Utilisation de l'espace pastoral par les caprins en zone aride et semi-aride du Vénézuela

Les troupeaux caprins extensifs en pâturage libre sont une composante importante des systèmes de production paysans des zones arides et semi-arides du Venezuela. Améliorer la gestion collective de l'espace pastoral implique de bien comprendre au préalable les modes d'utilisation des ressources naturelles par les troupeaux, d'identifier les aires de repos (quedaderos), les points d'eau et d'évaluer leur rôle plus ou moins essentiel, suivant la saison, dans l'organisation des déplacements des animaux. Dans la recherche de l'adéquation ressources alimentaires disponibles et besoins des troupeaux, les éleveurs valorisent des ressources complémentaires issues des surfaces cultivées en petites parcelles clôturées : conucos et potreros. La prise en compte du résultat des observations des modes d'utilisation et de gestion de l'espace pastoral et des relations de complémentarité éventuelle avec les surfaces cultivées est nécessaire pour mettre au point toute proposition d'amélioration de gestion des ressources du milieu. (Résumé d'auteur

Produire Bio en montagne et zone défavorisée

Le Thème B est un des six Thèmes prévus et mets à fin dans le projet BIOFEP. Comme le titre du projet BIOFEP (« Comparaison des modes d’organisation, de production et commercialisation des productions animales biologiques en France, Espagne et Portugal ») soutiens, toutes les Thèmes étaient développées en fait l’attention à comparaison entre les trois pays relativement à l’agriculture biologique. Cette comparaison était effectuée ayant pour base l’information disponible en chaque pays et ayant pour base l’information spécialement recueillit pour ce but. Le thème B était développé d’accord les points et respectives objectives initialement prévues, excepte le point sept, qui a été inclus dans les Thèmes relatifs à commercialisation et approvisionnement. Pour chaque point est présentée la méthodologie mise en place pour la récolte d’information de façon à atteindre les respectives objectives y explicités, et les résultats obtenus On a cherché à ce que l’information recueillît et incluse dans ce rapport était accompagnée des « sites » d’Internet, où l’on y pourra consulter d’une façon plus détaillée

The impact of fruit texture and human saliva on the release of aroma compounds using fresh and dried mango samples

Flavour is one of the main factors affecting consumer's food preference. Our aromatic perception is greatly influenced by the release of aroma compounds during consumption itself influenced by the food matrix[1], the human oral physiology and oral processing[2]. In vivo or in vitro techniques were conducted on simple or model matrices to understand impact factors on the release of aroma compounds. However, very few studies were performed on real food matrices as fruits to understand the effect of food matrix and the oral physiology on the release of aroma compounds during oral processing. The present study investigated the impact of fruit texture and human saliva on the release of aroma compounds using in vivo and in vitro tests respectively. Mango was chosen as model fruit because of its richness in aroma compounds and its ability to process it into various products. To obtain different textures, two fresh mango products (puree, cubic pieces) and two dried mango products (powder, cubic pieces) were prepared from a homogenous fruit batch. The aroma compounds of mango samples were extracted by a convenient technique SAFE[3] (Solvent assisted flavour evaporation) and characterized by GC-MS analysis. Among volatile compounds detected, nineteen are considered as potential key flavour compounds from in mango samples. Aroma released during in vivo consumption of mango samples by trained panellists (n=8) was studied using RATD[4] technique (retronasal aroma-trapping device) mounted with Tenax. Volatile compounds trapped on Tenax were further analyzed by GC-MS. Twenty terpenes and one ester were identified in the exhaled nostril breath of panellists. They were amongst major volatile compounds of mango samples. Ten of which were reported as potential key flavour compounds in mango. The in vivo release of volatile compounds was affected by the matrix texture. The intact samples (fresh and dried cubic pieces) released more aroma compounds than disintegrated samples (fresh puree, dried powder). To understand the effect of saliva on aroma release, in vivo experiments with P&T[5] technique (purge and trap, Tenax as adsorbent) were carried out in the presence of saliva collected from the panellists and mango samples in the conditions as closely as possible to those in vivo consumption. The presence of human saliva didn't have a significant effect on the release of aroma compounds. In conclusion, the fruit texture but not saliva seemed to be the main factor in the release of volatile compounds during mango fruit consumption. (Résumé d'auteur

El Proyecto BIOFEP de análisis comparativo, Portugal, España y Francia, de la producción ganadera ecológica en zonas de montaña

Los contactos mantenidos en los arios 2001 y 2002 entre distintas organizaciones de los Pirineos Franceses, el norte de España y la zona norte de Portugal, pusieron en evidencia la existencia de lagunas en la producción ganadera ecológica en zonas de montaña (PGEZM). Esta constatación llevó a plantear un proyecto, de acrónimo BIOFEP, a la convocatoria Interreg IIIB (Sudoeste). que integra a organizaciones de productores, centros de I+D y formación, organismos públicos de las zonas anteriormente descritas

The growth of the buccal mass in Sepia officinalis: functional changes throughout ontogeny

Due to their small size, juveniles are more likely to show lower absolute levels of performance leading to a potential competitive disadvantage compared to adults. Therefore, juveniles are expected to compensate by showing a higher relative performance, and/or partitioning resources to overcome this performance disadvantage. Here, we investigate the link between ontogeny and feeding performance in the common cuttlefish Sepia officinalis. We explore the changes in beak shape, wear pattern, mechanical properties, muscular anatomy, and bite force during growth from 3-month post hatching to adults. We show that both upper and lower beaks present important ontogenetic shape variation in the rostrum area that might be due to wear induced by feeding. The mechanical properties of the beaks in juveniles indicate greater resistance compared to adults. Tanning observed on the beaks provides reinforcement to areas under high load during biting. In addition, muscle development and relative bite force were found to differ between cuttlefish of different ages, resulting in juveniles having a similar bite force for their size but with a muscular advantage for opening. Finally, an isometric relation is found in the bite force of S. officinalis, with no sign of feeding performance compensation in juveniles. Feeding performance thus does not reflect the ontogenetic shift from a crustacean-based diet in juveniles to a fish-based diet in adults

Effect of sugar and acid composition, aroma release and assessment conditions on aroma enhancement by taste in model wines

Context: When congruent taste and retronasal aroma are perceived simultaneously, aroma can be enhanced by taste. Different explanations have been proposed: (i) physico-chemical interactions between tastants and aroma compounds, inducing a change of the aroma stimulus before it reaches the receptors, (ii) a contextual bias during sensory tests (dumping), when at least one relevant attribute is not proposed to the panelists to assess a product, (iii) a misunderstanding of the conceptual difference between aroma and taste, or (iv) a perceptual incapability of panelists to distinguish between two congruent percepts. This study was undertaken to better understand aroma enhancement by taste in model wines containing different sugar and acid concentrations but the same volatile composition. Method: We used a twofold approach: model wine retronasal aroma intensity was assessed twice by trained panelists. During the first session, panelists only assessed aroma intensity. During the second session, taste intensity was assessed before aroma intensity, to reduce dumping effects. In-mouth release of volatile compounds was measured by nosespace analysis with the same panelists. Results: Acid concentration influenced aroma compounds release, but it did not impact perceived aroma intensity. Increasing sugar concentration delayed ethyl octanoate (EO) release after swallowing. When taste was not assessed, perceived aroma intensity was not explained by aroma compounds release, but it increased with sugar concentration, probably because of a dumping effect. When taste was assessed, aroma intensity also depended on sugar concentration, but it was significantly correlated to the time of release of EO. Our hypothesis is that when taste declined, late aroma was more easily individualized, and thus assessed with a higher intensity. This entails that panelists focused on aroma to individualize it from taste. We concluded that trained panelists understand the conceptual difference between taste and aroma, but are not completely able to distinguish congruent and simultaneous taste and aroma percepts

A physical map of the heterozygous grapevine 'Cabernet Sauvignon' allows mapping candidate genes for disease resistance

<p>Abstract</p> <p>Background</p> <p>Whole-genome physical maps facilitate genome sequencing, sequence assembly, mapping of candidate genes, and the design of targeted genetic markers. An automated protocol was used to construct a <it>Vitis vinifera </it>'Cabernet Sauvignon' physical map. The quality of the result was addressed with regard to the effect of high heterozygosity on the accuracy of contig assembly. Its usefulness for the genome-wide mapping of genes for disease resistance, which is an important trait for grapevine, was then assessed.</p> <p>Results</p> <p>The physical map included 29,727 BAC clones assembled into 1,770 contigs, spanning 715,684 kbp, and corresponding to 1.5-fold the genome size. Map inflation was due to high heterozygosity, which caused either the separation of allelic BACs in two different contigs, or local mis-assembly in contigs containing BACs from the two haplotypes. Genetic markers anchored 395 contigs or 255,476 kbp to chromosomes. The fully automated assembly and anchorage procedures were validated by BAC-by-BAC blast of the end sequences against the grape genome sequence, unveiling 7.3% of chimerical contigs. The distribution across the physical map of candidate genes for non-host and host resistance, and for defence signalling pathways was then studied. NBS-LRR and RLK genes for host resistance were found in 424 contigs, 133 of them (32%) were assigned to chromosomes, on which they are mostly organised in clusters. Non-host and defence signalling genes were found in 99 contigs dispersed without a discernable pattern across the genome.</p> <p>Conclusion</p> <p>Despite some limitations that interfere with the correct assembly of heterozygous clones into contigs, the 'Cabernet Sauvignon' physical map is a useful and reliable intermediary step between a genetic map and the genome sequence. This tool was successfully exploited for a quick mapping of complex families of genes, and it strengthened previous clues of co-localisation of major NBS-LRR clusters and disease resistance <it>loci </it>in grapevine.</p

SAS-6 engineering reveals interdependence between cartwheel and microtubules in determining centriole architecture

Centrioles are critical for the formation of centrosomes, cilia and flagella in eukaryotes. They are thought to assemble around a nine-fold symmetric cartwheel structure established by SAS-6 proteins. Here, we have engineered Chlamydomonas reinhardtii SAS-6-based oligomers with symmetries ranging from five- to ten-fold. Expression of a SAS-6 mutant that forms six-fold symmetric cartwheel structures in vitro resulted in cartwheels and centrioles with eight- or nine-fold symmetries in vivo. In combination with Bld10 mutants that weaken cartwheel-microtubule interactions, this SAS-6 mutant produced six- to eight-fold symmetric cartwheels. Concurrently, the microtubule wall maintained eight- and nine-fold symmetries. Expressing SAS-6 with analogous mutations in human cells resulted in nine-fold symmetric centrioles that exhibited impaired length and organization. Together, our data suggest that the self-assembly properties of SAS-6 instruct cartwheel symmetry, and lead us to propose a model in which the cartwheel and the microtubule wall assemble in an interdependent manner to establish the native architecture of centrioles