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Marek’s Disease Virus Replication in Chicken Skin Reconstructed In Vitro: Evidence for Viral Particles in Corneocytes
No full textInternational audienceMarek’s disease (MD) is a lethal lymphoma of chickens, which is caused by MD virus (MDV), an alphaherpesvirus. MDV infects epithelial cells of the skin appendages, notably feather follicles, replicates in these cells and is shed into the environment exclusively from these tissues. Here, we tested whether chicken skin equivalents (SEs) can be used to model MDV infection. Primary chicken keratinocytes were seeded on a suspension of fibroblasts in collagen and induced to terminally differentiate at the air-liquid interface. A recombinant MDV expressing the Katushka fluorescent protein (MDV-KAT) was introduced into SEs by seeding of primary keratinocytes together with MDV-KAT-infected keratinocytes of the K8 cell line. KAT-mediated fluorescence increased during the culture of infected SEs, indicating virus infection and replication, while the expression of keratinocyte differentiation markers was not significantly altered by MDV infection. MDV did not spread to the dermal compartment of SEs, but localized to the upper layers of the epidermis. Viral particles were readily observed by electron microscopy in living keratinocytes and for the first time in cornified keratinocytes of the outermost layer of infected SEs, evidence for excretion of viral elements into environment. Finally, we demonstrated that two fluorescent vaccine strains of MDV, Rispens and herpesvirus of turkey, can infect and replicate in SEs. Taken together, this study establishes chicken SEs as an in vitro model for MDV infection
KMDSeeker : Un Nouvel Outil d’Aide à l’Annotation de Familles de Composés Chimiques
No full textInternational audienceL’annotation des signaux dans le cadre d’analyse d’empreintes métaboliques reste un défi majeur. Pour y répondre, nous avons développé KMDSeeker, un package R basé sur le Kendrick Mass Defect (KMD). Cette méthode de normalisation des masses permet d’aligner les composés partageant des motifs répétés en attribuant une masse entière à un groupe fonctionnel spécifique (ex. CH = 14,000 Da). Ainsi, des triglycérides aux chaînes de longueur variable présentent un même KMD, facilitant leur regroupement et l’annotation dans des mélanges complexes.Intégré à une application RShiny, KMDSeeker permet une annotation interactive et efficace des données issues de spectrométrie de masse. Après un peak-picking via Galaxy W4M, les tableaux clés (variableMetadata, sampleMetadata et dataMatrix) sont exploités pour visualiser les pics détectés et leur distribution selon le KMD.L’outil génère un KMD plot, affichant les valeurs de KMD en fonction de la masse nominale. L’utilisateur sélectionne un cluster (défini par CAMERA et XCMS) pour examiner les formules chimiques suggérées via EnviPat. Il peut ensuite valider ou non l’annotation et explorer les autres clusters partageant le même KMD, facilitant ainsi l’identification de motifs récurrents.Enfin, KMDSeeker permet d’intégrer et d’enrichir une base de données locale, mettant en évidence les standards et composés connus. Cela améliore la rapidité et la précision de l’annotation. Cet outil constitue ainsi une solution performante pour l’analyse et l’annotation semi-automatique, structurée et approfondie des familles de composés en spectrométrie de masse
Assessing the impacts of net-zero transport scenarios in France on biomass resources, hydrogen and electricity consumption
No full textInternational audienceThe transport sector in France accounts for 30 % of national emissions and will require significant decarbonization effort to achieve carbon neutrality in 2050. Various technological solutions, from electric vehicles to renewable fuel such as biofuels and e-fuels, as well as changes in demand are envisioned to reach this target. We build three technological foresight scenarios and two sufficiency variants, mainly based on different readings of the European regulations banning the sale of internal-combustion-engine vehicles and setting Sustainable Aviation Fuel incorporation rates. The transport, hydrogen and biomass sectors are modeled in system dynamics to assess the detail impacts of these scenarios on biomass resources and energy consumption. In all scenarios, the total electricity demand increases drastically, regardless of the technological choices made for the vehicle fleets, mainly due to the production of e-fuels for aviation. None of the technological scenarios studied suggest that biomass supply is unfeasible. However, in a scenario with low electrification, there is a potentially increased dependence on imports for waste oils and fats, and competing uses or tensions with other demand sectors may arise over some biomass for anaerobic digestion and lignocellulosic resources. To reduce these potential tensions and the demand for electricity, sufficiency measures seem necessary in addition to technological advancements
Du génoype au phénotype : approche métrique, génétique et physiologique de l'impact de l'Insulin-Like Growth Factor Type 1 (IGF-1) sur les variations de poids et de taille de 73 chiens
No full textL’espèce canine, avec plus de 400 races, présente une diversité morphologique unique au sein des mammifères, notamment en taille et en poids. Cette variabilité est en partie liée au gène IGF-1, facteur de croissance régulant développement, métabolisme et vieillissement, mais qui n’explique qu’environ 15 % des différences observées. Des travaux récents ont mis en évidence une variation génétique dans un ARN régulateur, IGF1-AS, modulant l’expression d’IGF-1. L’étude menée sur 74 chiens sains visait à confirmer les corrélations entre génotype, taux sanguin d’IGF-1 et phénotype. Les résultats ont validé une forte association entre poids, taille et IGF-1 plasmatique, avec une influence nette du génotype, particulièrement marquée pour les petits et grands formats, moins pour les gabarits moyens, suggérant le rôle d’autres gènes. Malgré des limites méthodologiques (effectif restreint, variabilité des mesures, erreurs analytiques), l’étude confirme l’importance d’IGF-1 dans la morphologie canine et éclaire l’impact de la sélection humaine. Les perspectives sont multiples : enrichir la base génétique canine, développer des tests prédictifs, intégrer le conseil génétique vétérinaire, mieux comprendre les liens entre IGF-1, longévité, cancers et maladies métaboliques, et, à terme, envisager de nouvelles thérapies ciblant cette voie biologique
Monitoring colostrum harvesting and distribution equipment cleanliness with adenosine triphosphate luminometry before and after recommendations to improve hygiene practices in French dairy farms
No full textInternational audienceThis observational study evaluated the effects of practical hygiene recommendations on cleanliness and bacterial contamination of equipment used to harvest and feed colostrum on 8 French dairy farms. The study was conducted in 2 phases: before (phase 1) and after (phase 2) the implementation of farm-specific recommendations. During each phase, equipment cleanliness (e.g., robot-compatible buckets, milking buckets, transfer buckets, bottles, nipples, nipple buckets, drenchers, and esophageal tube feeders [ET]) was assessed using ATP luminometry (through direct surface [ATP-S] and rinsing liquid [ATP-L] swabbing, expressed in relative light units [RLU]), visual scoring, and culture-based bacteriological analysis. Fresh colostrum samples were also collected and analyzed during each phase. A self-reported questionnaire administered during phase 1 identified critical control points for colostrum contamination, which informed the formulation of practical hygiene recommendations. Contamination thresholds were defined as ≥100,000 cfu/mL for total bacterial count (TBC) and ≥10,000 cfu/mL for total coliform count (TCC). Hygiene practices related to the operator, cow teats, and equipment varied considerably among farms, as did adherence to the recommended practices. Overall, lower RLU values were recorded on equipment surfaces during phase 2 compared with phase 1 (ATP-L: −1.51 log [±0.24], P < 0.001; ATP-S: −1.15 log [±0.24], P < 0.001). These reductions were associated with good operator hygiene practices and the use of brand-new equipment. Lower levels of contamination of colostrum samples were found in phase 2 (TBC: −0.92 log [±0.19], P < 0.001; TCC: −1.14 log [±0.30], P < 0.001), associated with good operator hygiene practices. Significant correlations (Spearman's rho, rs) were observed between visual cleanliness scores and RLU values from both swabbing techniques, as well as between ATP-L RLU values and bacterial counts (TBC: rs = 0.744, 95% CI: 0.556–0.859, P < 0.0001; TCC: rs = 0.475, 95% CI: 0.183–0.690, P < 0.002). Based on ATP-L swab results, optimal luminometry cutpoints maximizing both sensitivity and specificity were identified at ≥6,950 RLU (sensitivity: 79.17%; specificity: 100%) for TBC, and ≥11,912 RLU (sensitivity: 88.89%; specificity: 70.97%) for TCC. This study demonstrates that targeted hygiene improvements can significantly reduce both equipment surface and colostrum bacterial contamination and support the use of ATP luminometry as a practical tool for hygiene monitoring on dairy farms
Effect of a wireless temperature/ pressure sensor location during inpackaged food microwave heating
No full textInternational audienceThis study focuses on a lab-scale 915 MHz MW heating process for mashed potato inside a polypropylene (PP) tray. The objective is to evaluate the influence of the position of an on-board wireless T and P sensor placed inside the PP tray on the electromagnetic field distribution within a single-mode MW applicator. Experimentally, the sensor (TMI Orion, PicoVACQ PT 15 Bar 4 Hz 3rd generation) is protected within a 316L stainless steel MW shield which looks like an ogive-shaped material (23 mm diameter, 58 mm long). The metallic shield is placed at the centre of the upper surface of a mashed potato sample (300 g). COMSOL ® Multiphysics 6.3 (RF module) is used to predict the electromagnetic field within the MW cavity associated with the MW absorbed power within mashed potato. The model takes into account all the geometrical details of the MW apparatus (waveguide transition, MW applicator with PP tray and metallic MW shield, sliding short circuit …). The microwave input power source is modelled with a coaxial port at the microwave antenna (port 1). All surfaces of the waveguide, including the copper sliding short circuit, are considered as perfect electric conductors (n × E = 0). The dielectric properties of mashed potato (76 % water wet basis) are considered as constant with ' = 45 and '' = 12 (issued from experimental measurements). For the solver settings, boundary mode analysis is used as a first step to compute the mode at port 2 that comes out of the waveguide (chimney beyond its height). The second step is a frequency stationary study at 915 MHz. Without sensor inside the tray, COMSOL ® simulation reveals microwave reflected power of 24 % (S11 = -6.16 dB) with optimal sliding short circuit position at 790 mm. S11 is then evaluated as a function of varying MW shield positions following different rotations from = 0 to 180° with 30° increment. Results indicate that S11 is fluctuating from -4.7 dB to -7.8 dB (33 to 17% MW reflected power). Results show that the MW shield position needs to be aligned to the MW propagation direction ( = 0°) to obtain similar S11 parameter as for the food tray without the sensor (S11 ≈ -6 dB, RF ≈ 24%). Significant reduction of the microwave reflected power (S11 = -7.8 dB, RF = 17%) can be obtained if position of the MW shield (following the cylinder height) is located within the transverse electric plane of the TE10 waveguide ( = 90°). This numerical model helps to find the best position for the sensor to limit its interaction with the electromagnetic field.</div
Utilisation des organoïdes intestinaux porcins pour l'étude des virus entériques porcins
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Towards the possibility for CO2 electroreduction and valorization in low-carbonate concentration solutions? A case study in wastewater treatment application
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Impact of dough mixing pressure with Air and CO2 gases on dough and bread properties
No full textInternational audienceThis study investigated the effect of controlling headspace pressure and gas atmosphere during dough mixing on dough aeration and bread quality. Using a specialized mixer, doughs were mixed with either air or CO 2 under atmospheric pressure and 0.5 bar gauge pressure. Dough aeration (void fraction) was monitored at key breadmaking stages; end of mixing, after sheeting and after fermentation with a target final void fraction of 0.75 for optimal bread volume. A predictive model estimated the expansion ratio needed to achieve this target void fraction. Although the target was not fully reached post-fermentation, doughs mixed with air at 0.5 bar gauge pressure demonstrated a higher ε F = 0.64 and SV of 4.54 cm 3 /g compared to those mixed with CO 2 at the same elevated pressure (ε F = 0.60 & SV = 3.55 cm 3 /g). Lower SV and larger, irregular gas bubbles in CO 2 doughs were attributed to gas bubble disproportionation and loss during sheeting, as well as the weakening of the gluten network due to oxygen depletion. The calculated N required to reach the target void fraction was slightly lower for air (3.20 ± 0.06) than for CO 2 (3.36 ± 0.06), suggesting more efficient gas retention and dough expansion under air-enriched conditions. These finding suggest that while CO 2 may stabilize gas bubbles during mixing, oxygen from air is essential for a strong gluten network and uniform breadcrumb structure. Controlling the mixing atmosphere and pressure, offer a promising approach for optimizing dough aeration and bread quality</div
Effet de l'hyperglycémie maternelle et de la composition du lait sur la programmation métabolique hépatique et pancréatique de la descendance : étude expérimentale chez le rat
No full textInternational audienceBackground: Gestational diabetes (GDM) is a major risk factor for metabolic programming in offspring, increasing their vulnerability to type 2 diabetes (T2D) and metabolic dysfunction-associated fatty liver disease (MASLD). While the benefits of breastfeeding are well established, their modulation in the context of GDM remains poorly studied. Objectives: To evaluate the impact of breast milk composition associated with maternal hyperglycemia on pancreatic β-cell maturation and hepatic homeostasis in offspring according to their sex. Methods: In accordance with Directive 2010/63/EU and the 3Rs, a mouse model of GDM was developed by exposure to a high-fat, high-sugar (HFHS) diet, either restricted to gestation (4HFHS) or extended to lactation (7HFHS), compared to a euglycemic control group (CTL). Cross-fostering at birth allowed the effects of gestation to be dissociated from those of lactation. Milk was characterized at LD1 and LD14 (metabolome and lipidome). The impact on offspring was assessed at different ages (birth, PD8, PND14, PND220 in response to a Western diet) using metabolic tests (oral glucose tolerance test (OGTT), euglycemic-hyperinsulinemic clamp, body composition), gene expression analyses (pancreas, liver), and plasma metabolome. Results: Colostrum from GDM mothers, particularly 7HFHS, was enriched in long-chain sphingolipids. At birth, GDM offspring had β-cell hyperplasia. At PND14, those breastfed by 7HFHS mothers showed overexpression of pancreatic genes (NeuroD1, GLUT2, insulin) and fasting hyperglycemia. In adulthood, GDM offspring breastfed by CTL mothers showed impaired glucose tolerance (males) and reduced insulin sensitivity (females), associated with hepatic dysregulation (incomplete fatty acid oxidation (FAO), increased FETUA). Conversely, nursing by 4HFHS mothers improved certain metabolic markers, particularly in females (complete FAO, reduced gluconeogenesis and lipogenesis, decreased FETUA). Conclusions: Maternal glucose tolerance during the perinatal period influences milk composition and the metabolic trajectory of offspring. These effects, with gender-specific characteristics, highlight breastfeeding as a key period for modulating the postnatal risk of MASLD and T2D, opening up avenues for targeted nutritional intervention