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result(s) for
"Duchene, Olivier"
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Introducing Perennial Grain in Grain Crops Rotation: The Role of Rooting Pattern in Soil Quality Management
by
Duchene, Olivier
,
David, Christophe
,
Barreiro, Ana
in
Agricultural practices
,
Agricultural Science
,
annuals
2020
The use of the perennial grain intermediate wheatgrass (Thinopyrum intermedium (Host) Barkworth & D.R. Dewey) may have the potential to sustain soil health and fertility through the development of an extensive root system. However, references are scarce to demonstrate its potential influence in a context of a limited perennial grain growth phase, integrated into annual grain crops succession. This study aims at determining how early a perennial crop rooting system differs from that of an annual crop through root development and root traits and microbial indicators. Our results indicate that the two-year-old intermediate wheatgrass promotes a denser and deeper rooting system with proportionally more root biomass and length deeper in the soil profile. From the first growing season, the perennial grain demonstrated a suite of root traits typical of a more resource-conservative strategy, and more belowground-oriented resource allocation. Soil fungal biomass indicators were enhanced. Arbuscular mycorrhizal fungi (AMF) indicators were notably found to be improved at 1 m depth during the second growing season. This study provides evidence that grain-based agriculture can benefit from the potential of deeper and long-lived root systems of intermediate wheatgrass to manage soils. The periodic use of a short-term perennial phase in the crop rotation has the potential to improve soil functioning in the long term.
Journal Article
Agronomic assessment of two populations of intermediate wheatgrass—Kernza® (Thinopyrum intermedium) in temperate South America
by
Duchene, Olivier
,
Wang, Zeng‐Yu
,
Gutierrez, Lucia
in
Agricultural production
,
Agronomy
,
Biomass
2022
Background Kernza® intermediate wheatgrass is a perennial grain and forage crop that can provide several ecosystem services. Major research efforts focused on Kernza have taken place in high latitudes. The goal of this study was to evaluate, for the first time, the agronomic performance of Kernza in a low‐latitude region with mild winters. Methods A KS‐cycle 4 Kernza population (A) was planted in spring in Wisconsin, USA, and selected in one cycle for lower vernalization requirements, obtaining a new population (B). These two populations, at three nitrogen (N) fertilization rates, were evaluated in a full factorial, completely randomized field experiment in Uruguay over 2 years. Results The populations were similar in grain yields and flowering time in the 1st year, but population B had 63% lower grain yield in the 2nd year and 20% lower forage yield throughout the experiment. Increasing the N rate to 160 kg ha−1 led to a 63% increase in grain yield and 28% increase in forage yield across populations. Forage yields and nutritive values were similar to those reported in the northern hemisphere. However, grain yields for both the 1st (316 kg ha−1) and 2nd year (41 kg ha−1) were lower due to reduced flowering and weed competition. Conclusions Expansion of Kernza to lower‐latitude regions will require further breeding to improve reproductive performance. Kernza® is a dual‐purpose (grain and forage) perennial crop developed in high latitudes. In a field experiment carried out in a low‐latitude region, high forage yields and high nutritive value were obtained, but grain yields were low, possibly because the vernalization requirements of the species were not completely fulfilled.
Journal Article
Conservation tillage influences soil structure, earthworm communities and wheat root traits in a long-term organic cropping experiment
by
Cadiergues, Adeline
,
Environnement Méditerranéen et Modélisation des Agro-Hydrosystèmes (EMMAH)
,
Ducasse, Vincent
in
Agricultural practices
,
Agricultural sciences
,
Agriculture
2024
Background and Aims: Organic farmers are showing increasing interest in using conservation tillage to improve the biological activities of soils. Here, we assessed whether conservation tillage in organic farming improves earthworm populations, root growth and soil physical quality in a sandy loam after 16 years of experiment. Methods: We compared the effect of a tillage gradient, with of two non-ploughed treatments (superficial tillage [ST] at 15 cm; very superficial tillage [VST] at 5–7 cm) and two ploughed treatments (moldboard ploughing [MP] at 30 cm; shallow moldboard ploughing [SMP] at 20 cm). Soil clod types, penetration resistance, abundance and activity of earthworms, root traits and biomass were assessed. Results: VST decreased soil compaction in topsoil (0 to 10 cm) compared to ploughed treatments (MP and SMP), but led to more compacted soil at 15 to 30 cm. Earthworm biomass (especially anecic) was higher under VST compared to MP and SMP and their galleries were better connected to the soil surface. However, there was no significant difference in the total volume of pores or diameter of galleries between 0 and 30 cm. Soil compaction in the non-ploughed treatments affected root traits, especially under VST, with lower specific root length, higher root diameter, and lower root tip elongation compared to MP and SMP. Conclusion: Biological activity did not compensate for the compaction of a sandy soil after 16 years without ploughing in organic farming. A more integrated approach (i.e. considering all 5 soil health principles) is needed to sustain soil health and functions, and meet current expectations about “ecological intensification”.
Journal Article
Introducing intermediate wheatgrass as a perennial grain crop into farming systems: insights into the decision-making process of pioneer farmers
by
Duchene, Olivier
,
David, Christophe
,
Ginot, Christelle
in
Agricultural production
,
Agricultural sciences
,
Agriculture
2024
The perennial grain intermediate wheatgrass (
Thinopyrum intermedium
, commercial name Kernza
TM
) has been proposed as a diversification crop for producing forage and grain and providing ecosystem services to farmers. Although a few studies have addressed farmers’ interests in the crop, information is lacking about the links between farmers’ goals and crop management, i.e., how farmers aim at integrating this crop in their systems. Closing this gap, this paper analyzes for the first time the introduction of intermediate wheatgrass (IWG) from a farmer perspective, as a set of decision plans and goals. The overarching orientations of the farm and organization of the production system, referred as strategic decisions, interact with short-term crop management (i.e., tactical decisions) and farmers’ goals for IWG. In total, 17 individual semi-structured interviews and 2 collective crop management prototyping workshops in France were used to analyze farmers’ rationales as a function of their farm systems, agronomic constraints, and know-how. The study demonstrates that farmers’ interests in IWG revolved around multiple ecosystem services and financial returns. Three ideal-types of farms testing IWG emerged from the relationships between existing farming systems and goals for IWG. The strategic and tactical decisions regarding the integration and management of IWG were contingent on the farming systems, the goals for IWG, the farmers’ know-how, and their ability to mitigate risks. Implications for the future development of intermediate wheatgrass as a niche innovation are considered based on farmers’ points of view. This study provides insights into the ideas and concerns of French farmers regarding IWG and proposes a framework for discussing the introduction of a new crop in a farm system.
Journal Article
Mechanical properties of rubble pile asteroids (Dimorphos, Itokawa, Ryugu, and Bennu) through surface boulder morphological analysis
by
Trigo-Rodriguez, Josep M.
,
Stott, Alexander
,
Rivkin, Andrew S.
in
639/33/445/215
,
639/33/445/848
,
704/445/848
2024
Planetary defense efforts rely on estimates of the mechanical properties of asteroids, which are difficult to constrain accurately from Earth. The mechanical properties of asteroid material are also important in the interpretation of the Double Asteroid Redirection Test (DART) impact. Here we perform a detailed morphological analysis of the surface boulders on Dimorphos using images, the primary data set available from the DART mission. We estimate the bulk angle of internal friction of the boulders to be 32.7 ± 2. 5° from our measurements of the roundness of the 34 best-resolved boulders ranging in size from 1.67–6.64 m. The elongated nature of the boulders around the DART impact site implies that they were likely formed through impact processing. Finally, we find striking similarities in the morphology of the boulders on Dimorphos with those on other rubble pile asteroids (Itokawa, Ryugu and Bennu). This leads to very similar internal friction angles across the four bodies and suggests that a common formation mechanism has shaped the boulders. Our results provide key inputs for understanding the DART impact and for improving our knowledge about the physical properties, the formation and the evolution of both near-Earth rubble-pile and binary asteroids.
Planetary Defense efforts rely on estimates of asteroids’ mechanical properties, which are difficult to obtain accurately from Earth. Here, authors compare images from space missions to the rubble-pile asteroids Dimorphos, Itokawa, Ryugu, and Bennu and study such properties through boulders on their surface.
Journal Article
Short-lived active margin magmatism preceding Variscan collision in the western French Massif Central
by
Baele, Jean-Marc
,
Benoit, Mathieu
,
Benmammar, Anissa
in
absolute age
,
active margins
,
alkaline earth metals
2024
This paper presents and discusses new geochronological and petrological data on a suite of calc-alkaline plutons composed predominantly of diorites and tonalites from the West Massif Central. Their petrochemical fingerprints are compatible with partial melting of a hydrous mantle wedge followed by fractional crystallization of amphibole and plagioclase before final emplacement between 5 and 8 kbar within the continental upper plate of a subduction system. In situ U-Pb zircon dating on tonalites yields a fairly narrow age range of 365-354 Ma (including uncertainties) for igneous crystallization. These calc-alkaline plutons imply active margin magmatism near the Devonian-Carboniferous boundary and are contemporaneous with the back-arc magmatism and HP metamorphism as dated by recent studies. However, such isolated igneous bodies do not form a transcrustal magmatic arc but rather represent dispersed plutons emplaced within less than 30 Myr when all data from the Variscan belt of France are considered. In Limousin, they intrude migmatitic paragneisses and retrogressed eclogites from the Upper Gneiss Unit (UGU), suggesting that the high pressure rocks were already exhumed at 19-30 km depth before 365 Ma. Moreover, the diorites and tonalites are never found within units below the UGU. It therefore suggests that these tectono-metamorphic units of the Western French Massif Central were piled up after 354 Ma. Altogether these results support the monocyclic model for Variscan geodynamics in the French Massif Central, with the transition between oceanic subduction and continental collision taking place between Upper Devonian and Lower Carboniferous.
Journal Article
Pressure-temperature conditions and significance of Upper Devonian eclogite and amphibolite facies metamorphisms in southern French Massif central
by
Baele, Jean-Marc
,
Bendaoud, Abderrahmane
,
Benmammar, Anissa
in
Continental margins
,
Crystallization
,
Devonian
2020
The southwestern French Massif central in western Rouergue displays an inverted metamorphic sequence with eclogite and amphibolite facies units forming the top of the nappe stack. They are often grouped into the leptyno-amphibolite complex included, in this area, at the base of the Upper Gneiss Unit. We sampled garnet micaschists and amphibolites to investigate their metamorphic history with isochemical phase diagrams, thermobarometry and U-Pb zircon dating. Our results demonstrate that two different tectono-metamorphic units can be distinguished. The Najac unit consists of biotite-poor phengite-garnet micaschists, a basic-ultrabasic intrusion containing retrogressed eclogites and phengite orthogneisses. Pressure and temperature estimates on micaschists with syn-kinematic garnets yield a prograde with garnet growth starting at 380 °C/6–7 kbar, peak pressure at 16 kbar for 570 °C, followed by retrogression in the greenschist facies. The age of high pressure metamorphism has been constrained in a recent publication between ca. 383 and 369 Ma. The Laguépie unit comprises garnet-free and garnet-bearing amphibolites with isolated lenses, veins or dykes of leucotonalitic gneiss. Thermobarometry and phase diagram calculation on a garnet amphibolite yield suprasolidus peak P-T conditions at 710 °C, 10 kbar followed by retrogression and deformation under greenschist and amphibolite facies conditions. New U-Pb analyses obtained on igneous zircon rims from a leucotonalitic gneiss yield an age of 363 ± 3 Ma, interpreted as the timing of zircon crystallization after incipient partial melting of the host amphibolite. The eclogitic Najac unit records the subduction of a continental margin during Upper Devonian. It is tentatively correlated to a Middle Allochthon, sandwiched between the Lower Gneiss Unit and the Upper Gneiss Unit. Such an intermediate unit is still poorly defined in the French Massif central but it can be a lateral equivalent of the Groix blueschists in the south Armorican massif. The Uppermost Devonian, amphibolite facies Laguépie unit correlates in terms of P-T-t evolution to the Upper Gneiss Unit in the Western French Massif central. This Late Devonian metamorphism is contemporaneous with active margin magmatism and confirms that the French Massif central belonged to the continental upper plate of an ocean-continent subduction system just before the stacking of Mississippian nappes. Les unités tectono-métamorphiques du sud-ouest du Massif central français, dans l’ouest du Rouergue, sont structurées selon une séquence métamorphique inverse où les unités du faciès éclogite et amphibolite se situent au sommet de l’empilement des nappes. Ces unités régionales sont généralement incorporées dans le complexe leptyno-amphibolique, formant la base de l’Unité des Gneiss Supérieurs. Suite à une étude comparative de l’histoire métamorphique des unités de Najac et de Laguépie, deux unités tectono-metamorphiques peuvent etre distinguées. L’unité de Najac est composée de métapélites à phengite-grenat pauvres en biotite, d’une intrusion basique-ultrabasique renfermant des éclogites rétromorphosées et des orthogneiss à phengite. Le grenat commence sa croissance vers 380 °C/6–7 kbar, suivi d’un pic de pression à 16 kbar et 570 °C et enfin d’une rétromorphose dans les conditions du faciès des schistes verts. L’âge du métamorphisme de haute-pression a été contraint récemment entre 383 et 369 Ma. L’unité de Laguépie est formée par des amphibolites avec ou sans grenat renfermant des lentilles isolées, des veines ou dykes de gneiss leucotonalitique. Les conditions P-T ont été estimées sur une amphibolite à grenat à 710 °C et 10 kbar pour la fusion partielle suivie d’une rétromorphose et une déformation dans les conditions du faciès des amphibolites et des schistes verts. Les datations U-Pb sur des bordures de zircons d’une veine de gneiss leucotonalitique donnent un âge de 363 ± 3 Ma, interprété comme marquant la cristallisation magmatique des zircons après l’initiation de la fusion partielle de l’encaissant amphibolitique. L’unité de Najac a enregistré la subduction d’une marge continentale au Dévonien supérieur. Elle peut être corrélée à un Allochthone Intermédiaire, compris entre l’Unité des Gneiss Inférieurs et l’Unité des Gneiss Supérieurs. Une telle unité intermédiaire est encore mal définie dans le Massif central français mais elle peut être un équivalent latéral des schistes bleus de Groix dans le Massif Armoricain. L’unité amphibolitique du Dévonien Supérieur de Laguépie est reliée en termes d’évolution P-T-t à l’Unité des Gneiss Supérieurs dans le Massif Central français occidental. Ce métamorphisme du Dévonien tardif est contemporain d’un magmatisme de marge active et confirme que le sud du Massif Central français appartenait à la plaque continentale supérieure d’un système de subduction océan-continent juste avant l’empilement des nappes durant le Mississippien.
Journal Article
The kinase domain of TRPM7 interacts with PAK1 and regulates pancreatic cancer cell epithelial-to-mesenchymal transition
2025
Pancreatic ductal adenocarcinoma (PDAC) is the main and the deadliest form of pancreatic cancer. This is a major problem of public health since it will become the second leading cause of death by cancer in the next few years, mainly due to the lack of efficient therapies. Transient Receptor Potential Cation Channel Subfamily M Member 7 (TRPM7) protein, a cation channel fused with a serine/threonine kinase domain is overexpressed in PDAC and associated with a low survival. In this work, we aim to study the role of kinase domain on pancreatic cell fates by using a model of kinase domain deletion by CRISPR-Cas9. PANC-1 and MIA PaCa-2 PDAC cell lines were used and kinase domain was deleted by CRISPR-Cas9 strategy. Kinase domain deletion (ΔK) was validated by RT-qPCR and western blots. The effect of kinase domain deletion on channel function was studied by patch-clamp and Mn
2+
-quenching. The cell phenotype was studied by MTT and cell migration/invasion assays. Finally, the role of kinase domain was studied in vivo in xenografted mice. Here we show that TRPM7 kinase domain is required to maintain a mesenchymal phenotype in PDAC cells. We also demonstrated that TRPM7 and PAK1 interact in the same protein complexes. Moreover, TRPM7 kinase domain is required for carcinogenesis and cancer cell dissemination in vivo. Intriguingly, the role of TRPM7 kinase is cell specific and may depend on the KRAS oncogene mutation status. In conclusion, TRPM7 kinase domain is required to maintain a mesenchymal and aggressive phenotype in PDAC cells, and it could be a promising target against PDAC.
Journal Article
Anthropomorphic Breast and Head Phantoms for Microwave Imaging
by
Duchêne, Bernard
,
Joachimowicz, Nadine
,
Conessa, Christophe
in
Additive manufacturing
,
Anthropomorphism
,
Bioengineering
2018
This paper deals with breast and head phantoms fabricated from 3D-printed structures and liquid mixtures whose complex permittivities are close to that of the biological tissues within a large frequency band. The goal is to enable an easy and safe manufacturing of stable-in-time detailed anthropomorphic phantoms dedicated to the test of microwave imaging systems to assess the performances of the latter in realistic configurations before a possible clinical application to breast cancer imaging or brain stroke monitoring. The structure of the breast phantom has already been used by several laboratories to test their measurement systems in the framework of the COST (European Cooperation in Science and Technology) Action TD1301-MiMed. As for the tissue mimicking liquid mixtures, they are based upon Triton X-100 and salted water. It has been proven that such mixtures can dielectrically mimic the various breast tissues. It is shown herein that they can also accurately mimic most of the head tissues and that, given a binary fluid mixture model, the respective concentrations of the various constituents needed to mimic a particular tissue can be predetermined by means of a standard minimization method.
Journal Article