents d’élevages représentent environ 19,4 Mt de matière organique correspondant à un potentiel de production de méthane équivalent à 45 TWh d’énergie primaire, très peu valorisé pour le moment. De par son importance, l’élevage constitue donc un facteur majeur d’équilibre ou de perturbation des cycles biogéochimiques, des services écosystémiques et de la biodiversité. Il existe des marges importantes de progrès pour accroître sa contribution à la couverture des besoins humains et mieux boucler les cycles de matières, en améliorant l’autonomie, en économisant des intrants et en diminuant les pertes vers l’environnement. Dans cette perspective, nous discutons les défis et les opportunités d’une meilleure intégration de l’élevage dans la bioéconomie circulaire
Human peripheral blood eosinophils express high level of the purinergic receptor p2x4
No full textExtracellular nucleotides are important mediators of cell activation and trigger multiple responses via membrane receptors known as purinergic receptors (P2). P2X receptors are ligand-gated ion channels, activated by extracellular ATP. P2X4 is one of the most sensitive purinergic receptors, that is typically expressed by neurons, microglia, and some epithelial and endothelial cells. P2X4 mediates neuropathic pain via brain-derived neurotrophic factor and is also involved in inflammation in response to high ATP release. It is therefore involved in multiple inflammatory pathologies as well as neurodegenerative diseases. We have produced monoclonal antibodies (mAb) directed against this important human P2X4 receptor. Focusing on two mAbs, we showed that they also recognize mouse and rat P2X4. We demonstrated that these mAbs can be used in flow cytometry, immunoprecipitation, and immunohistochemistry, but not in Western blot assays, indicating that they target conformational epitopes. We also characterized the expression of P2X4 receptor on mouse and human peripheral blood lymphocytes (PBL). We showed that P2X4 is expressed at the surface of several leukocyte cell types, with the highest expression level on eosinophils, making them potentially sensitive to adenosine triphosphate (ATP). P2X4 is expressed by leucocytes, in human and mouse, with a significant gender difference, males having higher surface expression levels than females. Our findings reveal that PBL express significant levels of P2X4 receptor, and suggest an important role of this receptor in leukocyte activation by ATP, particularly in P2X4(high) expressing eosinophils
Comparative genomics reveals ecological and evolutionary insights into sponge-associated Thaumarchaeota
No full textThaumarchaeota are frequently reported to associate with marine sponges (phylum Porifera); however, little is known about the features that distinguish them from their free-living thaumarchaeal counterparts. In this study, thaumarchaeal metagenome-assembled genomes (MAGs) were reconstructed from metagenomic data sets derived from the marine sponges Hexadella detritifera, Hexadella cf. detritifera, and Stylissa flabelliformis. Phylogenetic and taxonomic analyses revealed that the three thaumarchaeal MAGs represent two new species within the genus Nitrosopumilus and one novel genus, for which we propose the names "Candidatus (u)Nitrosopumilus hexadellus," "Candidatus (u)Nitrosopumilus detritiferus," and "Candidatus (u)Cenporiarchaeum stylissum" (the U superscript indicates that the taxon is uncultured). Comparison of these genomes to data from the Sponge Earth Microbiome Project revealed that "Ca. (u)Cenporiarchaeum stylissum" has been exclusively detected in sponges and can hence be classified as a specialist, while "Ca. (u)Nitrosopumilus detritiferus" and "Ca. (u)Nitrosopumilus hexadellus" are also detected outside the sponge holobiont and likely lead a generalist lifestyle. Comparison of the sponge-associated MAGs to genomes of free-living Thaumarchaeota revealed signatures that indicate functional features of a sponge-associated lifestyle, and these features were related to nutrient transport and metabolism, restriction-modification, defense mechanisms, and host interactions. Each species exhibited distinct functional traits, suggesting that they have reached different stages of evolutionary adaptation and/or occupy distinct ecological niches within their sponge hosts. Our study therefore offers new evolutionary and ecological insights into the symbiosis between sponges and their thaumarchaeal symbionts. IMPORTANCE Sponges represent ecologically important models to understand the evolution of symbiotic interactions of metazoans with microbial symbionts. Thaumarchaeota are commonly found in sponges, but their potential adaptations to a host-associated lifestyle are largely unknown. Here, we present three novel sponge-associated thaumarchaeal species and compare their genomic and predicted functional features with those of closely related free-living counterparts. We found different degrees of specialization of these thaumarchaeal species to the sponge environment that is reflected in their host distribution and their predicted molecular and metabolic properties. Our results indicate that Thaumarchaeota may have reached different stages of evolutionary adaptation in their symbiosis with sponges
Deposition of a cutin apoplastic barrier separating seed maternal and zygotic tissues
No full textBackground: In flowering plants, proper seed development is achieved through the constant interplay of fertilization products, embryo and endosperm, and maternal tissues. Communication between these compartments is supposed to be tightly regulated at their interfaces. Here, we characterize the deposition pattern of an apoplastic lipid barrier between the maternal inner integument and fertilization products in Arabidopsis thaliana seeds. Results: We demonstrate that an apoplastic lipid barrier is first deposited by the ovule inner integument and undergoes de novo cutin deposition following central cell fertilization and relief of the FERTILIZATION INDEPENDENT SEED Polycomb group repressive mechanism. In addition, we show that the WIP zinc-finger TRANSPARENT TESTA 1 and the MADS-Box TRANSPARENT TESTA 16 transcription factors act maternally to promote its deposition by regulating cuticle biosynthetic pathways. Finally, mutant analyses indicate that this apoplastic barrier allows correct embryo sliding along the seed coat. Conclusions: Our results revealed that the deposition of a cutin apoplastic barrier between seed maternal and zygotic tissues is part of the seed coat developmental program
Réponses postprandiales à l’ingestion de produits laitiers chez l’homme : effet du type de produit et de l’âge
No full textIntroduction et but de l’étude : De nombreuses études montrent que la consommation de produits laitiers (PL) est associée à des bénéfices pour la santé, mais ceux-ci peuvent différer en fonction du type de PL, notamment en raison de la fermentation. Cependant, associer la consommation de chaque PL avec des bénéfices santé spécifiques reste complexe en raison de la précision insuffisante de l'évaluation des profils de consommation par les relevés alimentaires. La métabolomique incluant des biomarqueurs de consommation de PL pourrait permettre une évaluation plus objective. Ces signatures sont aussi dépendantes des différences des réponses métaboliques, notamment au cours du vieillissement. Notre objectif est d’identifier les caractéristiques métaboliques postprandiales (PP) associées à la consommation de deux PL : lait (L) et lait fermenté avec les
bactéries du yaourt (Y) chez l’homme adulte et âgé.
Matériel et méthodes : Etude clinique randomisée, contrôlée et en cross-over sur des 28 hommes jeunes (14 J, 20-35 ans) et âgés (14 A, 65-80 ans) en bonne santé. Après 3 semaines d’exclusion de PL et de produits fermentés (PF), les sujets ont ingéré à jeun 600 mL de L ou de Y. Les niveaux de glucose, d’insuline, de triglycérides, de peptide insulinotrope dépendant du glucose (GIP), et Interleukine IL-6 ont été suivis durant les 6h après l’ingestion.
Résultats et Analyse statistique : L’augmentation des niveaux circulants de glucose a été plus importante 30 min après la consommation de L vs Y dans les 2 groupes d’âge (J : 6,0±0,2 vs 5,3±0,2, A : 5,9±0,2 vs 5,2±0,1 mmol/L, P<0,05), ce qui est confirmé par l’aire sous la courbe PP (AUC, J : -20±18 vs -67±12 P<0,05, A : 4±19 vs -20±17 P=0.06, mmol/L/min). L’insulinémie PP a également été plus importante après la consommation de L vs Y dans les 2 groupes (J : 204±30 vs 159±21, A : 147±17 vs 119±11 pmol/L à 30 min, P<0,05). Inversement, les taux circulants de GIP ont augmenté plus fortement 60 min après la consommation de Y vs L chez les J et les A (J : 347±33 vs 229±34, A : 406±50 vs 264±28 pg/ml, P<0,05). Concernant les effets liés à l’âge, la réponse
PP des niveaux de triglycérides a été plus importante chez les A vs J, indépendamment du produit consommé, et particulièrement 180 min après l’ingestion (AUC L : 72±11 vs 26±16, Y : 77±9 vs 40±15 mmol/L/min, P<0,05). Alors que nous n’avons pas observé de changement significatif chez les J, les niveaux d’IL-6 ont diminué chez les A 1h après la consommation de Y (-14% vs t0, P<0.05), avec une tendance similaire chez les J (-19% vs t0, p=0,12) après la consommation de L.
Conclusion : Ces résultats confirment que le changement de la matrice laitière suite à l’application de certains procédés (la fermentation) induit des différences de réponses métaboliques. Les réponses métaboliques peuvent être également influencées par l’âge des sujets. Les analyses métabolomiques en cours devraient permettre de préciser ces différences et d’identifier des biomarqueurs signant la consommation des différents PL.
Remerciements : Ce projet bénéfice d'un soutien financier de la part du CNIEL et Syndifrais
Two large reciprocal translocations characterized in the disease resistance-rich burmannica genetic group of Musa acuminata
No full textBackground and Aims Banana cultivars are derived from hybridizations involving Musa acuminata subspecies. The latter diverged following geographical isolation in distinct South-east Asian continental regions and islands. Observation of chromosome pairing irregularities in meiosis of hybrids between these subspecies suggested the presence of large chromosomal structural variations. The aim of this study was to characterize such rearrangements. Methods Marker (single nucleotide polymorphism) segregation in a self-progeny of the 'Calcutta 4' accession and mate-pair sequencing were used to search for chromosomal rearrangements in comparison with the M. acuminata ssp. malaccensis genome reference sequence. Signature segment junctions of the revealed chromosome structures were identified and searched in whole-genome sequencing data from 123 wild and cultivated Musa accessions. Key Results Two large reciprocal translocations were characterized in the seedy banana M. acuminata ssp. burmannicoides 'Calcutta 4' accession. One consisted of an exchange of a 240 kb distal region of chromosome 2 with a 7.2 Mb distal region of chromosome 8. The other involved an exchange of a 20.8 Mb distal region of chromosome 1 with a 11.6 Mb distal region of chromosome 9. Both translocations were found only in wild accessions belonging to the burmannicoides/burmannica/siamea subspecies. Only two of the 87 cultivars analysed displayed the 2/8 translocation, while none displayed the 1/9 translocation. Conclusion Two large reciprocal translocations were identified that probably originated in the burmannica genetic group. Accurate characterization of these translocations should enhance the use of this disease resistance-rich burmannica group in breeding programmes
Enhancing the antioxidant activity of technical lignins by combining solvent fractionation and ionic-liquid treatment
No full textA grass soda technical lignin (PB1000) underwent a process combining solvent fractionation and treatment with an ionic liquid (IL), and a comprehensive investigation of the structural modifications was performed by using high-performance size-exclusion chromatography, P-31 NMR spectroscopy, thioacidolysis, and GC-MS. Three fractions with distinct reactivity were recovered from successive ethyl acetate (EA), butanone, and methanol extractions. In parallel, a fraction deprived of EA extractives was obtained. The samples were treated with methyl imidazolium bromide ([HMIM]Br) by using either conventional heating or microwave irradiation. The treatment allowed us to solubilize 28 % of the EA-insoluble fraction and yielded additional free phenols in all the fractions, as a consequence of depolymerization and demethylation. The gain of the combined process in terms of antioxidant properties was demonstrated through 2,2-diphenyl-1-picrylhydrazyl (DPPH.) radical-scavenging tests. Integrating further IL safety-related data and environmental considerations, this study paves the way for the sustainable production of phenolic oligomers competing with commercial antioxidants
