Éditeur(s) : HAL CCSD Nature Publishing Group
Résumé : International audience
Evolution involves interplay between natural selection and developmental constraints(1-3). This is seen, for example, when digits are lost from the limbs during evolution(1,3,4). Extant archosaurs (crocodiles and birds) show several instances of digit loss(3,5,6) under different selective regimes, and show limbs with one, two, three, four or the ancestral number of five digits. The `lost' digits sometimes persist for millions of years as developmental vestiges(7-10). Here we examine digit loss in the Nile crocodile and five birds, using markers of three successive stages of digit development. In two independent lineages under different selection, wing digit I and all its markers disappear. In contrast, hindlimb digit V persists in all species sampled, both as cartilage, and as Sox9-expressing precartilage domains, 250 million years after the adult digit disappeared. There is therefore a mismatch between evolution of the embryonic and adult phenotypes. All limbs, regardless of digit number, showed similar expression of sonic hedgehog (Shh). Even in the one-fingered emu wing, expression of posterior genes Hoxd11 and Hoxd12 was conserved, whereas expression of anterior genes Gli3 and Alx4 was not. We suggest that the persistence of digit V in the embryo may reflect constraints, particularly the conserved posterior gene networks associated with the zone of polarizing activity (ZPA(11)). The more rapid and complete disappearance of digit I may reflect its ZPA-independent specification, and hence, weaker developmental constraints. Interacting with these constraints are selection pressures for limb functions such as flying and perching. This model may help to explain the diverse patterns of digit loss in tetrapods. Our study may also help to understand how selection on adults leads to changes in development.
ISSN: 0028-0836

hal-01545485
https://hal.archives-ouvertes.fr/hal-01545485
DOI : 10.1038/nature12336

Éditeur(s) : HAL CCSD Wiley
Résumé : Question: To establish a habitat classification based on functional group co-occurrence that may help the drawing up of conservation plans. Location: Riverine forest fragments in the Grand-duché de Luxembourg, Europe. Methods: Forest fragments were surveyed for their abundance of vascular plants. These were clustered into emergent groups according to 14 life-traits related 10 plant dispersal, establishment and persistence. Forest fragments were classified according to similar distribution of the identified emergent groups. Environmental factors were related to the emergent group richness in each forest type using generalized linear models. Results: Contrary to former species centred classification, only two groups of forests, each with clearly different emergent group composition and conservation requirements. Were detected: (1) swamp forests characterized by anemogamous perennials, annuals and hydrochorous perennials and (2) moist forests characterized by barochorous perennials, small geophytes and zoochorous phanerophytes. From a conservation point of view, priority should he given to large swamp forest with intact flooding regimes his is in accordance with the high wind and water dispersal capacities of their typical emergent groups. For the moist forests. conservation priorities should he high forest connectivity and historical continuity since dispersal and establishment of their characteristic emergent groups arc highly limited. Conclusions: The described methodology, situated at an intermediate integration level between the individual species and whole community descriptors. takes advantage of both conservation plans built for single species and the synthetic power of bread ecological measures.
ISSN: 1402-2001

hal-01031884
https://hal.archives-ouvertes.fr/hal-01031884

Éditeur(s) : HAL CCSD
Résumé : Indigenous territories comprise extensive areas of tropical forest and hold significant social and conservation value. Today, they are subject to various constraints and opportunities, and face many territorial transformations. These transformations are complex and multifaceted. They involve the adoption of new production and consumption modes, the modification of forms of social organisation and identity and territorial claims. However, the links between these on-going processes are still poorly understood, and make difficult to appreciate the adaptation dynamics of indigenous common natural resources management. This thesis is particularly concerned with the territorial dynamics of the Wayãpi and Teko indigenous people of the municipality of Camopi in French Guiana. It integrates methods that include land use analysis using remotely sensed data, socio-economic and agricultural systems analysis at the household scale, and empirical analysis on the influence of identity claims, kinship networks, and conservation policies. It shows that despite the residential settlement around local towns, the growth of cash income from wage labour and welfare, associated with strong kinship networks, allows the revival of mobility and the diversification of indigenous territorialities. Environmental policies implemented on the territory involve processes of identity and territorial claims and motivate the construction of a collective project of endogenous local development. A comparative approach with the situation of the wayãpi people living in Brazil and evolving in a completely different institutional, socio-economic and environmental context shows similar dynamics. Indigenous peoples of these two sites adopt "multi-local" land use systems, allowing them to extend their territory occupation and taking part of a broader dynamic of territorial and identity affirmation. They articulate forest and local town environments. This multi-local land use system can be interpreted as a new form of environmental governance, which overcomes the access difficulties to natural resources around local towns and ensures their sovereignty over the territory.
Les territoires amérindiens couvrent de vastes étendues de forêts tropicales et possèdent une forte valeur sociale et environnementale. Soumis à des contraintes et opportunités variées, ils sont de nos jours le siège de nombreuses transformations territoriales. Ces transformations sont complexes et multiformes. Elles impliquent l'adoption de nouveaux modes de production et de consommation, le réajustement des formes d'organisation sociale et des dynamiques de réaffirmation identitaire et territoriale. Or les liens entre tous ces processus sont encore mal compris, et rendent délicate la compréhension des dynamiques d'adaptation des systèmes amérindiens de gestion des ressources communes. Cette thèse s'intéresse particulièrement aux dynamiques territoriales des Amérindiens wayãpi et teko de la commune de Camopi en Guyane française. Elle intègre des données sur l'occupation du sol obtenues par télédétection, des données socio-économiques et productives à l'échelle des ménages et des données qualitatives sur les processus identitaires, les réseaux de parenté, les politiques de conservation et la gouvernance du territoire. Elle montre que malgré la sédentarisation de l'habitat autour des bourgs locaux, la croissance des revenus monétaires issus des emplois salariés et des aides sociales, combinée avec le maintien de réseaux de parenté et d'entraide, permet une redynamisation des systèmes de mobilité et une diversification des territorialités amérindiennes. De plus, les politiques environnementales mises en place sur le territoire impliquent des processus de territorialisation et de revendications identitaires et motivent la construction collective d'un projet de développement local endogène. Une approche comparative avec la situation des Amérindiens wayãpi vivant au Brésil et évoluant dans un contexte socio-économique, institutionnel et environnemental bien différent montre des dynamiques similaires. Les Amérindiens de ces deux pays adoptent des systèmes d'exploitation du territoire multi-locaux, leur permettant d'étendre leur occupation du territoire et s'inscrivant dans une dynamique de réaffirmation identitaire et territoriale. Ils articulent ainsi les espaces de la forêt et des bourgs. Cette forme d'exploitation multi-locale du territoire peut être interprétée comme une nouvelle forme de gouvernance environnementale, qui leur permet de contourner les difficultés d'accès aux ressources naturelles autour des bourgs et d'affirmer leur souveraineté sur le territoire.
https://tel.archives-ouvertes.fr/tel-00831619

tel-00831619
https://tel.archives-ouvertes.fr/tel-00831619
https://tel.archives-ouvertes.fr/tel-00831619/document
https://tel.archives-ouvertes.fr/tel-00831619/file/These_TRITSCH_mai2013_vf.pdf

Éditeur(s) : HAL CCSD
Résumé : French Guiana is a region located on the Guiana Shield in South America. Is presents at the same time a high originality in biodiversity, a good state of conservation and a strong correlation to Amazonian carbon stocks. Knowledge on evolution of the forest structure of French Guiana is however still insufficient to bring an optimal management at territory scale. Availability as never seen before of remote sensing data at high spatial resolution such as LiDAR, on large coverage, offers the opportunity to assess the forest resource in French Guiana. The work done during this thesis aim mostly to study the structure and the variations of the canopy height, the factors determining its variability and the consequences of forest logging activities. The data used during this thesis come from an airborne LiDAR and field data from Office National des Forêts (ONF). This thesis manuscript is divided in three parts. The first part introduces the problem and sets the objectives of the thesis. The second part takes the so-called "article" form, that is, the different chapters that compose it are scientific articles published or in the course of publication, it is composed of three studies (I) A study on the gaps detection and environmental determinants on the gap sizes distribution in natural forest: How to characterize the gap size distribution and are there environmental determinants that influence the statistical distribution of gap size? This article has been submitted in Biogeoscience. (ii) A study of the control of the environment on the canopy height structure and variations at different spatial resolutions. Which spatial scales are relevant for analyzing the environmental determinants of canopy height changes in tropical forests from remote sensing data? How can the environment help or not map the height of the canopy in the rainforest? This article was accepted for publication in Remote Sensing. (iii) a third study where we quantified the effects of Reduced Impact Logging (RIL) on the structure and variation of canopy height. What are the effects of logging on canopy height variations and gap size distribution? This article will be submitted for publication in a Forest Ecology and Management journal. In the last part, after a synthesis of the main results, we propose a conclusion.
La Guyane française est une région située sur le Plateau des Guyanes en Amérique du sud. Elle présente à la fois une grande originalité en termes de biodiversité, un bon état de conservation et une forte contribution au stock de carbone Amazonien. Les connaissances sur l’évolution de la structure forestière de la Guyane française restent cependant insuffisantes pour offrir une gestion optimale à l’échelle du territoire. La disponibilité sans précédent de données de télédétection à très haute résolution spatiale telles que le LiDAR , sur de larges couvertures nous offre l'opportunité d’évaluer la ressource forestière de la Guyane Française. Les travaux réalisés dans le cadre de cette thèse visent prioritairement à étudier la structure et les variations de la hauteur de canopée, les facteurs déterminant sa variabilité ainsi que les conséquences des activités d’exploitation forestière. Les données utilisées au cours de la thèse proviennent d’un LiDAR aéroporté et des données de terrains de l'Office National des Forêts (ONF). Ce manuscrit de thèse est divisé en trois grandes parties. La première partie introduit la problématique et fixe les objectifs de la thèse. La seconde partie prend la forme dite « sur article », c'est-à-dire que les différents chapitres qui la compose sont des articles scientifiques publiés ou en cours de publication, elle est composée de trois études. (i) Une étude concernant la détection des trouées et des déterminants environnementaux sur la distribution de tailles des trouées en forêt non exploitée : Comment caractériser la distribution de taille des trouées et est-ce qu’il y a des déterminants environnementaux qui influencent la distribution statistique de taille de trouées? Cet article à été soumis dans Biogeoscience. (ii) Une étude du contrôle de l'environnement sur la structure et les variations de la hauteur de canopée à différentes résolutions spatiales. Quelles échelles spatiales sont pertinentes pour analyser les déterminants environnementaux des variations de hauteur de la canopée en forêt tropicale à partir des données de télédétection ? Comment l’environnement peut aider, ou pas, à cartographier la hauteur de la canopée en forêt tropicale ? Cet article à été accepté pour publication dans Remote Sensing. (iii) Une troisième étude où nous avons quantifié les effets de l’exploitation à faible impact (EFI) sur la structure et la variation de la hauteur de canopée. Quelles sont les effets de l’exploitation forestière sur les variations de hauteur de canopée et sur la distribution de taille des trouées ? Cet article sera soumis pour publication dans une revue scientifique (Forest Ecology and Management). Dans la dernière partie, après une synthèse des principaux résultats, nous proposons des pistes de développement.
https://tel.archives-ouvertes.fr/tel-01527553

NNT : 2016YANE0006
tel-01527553
https://tel.archives-ouvertes.fr/tel-01527553
https://tel.archives-ouvertes.fr/tel-01527553/document
https://tel.archives-ouvertes.fr/tel-01527553/file/these-youven-goulamoussene2.pdf

Éditeur(s) : The Service The Service ( Washington )
Résumé : (Bibliography) Bibliography: p. 296.
(Statement of Responsibility) [by Roberto E. Gierbolini], United States Department of Agriculture Soil Conservation Service in cooperation with University of Puerto Rico College of Agricultural Sciences.
Cover title.
English and Spanish.
(Funding) U.S. Department of Agriculture Soil Surveys
Puerto Rico
Mayagüez Region
Puerto Rico
Mayagüez Region

002821913
02820412
ANV0438
76600686

Éditeur(s) : HAL CCSD
Résumé : Due to their phylogenetic position outside from Bilateria, cnidarians and ctenophores are key phyla to understanding the origin and early evolution of molecular mechanisms, cell types, or body plan features at the level of Metazoa. Unlike other non-bilaterian phyla (sponges and placozoans), they possess neurons and muscle cells. The first part of my work relates to the problem of the origin of the metazoan nervous system. Recent studies have suggested a dual origin for nerve cells, with ctenophore neurons having emerged independently from those of cnidarians and bilaterians. This hypothesis relies on phylogenomic analyses supporting ctenophores as sister-group to all other metazoans, and on the purported absence in ctenophores of almost all well-known neuro-transmission systems, including the cholinergic system. Refuting this claim, I present substantial evidence in favour of acetylcholine (Ach) being used in the ctenophore Pleurobrachia pileus as an extra-cellular messenger, including within the nervous system. This conclusion arises from the conjunction of multiple approaches at the molecular scale (orthology analyses, Ach immuno-localisation, gene in situ hybridisation), at the cellular scale (calcium imaging on muscle cells exposed to Ach) and at the organism scale (pharmacological treatments with an Ach analogue and Ach antagonists). In the second part of my thesis, I address the conservation of molecular mechanisms involved in the control of cellular proliferation. Notably, the Hippo pathway is known for its role in bilaterians in the negative control of cellular proliferation. I show that components of this pathway are conserved in Pleurobrachia pileus and in Clytia hemisphaerica and that the nuclear vs. cytoplasmic localisation of the transcriptional co-factor Yorkie is correlated to the extent of proliferation within C. hemisphaerica tissues. Finally, RNAseq differential gene expression analyses along a cellular conveyor belt of the C. hemisphaerica medusa suggests a tendency for conservation of function among a set of genes whose mammalian orthologues have documented roles in the arrest of cellular proliferation.
Les Cnidaires et les Cténaires sont deux embranchements extérieurs aux Bilatériens qui, de par leur position phylogénétique, constituent des modèles d'étude cruciaux pour comprendre l'origine et l'évolution de mécanismes moléculaires ou encore de types cellulaires à grande échelle chez les Métazoaires. Ils sont les deux seuls embranchements non-Bilatériens à posséder des cellules nerveuses ainsi que des cellules musculaires. La première partie de mon travail de thèse s'inscrit dans le contexte de la compréhension de l'origine du système nerveux des Métazoaires. Des études récentes suggèrent une origine double du système nerveux ; ainsi celui des Cténaires aurait été acquis de manière convergente par rapport à celui des Cnidaires et des Bilatériens. Cela repose sur des données récentes de phylogénomique proposant les Cténaires en tant que groupe-frère de tous les autres Métazoaires et sur l'absence supposée chez les Cténaires de quasiment tous les systèmes de neurotransmission connus y compris le système cholinergique. A l'encontre de ces hypothèses, j'ai pu mettre en évidence l'existence d'un système cholinergique chez le Cténaire Pleurobrachia pileus ainsi que son étroite association avec le système nerveux. Cette conclusion repose sur une multiplicité d'approches à l'échelle moléculaire (analyses d'orthologie, immunolocalisation, hybridations in situ), cellulaire (imagerie calcique) et de l'organisme (approche pharmacologique). Dans la seconde partie de ma thèse, j'aborde la question de la conservation des mécanismes moléculaires impliqués dans le contrôle de la prolifération cellulaire à l'échelle des Métazoaires. J'ai pu mettre en évidence la conservation des acteurs.
https://tel.archives-ouvertes.fr/tel-01633223

NNT : 2015PA066629
tel-01633223
https://tel.archives-ouvertes.fr/tel-01633223
https://tel.archives-ouvertes.fr/tel-01633223v2/document
https://tel.archives-ouvertes.fr/tel-01633223/file/2015PA066629.pdf

Éditeur(s) : Conservation International Conservation International ( Belo Horizonte Minas Gerais Brazil, Belo Horizonte Minas Gerais Brazil )
Résumé : (Additional Physical Form) Also issued online.
(Language) English, Portuguese, and Spanish.
(Dates or Sequential Designation) Vol. 1, no. 1 (Mar. 1993)-
(Issuing Body) Issued jointly with Center for Applied Biodiversity Science,
Published in Washington, D.C., Dec. 1999-Apr. 2005 , Arlington, VA, Aug. 2005-
Latest issue consulted: Vol. 13, no. 1 (Apr. 2005).
Brazil
Latin America

28561619
96648813
1413-4705

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
Background: Ameloblastin (AMBN) is a phosphorylated, proline/glutamine-rich protein secreted during enamel formation. Previous studies have revealed that this enamel matrix protein was present early in vertebrate evolution and certainly plays important roles during enamel formation although its precise functions remain unclear. We performed evolutionary analyses of AMBN in order to (i) identify residues and motifs important for the protein function, (ii) predict mutations responsible for genetic diseases, and (iii) understand its molecular evolution in mammals. Results: In silico searches retrieved 56 complete sequences in public databases that were aligned and analyzed computationally. We showed that AMBN is globally evolving under moderate purifying selection in mammals and contains a strong phylogenetic signal. In addition, our analyses revealed codons evolving under significant positive selection. Evidence for positive selection acting on AMBN was observed in catarrhine primates and the aye-aye. We also found that (i) an additional translation initiation site was recruited in the ancestral placental AMBN, (ii) a short exon was duplicated several times in various species including catarrhine primates, and (iii) several polyadenylation sites are present. Conclusions: AMBN possesses many positions, which have been subjected to strong selective pressure for 200 million years. These positions correspond to several cleavage sites and hydroxylated, O-glycosylated, and phosphorylated residues. We predict that these conserved positions would be potentially responsible for enamel disorder if substituted. Some motifs that were previously identified as potentially important functionally were confirmed, and we found two, highly conserved, new motifs, the function of which should be tested in the near future. This study illustrates the power of evolutionary analyses for characterizing the functional constraints acting on proteins with yet uncharacterized structure.
ISSN: 1471-2148

Droits : http://creativecommons.org/licenses/by/
hal-01212816
http://hal.upmc.fr/hal-01212816
http://hal.upmc.fr/hal-01212816/document
http://hal.upmc.fr/hal-01212816/file/s12862-015-0431-0.pdf
DOI : 10.1186/s12862-015-0431-0

Éditeur(s) : HAL CCSD
Résumé :   Diplôme : DEA
il s'agit d'un type de produit dont les métadonnées ne correspondent pas aux métadonnées attendues dans les autres types de produit : DISSERTATION
L'étude de la répartition géographique de la diversité génétique résultant de l'histoire des populations apparaît comme fondamentale pour la conservation des espèces. Ainsi, la mise en évidence des relations phylo-géographiques au court du Quaternaire récent, au sein d'une espèce modèle Vouacapoua americana (Caesalpiniaceae), en Guyane française apporte des informations importantes sur la dynamique des populations naturelles. Dans cette étude les loci trn Q-trn S et trn Sa-trn fM sont utilisés afin de déterminer l'histoire évolutive des populations issues des refuges forestiers tropicaux. Le but principal est l'obtention des séquences après amplification PCR. L'analyse de ces séquences chez cinq populations testées a permis de mettre en évidence leur caractère hypervariable, ainsi que des régions présentant des motifs conservés répétés plusieurs fois. Les constructions phylogéographiques obtenues à partir de celles-ci accentuent la régionalisation des différents chlorotypes, existant en Guyane pour cette espèce, mise en évidence au cours de travaux précédents. Ainsi, les informations apportées par cette approche apparaissent comme complémentaires aux résultats obtenus par d'autres techniques d'analyse moléculaire.
https://hal.archives-ouvertes.fr/hal-01189224

hal-01189224
https://hal.archives-ouvertes.fr/hal-01189224
PRODINRA : 16622

Éditeur(s) : HAL CCSD
Résumé : 16 ref. *Atelier sur l'amenagement et la conservation de l'ecosysteme forestier tropical humide;INRA, Nancy (FRA) Diffusion du document : Atelier sur l'amenagement et la conservation de l'ecosysteme forestier tropical humide;INRA, Nancy (FRA)
absent
https://hal.archives-ouvertes.fr/hal-01190947

hal-01190947
https://hal.archives-ouvertes.fr/hal-01190947
PRODINRA : 96780

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
The influence of conservation policies on environmental governance by indigenous peoples is not well understood. Our goal is to understand the role of conservation policies in the on-going social, spatial and temporal reorganisation of common natural resources management by the Wayãpi and Teko in French Guiana. Using socio-economic and land use variables, we explain their territorial reorganisation. We show how the delimitation of protected areas encourages identity claims and resources re-appropriation, which play a determining role in territorial reorganisation.Finally, we focus on the emergence of a new form of environmental governance based on “multi-sited” land use system.
ISSN: 0261-3050

Droits : info:eu-repo/semantics/OpenAccess
hal-01135244
https://hal.archives-ouvertes.fr/hal-01135244
https://hal.archives-ouvertes.fr/hal-01135244/document
https://hal.archives-ouvertes.fr/hal-01135244/file/Tritsch_al_Toward_revival_indigenous_mobility_Bull.Lat.Am.Research_2015.pdf
DOI : 10.1111/blar.12204

Éditeur(s) : HAL CCSD Réseau « Développement durable et territoires fragiles »
Résumé : La Trame verte et bleue (TVB), nouveau dispositif d'action publique visant à enrayer la perte de biodiversité traduit un renouvellement des référentiels de justification des politiques de conservation et de leur stratégie territoriale. Il s'agit d'intégrer la planification écologique dans l'aménagement de l'ensemble du territoire. Le processus de territorialisation de la TVB met en rapport de multiples niveaux de décision et d'action imbriqués. Il crée de ce fait des configurations inédites de complexité et d'incertitude et implique des innovations en termes de gouvernance que le cadre analytique de la gouvernance adaptative permet d'appréhender. En nous appuyant sur l'exemple du Parc Naturel Régional des Volcans d'Auvergne, nous analysons le rôle que ces institutions sont susceptibles de jouer dans ces dynamiques de changement et d'apprentissage socio-technique et politique qui conditionnent une mise en œuvre effective de la TVB.
Développement Durable et territoires

hal-00979610
https://hal-agroparistech.archives-ouvertes.fr/hal-00979610

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
Dentin matrix acidic phosphoprotein 1 (DMP1) is an acidic, highly phosphorylated, noncollagenous protein secreted during dentin and bone formation. Previous functional studies of DMP1 have revealed various motifs playing a role in either mineralization or cell differentiation. We performed an evolutionary analysis of DMP1 to identify residues and motifs that were conserved during 220 millions years (Ma) of mammalian evolution, and hence have an important function. In silico search provided us with 41 sequences that were aligned and analyzed using the Hyphy program. We showed that DMP1 contains 55 positions that were kept unchanged for 220 Ma. We also defined in a more precise manner some motifs that were already known (i.e., cleavage sites, RGD motif, ASARM peptide, glycosaminoglycan chain attachment site, nuclear localization signal sites, and dentin sialophosphoprotein-binding site), and we found five, highly conserved, new functional motifs. In the near future, functional studies could be performed to understand the role played by them.
ISSN: 0022-2844

hal-01545482
https://hal.archives-ouvertes.fr/hal-01545482
DOI : 10.1007/s00239-013-9539-2

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
Chromatin modification enzymes are important regulators of gene expression and some are evolutionarily conserved from yeast to human. Saccharomyces cerevisiae is a major model organism for genome-wide studies that aim at the identification of target genes under the control of conserved epigenetic regulators. Ume6 interacts with the upstream repressor site 1 (URS1) and represses transcription by recruiting both the conserved histone deacetylase Rpd3 (through the co-repressor Sin3) and the chromatin-remodeling factor Isw2. Cells lacking Ume6 are defective in growth, stress response, and meiotic development. RNA profiling studies and in vivo protein-DNA binding assays identified mRNAs or transcript isoforms that are directly repressed by Ume6 in mitosis. However, a comprehensive understanding of the transcriptional alterations, which underlie the complex ume6Δ mutant phenotype during fermentation, respiration, or sporulation, is lacking. We report the protein-coding transcriptome of a diploid MAT a/α wild-type and ume6/ume6 mutant strains cultured in rich media with glucose or acetate as a carbon source, or sporulation-inducing medium. We distinguished direct from indirect effects on mRNA levels by combining GeneChip data with URS1 motif predictions and published high-throughput in vivo Ume6-DNA binding data. To gain insight into the molecular interactions between successive waves of Ume6-dependent meiotic genes, we integrated expression data with information on protein networks. Our work identifies novel Ume6 repressed genes during growth and development and reveals a strong effect of the carbon source on the derepression pattern of transcripts in growing and developmentally arrested ume6/ume6 mutant cells. Since yeast is a useful model organism for chromatin-mediated effects on gene expression, our results provide a rich source for further genetic and molecular biological work on the regulation of cell growth and cell differentiation in eukaryotes.
ISSN: 1617-4615

hal-01151619
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01151619
DOI : 10.1007/s00438-015-1051-5
PUBMED : 25957495

Éditeur(s) : Conservation International Conservation International ( Belo Horizonte Minas Gerais Brazil, Belo Horizonte Minas Gerais Brazil )
Résumé : (Additional Physical Form) Also issued online.
(Language) English, Portuguese, and Spanish.
(Dates or Sequential Designation) Vol. 1, no. 1 (Mar. 1993)-
(Issuing Body) Issued jointly with Center for Applied Biodiversity Science,
Published in Washington, D.C., Dec. 1999-Apr. 2005 , Arlington, VA, Aug. 2005-
Latest issue consulted: Vol. 13, no. 1 (Apr. 2005).
Brazil
Latin America

28561619
96648813
1413-4705

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
The Western Indian Ocean harbors one of theworld’s most diverse marine biota yet is threatened byexploitation with few conservation measures in place.Primary candidates for conservation in the region are theScattered Islands (Iles Eparses), a group of relativelypristine and uninhabited islands in the MozambiqueChannel. However, while optimal conservation strategiesdepend on the degree of population connectivity amongspatially isolated habitats, very few studies have beenconducted in the area. Here, we use highly variablemicrosatellite markers from two damselfishes (Amphiprionakallopisos and Dascyllus trimaculatus) with differing lifehistory traits [pelagic larval duration (PLD), adult habitat]to compare genetic structure and connectivity among theseislands using classic population structure indices as well asBayesian clustering methods. All classical fixation indexesFST, RST, G0ST, and Jost’s D show stronger genetic differentiationamong islands for A. akallopisos compared to D.trimaculatus, consistent with the former species’ shorterPLD and stronger adult site attachment, which may restrictlarval dispersal potential. In agreement with these results,the Bayesian analysis revealed clear genetic differentiationamong the islands in A. akallopisos, separating the southerngroup (Bassas da India and Europa) from the center(Juan de Nova) and northern (Iles Glorieuses) islands, butnot for D. trimaculatus. Local oceanographic patterns suchas eddies that occur along the Mozambique Channel appearto parallel the results reported for A. akallopisos, but suchfeatures seem to have little effect on the genetic differentiationof D. trimaculatus. The contrasting patterns ofgenetic differentiation between species within the samefamily highlight the importance of accounting for diverselife history traits when assessing community-wide connectivity,an increasingly common consideration in conservationplanning.
ISSN: 0722-4028

hal-01561992
https://hal-univ-perp.archives-ouvertes.fr/hal-01561992
DOI : 10.1007/s00338-016-1495-z

Éditeur(s) : HAL CCSD MDPI
Résumé : International audience
The future of tropical managed forests is threatened by climate change. In anticipation of the increase in the frequency of drought episodes predicted by climatic models for intertropical regions, it is essential to study commercial trees' resilience and vulnerability to water stress by identifying potential interaction effects between selective logging and stress due to a lack of water. Focusing on 14 species representing a potential or acknowledged commercial interest for wood production in the Guiana Shield, a joint model coupling growth and mortality for each species was parametrized, including a climatic variable related to water stress and the quantity of aboveground biomass lost after logging. For the vast majority of the species, water stress had a negative impact on growth rate, while the impact of logging was positive. The opposite results were observed for the mortality. Combining results from growth and mortality models, we generate vulnerability profiles and ranking from species apparently quite resistant to water stress (Chrysophyllum spp., Goupia glabra Aubl., Qualea rosea Aubl.), even under logging pressure, to highly vulnerable species (Sterculia spp.). In light of our results, forest managers in the Guiana Shield may want to conduct (i) a conservation strategy of the most vulnerable species and (ii) a diversification of the logged species. Conservation of the already-adapted species may also be considered as the most certain way to protect the tropical forests under future climates.
ISSN: 1999-4907

hal-01315432
https://hal-sde.archives-ouvertes.fr/hal-01315432
DOI : 10.3390/f7050105

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
DNase I requires Ca²+ and Mg²+ for hydrolyzing double-stranded DNA. However, the number and the location of DNase I ion-binding sites remain unclear, as well as the role of these counter-ions. Using molecular dynamics simulations, we show that bovine pancreatic (bp) DNase I contains four ion-binding pockets. Two of them strongly bind Ca²+ while the other two sites coordinate Mg²+. These theoretical results are strongly supported by revisiting crystallographic structures that contain bpDNase I. One Ca²+ stabilizes the functional DNase I structure. The presence of Mg²+ in close vicinity to the catalytic pocket of bpDNase I reinforces the idea of a cation-assisted hydrolytic mechanism. Importantly, Poisson-Boltzmann-type electrostatic potential calculations demonstrate that the divalent cations collectively control the electrostatic fit between bpDNase I and DNA. These results improve our understanding of the essential role of cations in the biological function of bpDNase I. The high degree of conservation of the amino acids involved in the identified cation-binding sites across DNase I and DNase I-like proteins from various species suggests that our findings generally apply to all DNase I-DNA interactions.
ISSN: 1553-734X

hal-00645165
https://hal.archives-ouvertes.fr/hal-00645165
https://hal.archives-ouvertes.fr/hal-00645165/document
https://hal.archives-ouvertes.fr/hal-00645165/file/journal.pcbi.1001000.pdf
DOI : 10.1371/journal.pcbi.1001000

Éditeur(s) : HAL CCSD Pacific-credo Publications
Résumé : International audience
Les sciences humaines et sociales dans le Pacifique Sud, terrain questions et méthodes

ISBN : 978-2-9537485-2-9
hal-01342961
https://hal-univ-perp.archives-ouvertes.fr/hal-01342961

Éditeur(s) : HAL CCSD SAGE Publications (UK and US)
Résumé : International audience
Molecular evolutionary analysis is an efficient method to predict and/or validate amino acid substitutions that could lead to a genetic disease and to highlight residues and motifs that could play an important role in the protein structure and/or function. We have applied such analysis to amelotin (AMTN), a recently identified enamel protein in the rat, mouse, and humans. An in silico search for AMTN provided 42 new mammalian sequences that were added to the 3 published sequences with which we performed the analysis using a dataset representative of all lineages (circa 220 million years of evolution), including 2 enamel-less species, sloth and armadillo. During evolution, of the 209 residues of human AMTN, 17 were unchanged and 34 had conserved their chemical properties. Substituting these important residues could lead to amelogenesis imperfecta (AI). Also, AMTN possesses a well-conserved signal peptide, 2 conserved motifs whose function is certainly important but unknown, and a putative phosphorylation site (SXE). In addition, the sequences of the 2 enamel-less species display mutations revealing that AMTN underwent pseudogenization, which suggests that AMTN is an enamel-specific protein.
ISSN: 0022-0345

hal-01545488
https://hal.archives-ouvertes.fr/hal-01545488
DOI : 10.1177/0022034512460551