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Céréales pérennes : quelle place pour le Kernza dans les exploitations françaises ?
No full textNational audienceLe Kernza est une graminée fourragère sélectionnée pour son potentiel grain. Dans un contexte rendu incertain par les transformations rapides qu’exige l’adaptation au changement climatique, elle suscite une curiosité croissante chez les agriculteurs français. Le réseau national d’observation du Kernza, qui étudie au champ les modalités de son introduction en France, livre ses premiers enseignements
Major transcriptomic, epigenetic and metabolic changes underlie the pluripotency continuum in rabbit preimplantation embryos
No full textInternational audienceDespite the growing interest in the rabbit model for developmental and stem cell biology, the characterization of embryos at the molecular level is still poorly documented. We conducted a transcriptome analysis of rabbit preimplantation embryos from E2.7 (morula stage) to E6.6 (early primitive streak stage) using bulk and single-cell RNA-sequencing. In parallel, we studied oxidative phosphorylation and glycolysis, and analysed active and repressive epigenetic modifications during blastocyst formation and expansion. We generated a transcriptomic, epigenetic and metabolic map of the pluripotency continuum in rabbit preimplantation embryos, and identified novel markers of naive pluripotency that might be instrumental for deriving naive pluripotent stem cell lines. Although the rabbit is evolutionarily closer to mice than to primates, we found that the transcriptome of rabbit epiblast cells shares common features with those of humans and non-human primates
OPALE: Operational assessment of landscape water eco-functionalities
No full textInternational audienceThe present article proposes a suite of programs aimed at (i) representing landscape organization in relation with the functioning of annual crops or breeding systems, (ii) evaluating water movements from biomass and hydrological exchanges, and (iii) analyzing the transfer dynamics of nutrients, suspended matter or fecal bacteria based on particle tracking methods. Simulations provided indications about the underlying processes that drive exchanges and sink-source effects operating at the landscape scale. OPALE was tested in three agricultural contexts and biophysical situations. Water flows and flows of associated matters were compared to data recorded at the catchment outlet, and showed the efficiency of the algorithms developed in the generic OPALE libraries. This article describes the underlying hypotheses and the full mathematical framework and procedures used to assess landscape eco-functionality. Several examples are given to illustrate the use of OPALE in landscape reconfiguration prospects (e.g. influence of landscape composition and structure on plant transpiration, stream flow, erosion, nutrient and organism fluxes in water) for the agroecological transition
Generation of embryo chimeras with pluripotent stem cells in non-human primates.
No full textNational audienceIn contrast to rodent pluripotent stem cells (PSCs), which self-renew in the naïve state of pluripotency, conventional non-human primate PSCs (NHP-PSCs) self-renew in the primed state of pluripotency. As a result, they are unable to colonise pre-implantation embryo to form somatic chimeras. We developed an original strategy to reprogram NHP-PSCs to naïve-like pluripotency using LIF, Activin, and chemical inhibitors of PKC and WNT signalling. The resulting cells, called 2CLA, acquired gene expression profile closer to the pluripotent cells of primate embryos. To study chimeric competency, NHP 2CLA cells expressing constitutive GFP were injected into morula-stage rabbit and cynomolgus monkey embryos. The reconstituted embryos were cultured to the late blastocyst stage. While conventional NHP-PSCs (prior to reprogramming) returned only 20% of positive embryos harbouring less than 10 GFP+ cells (n = 15), 90% of rabbit blastocysts analysed displayed 10 to 50 GFP+ cells in the epiblast and trophoblast after injection of naïve-like cells. Similar results were obtained after injection of NHP-PSCs into cynomolgus monkey embryos. Thus, after reprogramming to naïve-like pluripotency, NHP-PSCs acquire competence to colonise the epiblast and trophoblast in interspecies chimaeras. Chimeric embryos are currently undergoing single-cell RNA-seq analysis to characterize the phenotype of injected NHP 2CLA cells. This work will lead to better understand the mechanisms involved in chimera generation for studying primate development
Effect of pectin on the properties of nanoemulsions stabilized by sodium caseinate at neutral pH
No full textInternational audienceThe effect of different concentrations of low methoxyl pectin (LMP) on lipid oxidation and physical stability of sodium caseinate (CAS) stabilized nanoemulsions under neutral pH was investigated. The addition of pectin at low concentration (≤ 0.10 wt%) had no significant effect on the average size of nanoemulsions, but a slight size increase and phase separation were observed at higher concentrations of pectin (≥ 0.25 wt%). This result suggests that LMP can not adsorb at the oil/water interfacial CAS membrane at neutral pH. However, in the presence of LMP, the physical stability of nanoemulsions against high salt concentrations and freeze-thaw cycles was significantly enhanced. Moreover, nanoemulsions containing pectin have a better ability to inhibit lipid and protein oxidation than nanoemulsions without pectin after 3 weeks, and the lowest lipid hydroperoxide content was observed for nanoemulsions containing 0.25 wt% pectin
Les services écosystémiques rendus par les agricultures urbaines
No full textchapitre de l'ouvrage de notice https://hal.archives-ouvertes.fr/hal-03829916International audienc
What do we know today about cultured muscle to produce meat and its acceptability in the world?
No full textInternational audienceThe aim of this chapter is to take stock of current knowledge on the potential benefits and weaknesses of cultured muscle to produce meat. Made from stem cells or proliferating muscle cells, cultured “meat” has been presented by its supporters, who are mainly private actors (start-ups), as a food similar to “conventional” meat but more sustainable, even if strong scientific arguments are lacking to support this assessment. There is no consensus about its sanitary and nutritional qualities for human consumption and about its low potential environmental impact. In addition, many issues of market, legislation, ethics, and consumer perception remain to be overcome
Harvesting practices and their influence on soil macrofauna in cocoa-based agroforestry systems
No full textSource Agritrop Cirad (https://agritrop.cirad.fr/606611/)International audienceAgroecological approaches require a complete understanding of the agroecosystems by considering complex and countless interactions. Agroforestry systems, that combine at least one ligneous perennial with at least one crop or cattle species, often aim at optimizing ecological and economical interactions among their components. They encompass highly contrasted agroecosystems, from mechanized input-intensive plantations intercropping only two species to family grown, highly diverse and ecologically intensive agroforests. Cocoa-based agroforestry systems have been widely described in the literature for the high taxonomic and functional diversity of the soil biota, especially of larger-sized organisms such as earthworms and macroinvertebrates. However, the interactions between farmer's practices and soil macrofauna are poorly documented. A common practice all over cocoa producing countries consists in piling the harvested pods on a determined area of the plantation floor before opening them. The cocoa beans are extracted and carried out of the plantations, but pod husks remain on the floor. In this study, we compared pod harvesting sites and sites free of pod husks for the diversity of soil macrofauna in the leaf-litter, the 0-10 cm and the 10 – 20 cm soil layers. Based on 60 soil and leaf litter samples, we compared mature (aged 11-25 years) with old (aged > 70 years) cocoa-based agroforestry plantations in the Dominican Republic. We found that under the cocoa pods, macrofauna density and taxa richness were significantly higher and bulk density was lower. This result is enhanced by the age of the cocoa plantation, as the accumulation of pod husks on a determined harvesting arena tends to be higher over time. The trade-off between a recommendation to spread pod husks over the plantation floor when harvesting cocoa and the current sanitary recommendations for harvesting is discussed