Pratiques agricoles et propriétés agro-écologiques des prairies dans un processus d’intensification écologique : le cas de l’élevage bovin dans le Vercors

National audienceL'élevage bovin pour la production laitière est la composante agricole majeure sur le territoire des Quatre Montagnes dans le massif du Vercors. Sur ce territoire, un enjeu fort soulevé par une grande partie des agriculteurs concerne la question de l'autonomie fourragère. Cet aspect de la production est d'autant plus central qu'il est fortement dépendant des caractéristiques des prairies qui permettent d'assurer la production de fourrage en dépit d'aléas de plus en plus contraignants (sécheresses, dégâts de campagnols…). Comprendre comment maintenir un niveau de production suffisant en s'appuyant sur les propriétés écosystémiques des prairies relève du contexte de l'intensification écologique en abordant les relations entre l'organisation des systèmes d'élevage (usages à l'échelle des parcelles, diversité des types de parcelles au sein des exploitations, distribution au sein du paysage) et les valeurs d'usage et services écosystémiques fournis par les prairies. Au sein du projet multi-sites ANR-SYSTERRA MOUVE (Les interactions Elevage et Territoire dans la mise en mouvement de l’intensification écologique), le territoire des Quatre Montagnes constitue l'un des terrains d'approfondissement pour analyser comment l'évolution des pratiques dans le sens de l'intensification écologique peut permettre d'augmenter le niveau des services écologiques et d'améliorer les capacités d'adaptation des élevages. En nous appuyant sur une typologie préétablie des prairies, basée le type d'usage (fauche, pâturage) et la composition simplifiée de la végétation nous avons mesuré un large panel de propriétés écosystémiques sur un échantillon de 50 parcelles représentant la diversité des types d'usage sur le territoire. Les propriétés mesurée couvrent notamment la structure spécifique (diversité, hétérogénéité) et fonctionnelle des communautés (traits foliaires, structuraux, phénologiques), les caractéristiques agronomiques (teneur en N, C, P…) et écologique (biomasse et diversité microbienne) du sol et du fourrage (production, qualité), autant de proxys pour les grands types de services reconnus : (i) services intrants, (ii) services de production fourragère et (iii) services en lien avec la valeur écologique des prairies. Les premiers résultats révèlent le rôle prépondérant de deux facteurs liés aux usages pour les propriétés agro-écologiques des prairies : la date de première fauche ou pâturage et le caractère temporaire ou permanent des prairies (date du dernier retournement). Les prairies temporaires offrent un bon niveau de services intrant (fertilité, matière organique) et de production et qualité fourragère mais une faible valeur écologique (faible diversité). Cette distinction sur la base des propriétés agro-écologiques est d'autant plus intéressante que les entretiens auprès des éleveurs ont souligné l'importance de la place des prairies temporaires comme une des clés pour l'autonomie fourragère. Ces prairies productives étant également les plus sensibles aux aléas et offrant une moindre souplesse d'utilisation. A terme, notre objectif est d'identifier les compromis, synergies et antagonismes entre les différents types de services rendus (agronomiques, écologiques) en fonction de différents scénarios d'intensification écologique à l'échelle du territoire

esyN: network building, sharing and publishing.

The construction and analysis of networks is increasingly widespread in biological research. We have developed esyN ("easy networks") as a free and open source tool to facilitate the exchange of biological network models between researchers. esyN acts as a searchable database of user-created networks from any field. We have developed a simple companion web tool that enables users to view and edit networks using data from publicly available databases. Both normal interaction networks (graphs) and Petri nets can be created. In addition to its basic tools, esyN contains a number of logical templates that can be used to create models more easily. The ability to use previously published models as building blocks makes esyN a powerful tool for the construction of models and network graphs. Users are able to save their own projects online and share them either publicly or with a list of collaborators. The latter can be given the ability to edit the network themselves, allowing online collaboration on network construction. esyN is designed to facilitate unrestricted exchange of this increasingly important type of biological information. Ultimately, the aim of esyN is to bring the advantages of Open Source software development to the construction of biological networks.This is the final published version of the paper. It's also available from PLOS at http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0106035

Development of the interatrial wall during the ontogenesis of foetuses and children up to one year of age

Background: The foramen ovale, present in foetal interatrial septum, plays an important role during foetal life. During delivery, foramen ovale closes and becomes fossa ovalis, starting the pulmonary circulation. The aim of our study was to describe the growth of the interatrial wall and changes in location of the foramen ovale, and fossa ovalis during the ontogenesis in the human hearts.Materials and methods: The study was performed on post-mortem material obtained from 92 human hearts from 22nd week of foetal life up to 1 year of age, fixed in a 4% formalin solution.Results: The interatrial wall size in the studied development period was greater in the horizontal than in the vertical dimension. During ontogenesis up to 1 year old, the anterior and inferior parts of the interatrial wall increased their shares considerably by 8% and 6%, respectively. The percentage participation of foramen ovale in the interatrial wall construction in the foetal period formed more than 50% of its size and fairly decreased reaching in infants about 39%.Conclusions: Our study demonstrated that during ontogenesis, from the foetal period to infancy, the parts of the interatrial wall increase their dimensions unevenly. The foramen ovale growth is smaller, compared to the rest of the interatrial wall development. On the basis of our data we can assume that the foramen ovale centre tends to be found in the postero-inferior quadrant of the interatrial wall (foetuses) and in postero-superior quadrant of the interatrial wall — in infants

Multiple functionally divergent and conserved copies of alpha tubulin in bdelloid rotifers.

BACKGROUND: Bdelloid rotifers are microscopic animals that have apparently survived without sex for millions of years and are able to survive desiccation at all life stages through a process called anhydrobiosis. Both of these characteristics are believed to have played a role in shaping several unusual features of bdelloid genomes discovered in recent years. Studies into the impact of asexuality and anhydrobiosis on bdelloid genomes have focused on understanding gene copy number. Here we investigate copy number and sequence divergence in alpha tubulin. Alpha tubulin is conserved and normally present in low copy numbers in animals, but multiplication of alpha tubulin copies has occurred in animals adapted to extreme environments, such as cold-adapted Antarctic fish. Using cloning and sequencing we compared alpha tubulin copy variation in four species of bdelloid rotifers and four species of monogonont rotifers, which are facultatively sexual and cannot survive desiccation as adults. Results were verified using transcriptome data from one bdelloid species, Adineta ricciae. RESULTS: In common with the typical pattern for animals, monogonont rotifers contain either one or two copies of alpha tubulin, but bdelloid species contain between 11 and 13 different copies, distributed across five classes. Approximately half of the copies form a highly conserved group that vary by only 1.1% amino acid pairwise divergence with each other and with the monogonont copies. The other copies have divergent amino acid sequences that evolved significantly faster between classes than within them, relative to synonymous changes, and vary in predicted biochemical properties. Copies of each class were expressed under the laboratory conditions used to construct the transcriptome. CONCLUSIONS: Our findings are consistent with recent evidence that bdelloids are degenerate tetraploids and that functional divergence of ancestral copies of genes has occurred, but show how further duplication events in the ancestor of bdelloids led to proliferation in both conserved and functionally divergent copies of this gene.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are

Comparative genomics of bdelloid rotifers: Insights from desiccating and nondesiccating species.

Bdelloid rotifers are a class of microscopic invertebrates that have existed for millions of years apparently without sex or meiosis. They inhabit a variety of temporary and permanent freshwater habitats globally, and many species are remarkably tolerant of desiccation. Bdelloids offer an opportunity to better understand the evolution of sex and recombination, but previous work has emphasised desiccation as the cause of several unusual genomic features in this group. Here, we present high-quality whole-genome sequences of 3 bdelloid species: Rotaria macrura and R. magnacalcarata, which are both desiccation intolerant, and Adineta ricciae, which is desiccation tolerant. In combination with the published assembly of A. vaga, which is also desiccation tolerant, we apply a comparative genomics approach to evaluate the potential effects of desiccation tolerance and asexuality on genome evolution in bdelloids. We find that ancestral tetraploidy is conserved among all 4 bdelloid species, but homologous divergence in obligately aquatic Rotaria genomes is unexpectedly low. This finding is contrary to current models regarding the role of desiccation in shaping bdelloid genomes. In addition, we find that homologous regions in A. ricciae are largely collinear and do not form palindromic repeats as observed in the published A. vaga assembly. Consequently, several features interpreted as genomic evidence for long-term ameiotic evolution are not general to all bdelloid species, even within the same genus. Finally, we substantiate previous findings of high levels of horizontally transferred nonmetazoan genes in both desiccating and nondesiccating bdelloid species and show that this unusual feature is not shared by other animal phyla, even those with desiccation-tolerant representatives. These comparisons call into question the proposed role of desiccation in mediating horizontal genetic transfer

Arterial hypertension and remodeling of the right ventricle

Background: In case of long-term and physiological loads (e.g. during pregnancy or regular athletics training), reversible morphological changes occur in the heart - cardiomyocytes undergo hypertrophy, however, this is not accompanied by impairment of left ventricular function or myocyte metabolism. However, in the course of various pathological processes, as time goes by, gradually permanent morphological changes occur. These changes are referred to as remodeling of the heart muscle, which, regardless of the primary cause, can lead to the development of chronic heart failure. Materials and methods: The study was performed on post-mortem material of 35 human hearts obtained from forensic sections and anatomopathological sections of people who died of non-cardiac causes (mainly traffic accidents, suicide attempts, strokes, acute infections); material was fixed in a 4% formalin solution. The hearts were subjected to macro- and microscopic assessment. During microscopic assessment the features of remodeling were evaluated. Results and conclusions: In vivo and echocardiographic tests, as well as macroscopic evaluation of post-mortem material, suggest the presence of some kind of right ventricular muscle remodeling, however classic microscopic observations, presented in this study do not provide such unambiguous evidence. Thus, the question arises: why and how the right ventricular function is disturbed, sometimes at early stages of arterial hypertension

Multiplicity and Pseudorapidity Distributions of Charged Particles and Photons at Forward Pseudorapidity in Au + Au Collisions at sqrt{s_NN} = 62.4 GeV

We present the centrality dependent measurement of multiplicity and pseudorapidity distributions of charged particles and photons in Au + Au collisions at sqrt{s_NN} = 62.4 GeV. The charged particles and photons are measured in the pseudorapidity region 2.9 < eta < 3.9 and 2.3 < eta < 3.7, respectively. We have studied the scaling of particle production with the number of participating nucleons and the number of binary collisions. The photon and charged particle production in the measured pseudorapidity range has been shown to be consistent with energy independent limiting fragmentation behavior. The photons are observed to follow a centrality independent limiting fragmentation behavior while for the charged particles it is centrality dependent. We have carried out a comparative study of the pseudorapidity distributions of positively charged hadrons, negatively charged hadrons, photons, pions, net protons in nucleus--nucleus collisions and pseudorapidity distributions from p+p collisions. From these comparisons we conclude that baryons in the inclusive charged particle distribution are responsible for the observed centrality dependence of limiting fragmentation. The mesons are found to follow an energy independent behavior of limiting fragmentation while the behavior of baryons seems to be energy dependent.Comment: 17 pages and 20 figure