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Relations entre la résistance à la pasteurellose après infection expérimentale et les caractères de croissance et de reproduction mesurés en élevage commercial
No full textLa pasteurellose une maladie bactérienne parmi les plus répandues en élevage cunicole. Le projet RELAPA a pour objectif d’étudier le déterminisme de la résistance à la pasteurellose. Un total de 955 lapins de 6 semaines, issus de 28 mâles appartenant à 6 lignées commerciales, ont été inoculés avec une pasteurelle pyogène et 2 semaines plus tard une note de résistance de 0 à 4 leur a été attribuée après sacrifice. Ces notes ont servi à classer les 28 mâles en 2 groupes,14 résistants et 14 sensibles, d'après la note moyenne de résistance de leur descendance. Par ailleurs ces 28 mâles, dans des élevages commerciaux, ont engendré 5164 lapereaux contrôlés pour leur croissance et 884 femelles reproductrices qui ont elles-mêmes fourni 3568 portées contrôlées. Le seul caractère qui présentait une différence significative entre les descendants de 14 mâles résistants et de14 mâles sensibles était la fertilité, avec une différence de 7 points en faveur du groupe des mâles résistants. Les corrélations résiduelles entre la note de résistance et les caractères de production étaient toutes faibles et non significativement différentes de zéro. Les corrélations génétiques entre la résistance et les caractères pondéraux étaient positives mais non significativement différentes de zéro (0,32 ± 0,51 pour le poids au sevrage et 0,27 ±0,49 pour le poids final). Les corrélations génétiques entre la note de résistance moyenne et les caractères de reproduction étaient défavorables mais non significativement différentes de zéro (-0,43 ± 0,45, -0,68 ± 0,40, 0,70 ± 0,65 respectivement pour le nombre de nés totaux par portée, le nombre de nés vivants par portée et la mortinatalité). Ces valeurs de corrélations génétiques sont données pour information mais elles doivent être interprétées avec beaucoup de prudence car leur précision est très faible
A conserved odorant binding protein is required for essential amino acid detection in Drosophila
No full textAnimals need to detect in the food essential amino acids that they cannot synthesize. We found that the odorant binding protein OBP19b, which is highly expressed in Drosophila melanogaster taste sensilla, is necessary for the detection of several amino acids including the essential l-phenylalanine. The recombinant OBP19b protein was produced and characterized for its binding properties: it stereoselectively binds to several amino acids. Using a feeding-choice assay, we found that OBP19b is necessary for detecting l-phenylalanine and l-glutamine, but not l-alanine or D-phenylalanine. We mapped the cells expressing OBP19b and compared the electrophysiological responses of a single taste sensillum to several amino acids: OBP19b mutant flies showed a reduced response compared to control flies when tested to preferred amino acids, but not to the other ones. OBP19b is well conserved in phylogenetically distant species suggesting that this protein is necessary for detection of specific amino acids in insects
Développer des actions pour (ré-)engager les personnes âgées vivant en EHPAD dans l'acte alimentaire
No full textGenetic, morphological and chemical investigations reveal the genetic origin of Pompia (C. medica tuberosa Risso & Poiteau) - An old endemic Sardinian citrus fruit
No full textCitrus fruits have been introduced to the Mediterranean area from Asia for centuries and spontaneous crosses have generated several hybrid forms, some of which have had agricultural or industrial success while others have remained niche food or ornamental products, or have disappeared. Pompia (C. medial tuberosa Risso & Poiteau) is an old endemic citrus fruit from Sardinia of unknown genetic origin. Initial phenotypic and molecular characterizations revealed a high degree of similarity with lemon (C. limon (L.) Burm.) and citron (C. medico L.). To identify the ancestors of Pompia, 70 citrus species of the Citrus genus were genotyped with 36 codominant molecular markers (SSR and InDel) of nuclear and cytoplasmic genomes. Diversity analysis and allelic comparisons between each citrus species at each locus indicated that Pompia resembles lemon and limonette of Marrakech, i.e. the result of a cross between sour orange (C. aurantium L.) and citron, where citron was the pollinator. Two Italian citron varieties were identified as potential male parents, i.e. Diamante and Common Poncire. However, we were unable to differentiate varieties of sour oranges because varietal diversification in this horticultural group resulted from DNA sequence variations that SSR or InDel markers could not reveal. Rhob el Arsa and Poncire de Collioure were found to be two synonyms of Pompia. Pompia appeared to be equally distinct from citron, lemon and sour orange based on the overall analysis of the fruit, leaf and seed phenotype, and juice chemical composition. At the leaf level, the Pompia essential oil (EO) composition is close to that of citron whereas the zest is much closer to that of sour orange
Model-based estimation of aphid dispersal distances and its use to co-optimize sharka management strategies and the allocation of resistant cultivars
No full textLes attentes des éleveurs, conseillers et formateurs en matière d’information, d’accompagnement et de conseil
No full textEvidence for long‐term prevalence of cucumber vein yellowing virus in Sudan and genetic variation of the virus in Sudan and the Mediterranean Basin
No full textCucumber vein yellowing virus (CVYV) is emerging throughout the Mediterranean Basin, where it causes important damages on cucumber and melon crops. It has been suggested that CVYV originated from the Middle East and has spread only recently to other areas. In this work, an isolate from Sudan was characterized and surveys performed in that country between 1992 and 2012 revealed a long‐term presence of CVYV with a high molecular variability, showing that the virus has long been endemic in Sub‐Saharan Africa. Comparison of the full‐length sequences of 11 CVYV isolates from different geographic origins revealed recombination events in CVYV populations from the Mediterranean Basin and the Middle East, and evidence for different selection pressures along the genome. These results shed a new light on the evolution of CVYV
Optimising observation networks for the early detection and unequivocal attribution of environmental effects on European forests
No full textThe effects of management on vegetation trajectories during the early‐stage restoration of previously arable land after hay transfer
No full textThe restoration of floodplain grasslands has benefited from many studies of the underlying mechanisms. Among the operational tools that resulted, hay transfer is now used increasingly to alleviate the effects of limited seed dispersal and recruitment. To improve this method, we still need to understand how it can affect restoration trajectories, and particularly their direction and magnitude during the early stages of restoration. Based on concepts from the field of community ecology theory, we investigated the effects of early-stage management through grazing or mowing on restoration trajectories after soil harrowing and hay transfer. We established a randomized block design experiment and quantified several community-related metrics to formalize restoration trajectories for 3 years after hay transfer on a previously arable alluvial island in southwestern France. Whatever the management treatment, the species richness and evenness were significantly higher in hay-inoculated than in control plots. This effect was linked to the recruitment of species originating not only from the reference grassland through hay transfer, but also from the seed bank, a well-known effect of soil harrowing. Although generally oriented toward the reference grassland, the origin, direction, and magnitude of the trajectory of hay-inoculated plots all depended on the management applied. Sheep grazing applied at the same time as hay transfer enhanced the recruitment of reference species as from the first experimental year, because it controlled aboveground competition and maintained the window of opportunity open for a sufficiently longer period of time. Our findings show that the type of management applied simultaneously to hay transfer influences the origin of a grassland trajectory, while its direction and magnitude are dependent on the management applied in subsequent years. Grazing immediately after hay transfer may be appropriate to accelerate the recruitment of species from the reference grassland
Co-occurrence of DON and emerging mycotoxins in worldwide finished pig feed and their combined toxicity in intestinal cells
No full textFood and feed can be naturally contaminated by several mycotoxins, and concern about the hazard of exposure to mycotoxin mixtures is increasing. In this study, more than 800 metabolites were analyzed in 524 finished pig feed samples collected worldwide. Eighty-eight percent of the samples were co-contaminated with deoxynivalenol (DON) and other regulated/emerging mycotoxins. The Top 60 emerging/regulated mycotoxins co-occurring with DON in pig feed shows that 48%, 13%, 8% and 12% are produced by Fusarium, Aspergillus, Penicillium and Alternaria species, respectively. Then, the individual and combined toxicity of DON and the 10 most prevalent emerging mycotoxins (brevianamide F, cyclo-(L-Pro-L-Tyr), tryptophol, enniatins A1, B, B1, emodin, aurofusarin, beauvericin and apicidin) was measured at three ratios corresponding to pig feed contamination. Toxicity was assessed by measuring the viability of intestinal porcine epithelial cells, IPEC-1, at 48-h. BRV-F, Cyclo and TRPT did not alter cell viability. The other metabolites were ranked in the following order of toxicity: apicidin > enniatin A1 > DON > beauvericin > enniatin B > enniatin B1 > emodin > aurofusarin. In most of the mixtures, combined toxicity was similar to the toxicity of DON alone. In terms of pig health, these results demonstrate that the co-occurrence of emerging mycotoxins that we tested with DON does not exacerbate toxicity