Éditeur(s) : HAL CCSD
Résumé : International audience
In two swordtail species of the genus Xiphophorus, the onset of puberty has been shown to be modulated at the P locus by sequence polymorphism and gene copy-number variation affecting the type 4 melanocortin hormone receptor Mc4r. The system works through the interaction of two allelic types, one encoding wild type and the other dominant-negative receptors. We have analyzed the structure and evolution of the P locus in the platyfish Xiphophorus maculatus, where as many as nine alleles of P determining the onset of sexual maturity in males and females, fecundity in females, and adult size in males are located on both the X and Y chromosomes in a region linked to the master sex-determining locus. In this species, mc4r has been amplified to up to 10 copies on both the X and Y chromosomes through recent large serial duplications. Subsequently, mc4r paralogues have diverged considerably into many different subtypes. Certain copies have acquired new untranslated regions through genomic rearrangements, and transposable element insertions and other mutations have accumulated in promoter regions, possibly explaining observed deviations from the classical mc4r transcriptional pattern. In the mc4r-coding sequence, in-frame insertions and deletions as well as nonsense and missense mutations have generated a high diversity of Mc4r-predicted proteins. Most of these variants are expressed in embryos, adults, and/or tumors. Functional receptor characterization demonstrated major divergence in pharmacological behavior for Mc4r receptors encoded by different copies of platyfish mc4r, with differences in constitutive activity as well as binding and stimulation by hormones. The high degree of allelic and copy-number variation observed between individuals can explain the high level of polymorphism for sexual maturation, fecundity, and body size in the platyfish: multiple combinations of Mc4r variants with different biochemical properties might interact to modulate the melanocortin signaling that regulates the hypothalamus-pituitary-gonadal axis.
GENETICS

hal-01544912
https://hal.archives-ouvertes.fr/hal-01544912
DOI : 10.1534/genetics.113.155952

Éditeur(s) : HAL CCSD Mineralogical Society of America
Résumé : International audience
Wadsleyites with various iron contents were synthesized at ~12-14 GPa and 1400 °C under oxidizing and hydrous conditions in coexistence with enstatite. The samples were studied using micro-X-ray absorption near edge structure (XANES) and micro-Mössbauer spectroscopy to determine the ferric iron contents in polyphasic samples and secondary ion mass spectrometry (SIMS) to determine the water concentrations. XANES and Mössbauer analyses show that ferric iron content increases with increasing total iron content, and reaches a maximum of ~30% Fe3+/Fetotal. Two XANES results were cross-checked by Mössbauer analysis and both methods are in reasonable agreement. The use of Fourier transform infrared spectroscopy reveals a new protonation scheme in wadsleyite, with a significant proportion of protons associated with the high-frequency band at 3611 cm−1 and a new band located at 3500 cm−1. The intensity of these two bands is higher for Fe3+-rich wadsleyite. SIMS analyses show that water contents in wadsleyite vary from 4500 to 9400 ppm H2O by weight. Pyroxene water contents range from 790 to 1600 ppm wt H2O. The concentration of water in both phases decreases with increasing iron content. The partition coefficient of water between wadsleyite and pyroxene varies between 5 and 9 and increases with increasing Fe-number of wadsleyite [i.e., XFe/(XFe + XMg) × 100 ratio]. The divalent cation concentrations (i.e., Mg2+ + Fe2+), the Si as well as the H content in wadsleyite decrease with increasing Fe3+ content, indicating an incorporation mechanism via substitution into the metal (Me = Mg2+ and Fe2+) and Si sites with a ratio of 5/3 for (Fe3++H+):Me and of 5/1 for (Fe3++H+):Si, similarly as in the dry system. Thus, coupled substitution of Fe3+ and H+ does not affect the incorporation mechanism of Fe3+, but does affect the location of H+, which is partly incorporated at tetrahedral edges forming [FeSi′-(OH)o*]X neutral defects substituting for Si. In this model 25% of the ferric iron occupies the tetrahedral sites.
ISSN: 0003-004X

hal-00758071
https://hal.archives-ouvertes.fr/hal-00758071
DOI : 10.2138/am.2012.3869

Éditeur(s) : Monachii ; Lipsiae : apud R. Oldenbourg in comm.
Extrait de : Flora brasiliensis : enumeratio plantarum in Brasilia hactenus detectarum quas suis aliorumque botanicorum studiis descriptas et methodo naturali digestas partim icone illustratas
Résumé : Édition : 1840-1906
Siècle(s) traité(s) : 19
Droits : Domaine public
Provenance : Université Toulouse III - Paul Sabatier. Service Commun de la Documentation
Permalien : http://www.manioc.org/patrimon/TLS17055
TLS17055

Éditeur(s) : HAL CCSD Météo et Climat
Résumé : International audience
The Convective and Orographically- induced Precipitation Study (COPS) is a coordinated international project, comprised of an observational field campaign and a research programme aiming to advance the quality of fore- casts of orographically-induced pre- cipitation by four-dimensional obser- vations and modelling of its life cycle. The COPS field campaign took place during June-July-August 2007 over eastern France and south-western Germany. Its main objective was to provide an unprecedented comprehen- sive set of in situ and remotely-sensed meteorological observations of the entire depth of the troposphere. After a short overview of the project, the paper focuses on the French contribution to the COPS field phase, describes the experimental setup and highlights some key observations.
L’étude des précipitations convectives induites par l’orographie (Cops selon l’acronyme anglais) est un projet inter- national coordonné qui comprend une campagne d’observations de terrain et un programme scientifique et qui vise à améliorer la qualité des prévisions des précipitations orographiques convectives à la fois par l’observation quadridimensionnelle et la modélisa- tion de leur cycle de vie. La campagne de terrain s’est déroulée en juin-juillet- août 2007 sur l’est de la France et le sud-ouest de l’Allemagne. Son objectif majeur était de fournir un jeu d’obser- vations météorologiques, in situ et à distance, aussi complet que possible et sur toute la profondeur de la colonne troposphérique.Après une brève revue d’ensemble du projet, l’article se concentre sur la contribution française à la campagne Cops, décrit le dispositif expérimental mis en œuvre et met en valeur quelques observations clés.
ISSN: 0026-1181

insu-01504075
https://hal-insu.archives-ouvertes.fr/insu-01504075
https://hal-insu.archives-ouvertes.fr/insu-01504075/document
https://hal-insu.archives-ouvertes.fr/insu-01504075/file/meteo_2009_64_32.pdf
DOI : 10.4267/2042/23632

Éditeur(s) : HAL CCSD
Résumé : National audience
New experimental data on electrical and anelastic properties of oceanic rocks at high pressures and temperatures are compared with the field data of seismic and electrical anomalies observed at oceanic spreading centers. The laboratory results of electrical conductivity and internal friction on gabbro and peridotites permit to estimate a degree of partial melting and maximum temperature in axial magma chambers (12-15% of melting at 1155-1165°C) and at the upper boundary of a source zone at the depth of 40-90 km (less than 5% of melting in the absence of pyroxene crystals and up to 11-14% in the pyroxene reach rocks at 1360-1370°C) at mid-oceanic ridges.
ISSN: 0934-6554

hal-01322920
http://hal.univ-reunion.fr/hal-01322920

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : The diversity and functional identity of organisms are known to be relevant to the maintenance of ecosystem processes but can be variable in different environments. Particularly, it is uncertain whether ecosystem processes are driven by complementary effects or by dominant groups of species. We investigated how community structure (i.e., the diversity and relative abundance of biological entities) explains the community-level contribution of Neotropical ant communities to different ecosystem processes in different environments. Ants were attracted with food resources representing six ant-mediated ecosystem processes in four environments: ground and vegetation strata in cropland and forest habitats. The exploitation frequencies of the baits were used to calculate the taxonomic and trophic structures of ant communities and their contribution to ecosystem processes considered individually or in combination (i.e., multifunctionality). We then investigated whether community structure variables could predict ecosystem processes and whether such relationships were affected by the environment. We found that forests presented a greater biodiversity and trophic complementarity and lower dominance than croplands, but this did not affect ecosystem processes. In contrast, trophic complementarity was greater on the ground than on vegetation and was followed by greater resource exploitation levels. Although ant participation in ecosystem processes can be predicted by means of trophic-based indices, we found that variations in community structure and performance in ecosystem processes were best explained by environment. We conclude that determining the extent to which the dominance and complementarity of communities affect ecosystem processes in different environments requires a better understanding of resource availability to different species.
ISSN: 0029-8549

hal-01606497
https://hal.archives-ouvertes.fr/hal-01606497
DOI : 10.1007/s00442-016-3741-z
PRODINRA : 407457

Éditeur(s) : HAL CCSD Wiley-VCH Verlag
Résumé : International audience
Deciphering the assembly history of the Milky Way is a formidable task, which becomes possible only if one can produce high-resolution chrono-chemo-kinematical maps of the Galaxy. Data from large-scale astrometric and spectroscopic surveys will soon provide us with a well-defined view of the current chemo-kinematical structure of the Milky Way, but will only enable a blurred view on the temporal sequence that led to the present-day Galaxy. As demonstrated by the (ongoing) exploitation of data from the pioneering photometric missions CoRoT, Kepler, and K2, asteroseismology provides the way forward: solar-like oscillating giants are excellent evolutionary clocks thanks to the availability of seismic constraints on their mass and to the tight age-initial-mass relation they adhere to. In this paper we identify five key outstanding questions relating to the formation and evolution of the Milky Way that will need precise and accurate ages for large samples of stars to be addressed, and we identify the requirements in terms of number of targets and the precision on the stellar properties that are needed to tackle such questions. By quantifying the asteroseismic yields expected from PLATO for red-giant stars, we demonstrate that these requirements are within the capabilities of the current instrument design, provided that observations are sufficiently long to identify the evolutionary state and allow robust and precise determination of acoustic-mode frequencies. This will allow us to harvest data of sufficient quality to reach a 10% precision in age. This is a fundamental pre-requisite to then reach the more ambitious goal of a similar level of accuracy, which will only be possible if we have to hand a careful appraisal of systematic uncertainties on age deriving from our limited understanding of stellar physics, a goal which conveniently falls within the main aims of PLATO's core science.
ISSN: 0004-6337

hal-01541393
https://hal.archives-ouvertes.fr/hal-01541393
ARXIV : 1706.3778
BIBCODE : 2017AN....338..644M
DOI : 10.1002/asna.201713385

Éditeur(s) : HAL CCSD Landes Bioscience
Résumé : International audience
In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
Autophagy

hal-00735751
https://hal.archives-ouvertes.fr/hal-00735751
PUBMED : 22966490

Éditeur(s) : Paris : Desenne, Petit, Le Normand

Provenance : Archives départementales de Guadeloupe
Permalien : http://www.manioc.org/patrimon/ADG18181
ADG18181

Éditeur(s) : Paris : A. Savine
Résumé : 2e ed.
Siècle(s) traité(s) : 18
Droits : Domaine public
Provenance : Collectivité territoriale de Martinique. Bibliothèque Schoelcher
Permalien : http://www.manioc.org/patrimon/SCH13062
SCH13062

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
Deciphering the evolutionary processes driving nucleotide variation in multiallelic genes is limited by the number of genetic systems in which such genes occur. The complementary sex determiner (csd) gene in the honey bee Apis mellifera is an informative example for studying allelic diversity and the underlying evolutionary forces in a well-described model of balancing selection. Acting as the primary signal of sex determination, diploid individuals heterozygous for csd develop into females, whereas csd homozygotes are diploid males that have zero fitness. Examining 77 of the functional heterozygous csd allele pairs, we established a combinatorical criteria that provide insights into the minimum number of amino acid differences among those pairs. Given a data set of 244 csd sequences, we show that the total number of csd alleles found in A. mellifera ranges from 53 (locally) to 87 (worldwide), which is much higher than was previously reported (20). Using a coupon-collector model, we extrapolate the presence of in total 116-145 csd alleles worldwide. The hypervariable region (HVR) is of particular importance in determining csd allele specificity, and we provide for this region evidence of high evolutionary rate for length differences exceeding those of microsatellites. The proportion of amino acids driven by positive selection and the rate of nonsynonymous substitutions in the HVR-flanking regions reach values close to 1 but differ with respect to the HVR length. Using a model of csd coalescence, we identified the high originating rate of csd specificities as a major evolutionary force, leading to an origin of a novel csd allele every 400,000 years. The csd polymorphism frequencies in natural populations indicate an excess of new mutations, whereas signs of ancestral transspecies polymorphism can still be detected. This study provides a comprehensive view of the enormous diversity and the evolutionary forces shaping a multiallelic gene.
ISSN: 0737-4038

hal-01544758
https://hal.archives-ouvertes.fr/hal-01544758
DOI : 10.1093/molbev/mst207

Éditeur(s) : Paris : Recueil Sirey
Résumé : 6e édition, entièrement revue et condensée par Maurice Besson. Introduction générale par René Maunier.
Siècle(s) traité(s) : 16
Droits : Domaine public
Provenance : Communauté d'agglomération de La Rochelle. Médiathèque Michel-Crépeau
Permalien : http://www.manioc.org/patrimon/MMC16029
MMC16029

Éditeur(s) : Bordeaux : Pellier-Lawalle

Provenance : Ville de Bordeaux. Bibliothèque municipale
Permalien : http://www.manioc.org/patrimon/BBX19090
BBX19090

Éditeur(s) : Paris : Morizot
Résumé : Nouvelle édition
Description : Nouvelle édition continuée jusqu'à nos jours, d'après les documents scientifiques les plus récents, les derniers voyages et les dernières découvertes par V.-A. Malte-Brun fils,...

Droits : Domaine public
Provenance : Collectivité territoriale de Guyane. Bibliothèque Alexandre-Franconie
Permalien : http://www.manioc.org/patrimon/FRA11197
FRA11197

Ouvrir le document en plein texte

Éditeur(s) : Paris : Société d'éditions géographiques, maritimes et coloniales
Siècle(s) traité(s) : 19
Droits : Domaine public
Provenance : Collectivité territoriale de Guyane. Bibliothèque Alexandre-Franconie
Permalien : http://www.manioc.org/patrimon/FRA12007
FRA12007

Éditeur(s) : Paris : Desenne, Petit, Le Normand

Provenance : Archives départementales de Guadeloupe
Permalien : http://www.manioc.org/patrimon/ADG18128
ADG18128

Éditeur(s) : Paris : A. Challamel
Extrait de : Commission consultative coloniale
Siècle(s) traité(s) : 20
Droits : Domaine public
Provenance : Collectivité territoriale de Guyane. Bibliothèque Alexandre-Franconie
Permalien : http://www.manioc.org/patrimon/FRA12340
FRA12340

Éditeur(s) : Paris : Librairie Hachette et Cie
Siècle(s) traité(s) : 19
Provenance : Archives départementales de Guadeloupe
Permalien : http://www.manioc.org/patrimon/ADG18175
ADG18175

Éditeur(s) : Paris : Librairie Larousse
Siècle(s) traité(s) : 19
Droits : Domaine public
Provenance : Communauté d'agglomération de La Rochelle. Médiathèque Michel-Crépeau
Permalien : http://www.manioc.org/patrimon/MMC16023-2
MMC16023-2

Éditeur(s) : Paris : Morizot
Résumé : Nouvelle édition
Description : Nouvelle édition continuée jusqu'à nos jours, d'après les documents scientifiques les plus récents, les derniers voyages et les dernières découvertes par V.-A. Malte-Brun fils,....
Siècle(s) traité(s) : 19
Droits : Domaine public
Provenance : Collectivité territoriale de Guyane. Bibliothèque Alexandre-Franconie
Permalien : http://www.manioc.org/patrimon/FRA11194
FRA11194