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Trace element fluxes linked to organic waste recycling as fertilizing practice: potential risks? Usefulness of long-term field experiments
No full textEffet du moment d'acquisition des spectres proche infrarouge sur la qualité de prédiction du taux de lipides et du taux de fonte du foie gras chez le canard
No full textPour caractériser la composition biochimique des tissus animaux,la spectrométrie proche infrarouge (SPIR) est de plus en plus utilisée. Des études précédentes sur le foie gras ont montré la capacité de prédire le taux de lipides et le taux de fonte. L’objectif de ce travail est d’étudier l’effet du moment d’acquisition des spectres sur la qualité de prédiction de ces deux grandeurs. Des spectres infrarouges ont été acquis deux fois sur les mêmes foies gras, en post éviscération (PE) et en post refroidissement (PEPR). Les données spectrales ont été collectées en réflectance (R) dans les régions du visible et du PIR (350-2500 nm, pas de 1 nm) avec un spectromètre portable LabSpec® 5000 (ASD Inc., Boulder (CO), USA) équipé d'un module de contact. Le taux de fonte à la cuisson (n=182) et le taux de lipides (n=125) ont été mesurés. Chacun des groupes de spectres PE et PEPR ont été séparés en deux jeux de données, un jeu de calibration (2/3 des échantillons) et un jeu de validation afin d’établir des équations de prédiction de la composition des foies. Les deux jeux de calibration ainsi que les deux jeux de validation ont aussi été regroupés afin d’établir une équation de prédiction globale. Le traitement des spectres et le développement des équations de prédiction ont été réalisés avec le logiciel WinISI (version 4.6.8, FOSSAnalytical A/S, Hilleroed, Danemark) sur une fenêtre de 650 à 2350 nm. Les équations de prédiction ont été établies par régression partielle des moindres carrés (mPLS du logiciel WinISI) après transformation des données par une Standard Normal Variate andDetrend (SNVD) avec une dérivée première et un lissage de 10 (1/10/10/1).Les équations développées avec les spectres acquis en post éviscération permettent de prédire le taux de fonte et le taux de lipides des foies dont les spectres ont été acquis au même moment post-mortem, mais ne permettent pas de prédire ces grandeurs pour des spectres acquis en post refroidissement. Des résultats similaires ont été obtenus sur les spectres en post refroidissement. En outre, les équations développées sur l’ensemble des spectres disponibles ont une qualité de prédiction équivalente à celles citées précédemment. Ainsi, il est possible de rassembler des spectres acquis à différents moments post mortem et de faire une seule équation afin de prédire soit le taux de lipidesdes foies soit leur taux de font
Produire des légumineuses à graines au moyen de l’association avec une céréale : cas de la lentille et du lupin blanc d’hiver
No full textGrain legumes provide numerous nutritional, agronomic and environmental benefits and are at the core of the sustainability challenges of agricultural systems. Yet, grain legumes are hardly cultivated in Europe, not least because of strong agronomic constraints that reduce their yields and increase yield instability. Two PhD theses were performed to 1) assess the potential of intercropping cereals (wheat, triticale) with grain legumes (lentil and winter white lupin) to reduce the impacts of agronomic constraints on legume production; 2) better understand the functioning of these intercrops to improve their agronomic and economic performances.
Intercropping legumes with a low density of cereal increased total grain yield in almost all tested situations compared to sole crops. The better global performance of intercrops was mainly due to a higher acquisition of light and nitrogen resources resulting from complementarities between species within the intercrops. Moreover, the presence of the cereal reduced weed biomass and lentil lodging. Intercropping legumes with cereals is thus a suitable agricultural practice to foster grain legume production in Europe
A New Prevalent Densovirus Discovered in Acari. Insight from Metagenomics in Viral Communities Associated with Two-Spotted Mite (Tetranychus urticae) Populations : Metagenomics in Viral Communities Associated with Two-Spotted Mite ([i]Tetranychus urticae[/i]) Populations
No full textViral metagenomics and high throughput sequence mining have revealed unexpected diversity, and the potential presence, of parvoviruses in animals from all phyla. Among arthropods, this diversity highlights the poor knowledge that we have regarding the evolutionary history of densoviruses. The aim of this study was to explore densovirus diversity in a small arthropod pest belonging to Acari, the two-spotted spider mite Tetranychus urticae, while using viral metagenomics based on virus-enrichment. Here, we present the viromes obtained from T. urticae laboratory populations made of contigs that are attributed to nine new potential viral species, including the complete sequence of a novel densovirus. The genome of this densovirus has an ambisens genomic organization and an unusually compact size with particularly small non-structural proteins and a predicted major capsid protein that lacks the typical PLA2 motif that is common to all ambidensoviruses described so far. In addition, we showed that this new densovirus had a wide prevalence across populations of mite species tested and a genomic diversity that likely correlates with the host phylogeny. In particular, we observed a low densovirus genomic diversity between the laboratory and natural populations, which suggests that virus within-species evolution is probably slower than initially thought. Lastly, we showed that this novel densovirus can be inoculated to the host plant following feeding by infected mites, and circulate through the plant vascular system.
These findings offer new insights into densovirus prevalence, evolution, and ecology
The ribosome as a missing link in prebiotic evolution III: over-representation of tRNA- and rRNA-like sequences and plieofunctionality of ribosome-related molecules argues for the evolution of primitive genomes from Rrbosomal RNA Modules
No full textWe propose that ribosomal RNA (rRNA) formed the basis of the first cellular genomes, and provide evidence from a review of relevant literature and proteonomic tests. We have proposed previously that the ribosome may represent the vestige of the first self-replicating entity in which rRNAs also functioned as genes that were transcribed into functional messenger RNAs (mRNAs) encoding ribosomal proteins. rRNAs also encoded polymerases to replicate itself and a full complement of the transfer RNAs (tRNAs) required to translate its genes. We explore here a further prediction of our ribosome-first theory: the ribosomal genome provided the basis for the first cellular genomes. Modern genomes should therefore contain an unexpectedly large percentage of tRNA- and rRNA-like modules derived from both sense and antisense reading frames, and these should encode non-ribosomal proteins, as well as ribosomal ones with key cell functions. Ribosomal proteins should also have been co-opted by cellular evolution to play extra-ribosomal functions. We review existing literature supporting these predictions. We provide additional, new data demonstrating that rRNA-like sequences occur at significantly higher frequencies than predicted on the basis of mRNA duplications or randomized RNA sequences. These data support our ribosome-first theory of cellular evolution
Evaluer les services rendus par un atelier volailles avec parcours : proposition du cadre conceptuel Bouquet
No full textEffect of water gradient on the intensity of competition and productivity of annual crops intercropped with olive trees
No full textEfficiency optimization of CRISPR/Cas9-mediated targeted mutagenesis in grape
No full textClustered regularly interspersed short palindromic repeats (CRISPR)/Cas system is an efficient targeted genome editing method. Although CRISPR/Cas9-mediated mutagenesis has been applied successfully in grape, few studies have examined the technique's efficiency. To optimize CRISPR/Cas9 editing efficiency in Vitis vinifera, we surveyed three key parameters: GC content of single guide RNA (sgRNA), variety of transformant cells used, and SpCas9 expression levels in transgenic cell mass. Four sgRNAs with differing GC content were designed to target exon sites of the V. vinifera phytoene desaturase gene. Suspension cells of 'Chardonnay' and '41B' varieties were used as the transgenic cell mass. Both T7EI and PCR/RE assays showed that CRISPR/Cas9 editing efficiency increases proportionally with sgRNA GC content with 65% GC content yielding highest editing efficiency in both varieties. Additionally, gene editing was more efficient in '41B' than in 'Chardonnay.' CRISPR/Cas9 systems with different editing efficiency showed different SpCas9 expression level, but compared with GC content of sgRNA, SpCas9 expression level has less influence on editing efficiency. Taken together, these results help optimize of CRISPR/Cas9 performance in grape
Microbial diversity of Pélardon, an artisanal raw goat milk cheese
No full textArtisanal fermented foods represent a cultural heritage that needs to be preserved and protected; this is particularly true in the context of industrial food standardization. The manufacture and unique sensorial properties of such products mainly relies on autochthonous complex microbiota and their activities. The present study focuses on Pélardon, a Protection Designation of Origin (PDO) French artisanal soft rind cheese, exclusively produced from raw goat’s milk using a back slopping method in mountainous areas in southern France.
Pélardon microbial ecology and dynamics were studied by culture-dependent and -independent methods. A complete production was followed at an artisanal cheese-making factory and sampling was performed at different cheese-making steps from the raw milk to cheese ripened for 3 months. Different population were monitored on different media. Fungal and bacterial isolates were collected and identified. The achieved results were compared to metabarcoding analyses targeting ITS 2 region for Fungi and V3-V4 region of the 16S RNAr for Bacteria.
Focusing on cultivable microorganisms, higher microbial populations were observed in whey used for inoculation compared to raw milk. Results also highlighted the importance of fungi. Despite the initial low inoculum, yeast growth began as early as milk acidification and during the renetting step. Metagenetic results outlined the differences in both fungal and bacterial communities between cheese rind and core samples. Bacterial diversity increased during the
ripening specially in the rind compared to the curd stage. Although yeasts were present early in the processing, fungal diversity remained limited at the end of ripening.
To better understand the origin of the observed microbial diversity, environmental and raw material samples were also investigated and ongoing work should provide new insights about the dynamics of these microbial communities
Mapping of soils and land-related environmental attributes in France: analysis of end-users' needs.
No full textThe 1:250,000 soil mapping program of France is nearly complete. Although mapping has been conducted using conventional methods, there is a discernible need to obtain more precise soil data using other methods, and this is attracting considerable attention. However, it is currently not possible to implement a conventional and systematic program throughout the French territory, as the cost of acquiring new data on a finer scale is too high. In light of this, the Ministry of Agriculture commissioned a national survey to determine the needs of soil mapping in France, which asked questions to soil data producers and end-users. The results presented here summarize the main needs expressed by end-users. The main topics covered by soil mapping applications are identified in addition to the main mismatches between topics currently covered using available soil maps and the needs of end-users. Certain priorities for producing new soil information are identified in relation to geographical environments and settings, soil attributes, the spatial resolution of maps and the use of uncertainty estimates. Digital Soil Mapping is identified as a method that can bridge economic, scientific and practical considerations, but it requires dedicated efforts in order to build capacity. Finally, there is discussion of how the consideration of user needs can be employed to enhance the contribution of a new Digital Soil Mapping era, and to launch an operational soil security paradigm in France