Éditeur(s) : HAL CCSD
Résumé : Enamel formation requires the involvement of secretory calcium-binding phosphoproteins. Three of them, amelogenin (AMEL), ameloblastin (AMBN) and enamelin (ENAM), have been extensively studied in mammals. More recently, a fourth protein belonging to the same family has been identified: amelotin (AMTN). AMTN has only been studied in rodents and its role during amelogenesis remains unclear.The aim of this thesis is to extend the knowledge on AMTN by studying its evolution in amniotes and its expression in the lizard Anolis carolinensis.AMTN sequences from many amniote species have been extracted from databases or obtained by PCR, and analyzed. Those analyses allowed us to reveal differences in the gene structure and to highlight residues that were conserved during mammalian or amniote evolution. These conserved amino acids are essential to the structure and/or function of the protein.The expression of AMTN and of AMEL, AMBN and ENAM has been studied by in situ hybridization on lizard jaw sections. Comparison of the expression pattern of these genes during amelogenesis in the lizard with that described in rodents points to similarities (AMEL, AMBN and ENAM) but also to important differences, especially in the spatio-temporal expression of AMTN. In order to better understand AMTN evolution in tetrapods, I studied its expression in an amphibian (Pleurodeles waltl) and a marsupial (Monodelphis domestica).Taken together, these results suggest a link between the evolution of AMTN gene structure (loss of exons and of functional domains in mammals) and its expression (early in non-mammals versus late in mammals) with the emergence of prismatic structure of enamel in early mammals.
La formation de l'émail dentaire met en jeu des phosphoprotéines sécrétées liant le calcium. Parmi celles-ci figurent amélogénine (AMEL), améloblastine (AMBN) et énaméline (ENAM), qui ont fait l'objet de nombreuses études chez les mammifères. Plus récemment, une quatrième protéine de la même famille a été découverte, l'amélotine (AMTN). Elle n'a été étudiée que chez les rongeurs et son rôle au cours de l'amélogenèse reste mal défini. L'objectif de cette thèse est d'élargir les connaissances sur AMTN en étudiant son évolution chez les amniotes et son expression au cours de l'amélogenèse chez le lézard Anolis carolinensis. Les séquences d'AMTN d'un grand nombre d'amniotes ont été extraites des bases de données ou obtenues par PCR, et analysées. Ces analyses ont mis en évidence différentes structures géniques et des acides aminés très conservés au cours de l'évolution. Cette conservation indique qu'ils sont essentiels à la structure ou à la fonction de la protéine. L'expression d'AMTN ainsi que celle d'AMEL, AMBN et ENAM ont été étudiées par hybridation in situ sur des coupes de mâchoires de lézard. La comparaison des patrons d'expression chez le lézard avec ceux décrits chez la souris a révélé des différences dans l'expression spatio-temporelle d'AMTN. De ce fait, afin de mieux comprendre l'évolution de ce gène, son expression a été étudiée chez un amphibien (Pleurodeles waltl) et un marsupial (Monodelphis domestica).Ces travaux suggère un lien entre l'évolution de la structure génique d'AMTN (perte d'exons et de domaines fonctionnels) et de son expression (précoce versus tardive) avec l'émergence de la structure prismatique de l'émail chez les mammifères.
https://tel.archives-ouvertes.fr/tel-01154518

NNT : 2015PA066066
tel-01154518
https://tel.archives-ouvertes.fr/tel-01154518
https://tel.archives-ouvertes.fr/tel-01154518/document
https://tel.archives-ouvertes.fr/tel-01154518/file/2015PA066066.pdf

Extrait de : L'illustration, n°277, p. 119-121
Résumé : Article et photographies 4 p.
Siècle(s) traité(s) : 20
Droits : Domaine public
Provenance : ORkidé|Fonds privé Pierre Rostan
Permalien : http://www.manioc.org/patrimon/ORK12155
ORK12155

Éditeur(s) : Paris : Association d'imprimeurs
Siècle(s) traité(s) : 20
Droits : Domaine public
Provenance : Collectivité territoriale de Guyane. Bibliothèque Alexandre-Franconie
Permalien : http://www.manioc.org/patrimon/FRA12350
FRA12350

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The last step of oestrogen biosynthesis is catalyzed by the enzyme aromatase, the product of the cyp19a1 gene. In vertebrates, cyp19a1 is expressed in the brain resulting in a local oestrogen production that seems important not only for the control of reproduction-related circuits and sexual behaviour, but also for the regulation of neural development, synaptic plasticity and cell survival. In adult amphibians, the precise sites of expression of cyp19a1 in the brain have not been investigated which prevents proper understanding of its potential physiological functions. The present study aimed at examining the precise neuroanatomical distribution of cyp19a1 transcripts in adult brains of both male and female Xenopus. We found that cyp19a1 expression is highly regionalized in the brains of both sexes. The highest expression was found in the anterior part of the preoptic area and in the caudal hypothalamus, but significant levels of cyp19a1 transcripts were also found in the supraoptic paraventricular and suprachiasmatic areas, and in brain regions corresponding to the septum, bed nucleus of the stria terminalis and amygdala. Importantly, no obvious difference between male and female Xenopus was detected at the level of cyp19a1 transcripts. Additionally, in the brain of adult Xenopus, cyp19a1 transcripts were detected in neurons, and not in glial cells. These data and those available in other vertebrates on cyp19a1/aromatase expression suggest that, with the intriguing exception of teleost fishes, cyp19a1 was under strong evolutionary conservation with respect to its sites of expression and the nature of the cells in which it is expressed
ISSN: 0016-6480

hal-01187140
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01187140
DOI : 10.1016/j.ygcen.2015.08.008
PUBMED : 26255686

Éditeur(s) : HAL CCSD Wiley Open Access
Résumé : Biodiversity continues to decline in the face of increasing anthropogenic pressures such as habitat destruction, exploitation, pollution and introduction of alien species. Existing global databases of species' threat status or population time series are dominated by charismatic species. The collation of datasets with broad taxonomic and biogeographic extents, and that support computation of a range of biodiversity indicators, is necessary to enable better understanding of historical declines and to project - and avert - future declines. We describe and assess a new database of more than 1.6 million samples from 78 countries representing over 28,000 species, collated from existing spatial comparisons of local-scale biodiversity exposed to different intensities and types of anthropogenic pressures, from terrestrial sites around the world. The database contains measurements taken in 208 (of 814) ecoregions, 13 (of 14) biomes, 25 (of 35) biodiversity hotspots and 16 (of 17) megadiverse countries. The database contains more than 1% of the total number of all species described, and more than 1% of the described species within many taxonomic groups - including flowering plants, gymnosperms, birds, mammals, reptiles, amphibians, beetles, lepidopterans and hymenopterans. The dataset, which is still being added to, is therefore already considerably larger and more representative than those used by previous quantitative models of biodiversity trends and responses. The database is being assembled as part of the PREDICTS project (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems - ). We make site-level summary data available alongside this article. The full database will be publicly available in 2015.
ISSN: 2045-7758

hal-01204216
https://hal.archives-ouvertes.fr/hal-01204216
DOI : 10.1002/ece3.1303
PRODINRA : 280886

Éditeur(s) : Paris : Lenoir
Extrait de : Paris : Lenoir-01-01
Siècle(s) traité(s) : 18
Droits : Domaine public
Provenance : Collectivité territoriale de Martinique. Bibliothèque Schoelcher
Permalien : http://www.manioc.org/patrimon/SCH13063
SCH13063

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
Cytochrome P450 aromatase (P450arom; aromatase) is a microsomal enzyme involved in the production of endogeneous sex steroids by converting testosterone into oestradiol. Aromatase is the product of the cyp19a1 gene and plays a crucial role in the sexual differentiation of the brain and in the regulation of reproductive functions. In the brain of mammals and birds, expression of cyp19a1 has been demonstrated in neuronal populations of the telencephalon and diencephalon. By contrast, a wealth of evidence established that, in teleost fishes, aromatase expression in the brain is restricted to radial glial cells. The present study investigated the precise neuroanatomical distribution of cyp19a1 mRNA during brain development in Xenopus laevis (late embryonic to juvenile stages). For this purpose, we used in situ hybridisation alone or combined with the detection of a proliferative (proliferating cell nuclear antigen), glial (brain lipid binding protein, Vimentin) or neuronal (acetylated tubulin; HuC/D; NeuroβTubulin) markers. We provide evidence that cyp19a1 expression in the brain is initiated from the very early larval stage and remains strongly detected until the juvenile and adult stages. At all stages analysed, we found the highest expression of cyp19a1 in the preoptic area and the hypothalamus compared to the rest of the brain. In these two brain regions, cyp19a1-positive cells were never detected in the ventricular layers. Indeed, no co-labelling could be observed with radial glial (brain lipid binding protein, Vimentin) or dividing progenitors (proliferating cell nuclear antigen) markers. By contrast, cyp19a1-positive cells perfectly matched with the distribution of post-mitotic neurones as shown by the use of specific markers (HuC/D, acetylated tubulin and NeuroβTubulin). These data suggest that, similar to that found in other tetrapods, aromatase in the brain of amphibians is found in post-mitotic neurones and not in radial glia as reported in teleosts.
ISSN: 0953-8194

hal-00994513
https://hal-univ-rennes1.archives-ouvertes.fr/hal-00994513
DOI : 10.1111/jne.12142
PUBMED : 24612124

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) : HAL CCSD Universidad Complutense de Madrid
Résumé : The Lodève Permian synrift sequence is represented by thick stacked climate-controled playa cycles which have been constrained by structural, sedimentological, geochemical and paleontological processes. The present paper merges the different results in order to better constrain the dynamics and palaeoecologycal evolution of the playa system from Late Cisuralian to Early Lopingian time. In this depositional environment, thining upwards sheet-flood sequences represent flooding events; they are relayed by ephemeral ponding, suspension settling and limited carbonate precipitation accompanied by large amounts of shallow to subaerial sedimentary structures... (Ver más) (current and wind ripples, desiccation cracks, rain drops, etc.). The aridity of the climate contrasts with the surprising abundance of the fauna encountered into carbonate-rich silty-clay playa-lake deposits. Ephemeral pools are colonized by numerous shellfish: Choncostraca, Triopsids, and Insects, which led to intense burrowing of the overbank deposits (Scoyenia facies). Tetrapods are common and dominated by several types of reptiles after footprints: Pelycosauria, Parareptilia and Lepidosauria in the Rabejac Fm, and Mammalian reptiles (Therapsida) on the top of the fluvial deposits of the Salagou Fm near La Lieude farm. In addition, elements of a weighty herbivorous Pelycosaurian and a small amphibian Tupilakosaurid, only described in the Triassic before, have been also found in the Upper part of the Permian series of this sector.
ISSN: 1698-6180

hal-00411539
https://hal.archives-ouvertes.fr/hal-00411539

Éditeur(s) : HAL CCSD SAGE Publications (UK and US)
Résumé : International audience
Amelogenin gene organization varies from 6 exons (1,2,3,5,6,7) in amphibians and sauropsids to 10 in rodents. The additional exons are exons 4, 8, 9, and ``4b'', the latter being as yet unidentified in AMELX transcripts. To learn more about the evolutionary origin of these exons, we used an in silico approach to find them in 39 tetrapod genomes. AMEL organization with 6 exons was the ancestral condition. Exon 4 was created in an ancestral therian (marsupials + placentals), then exon 9 in an ancestral placental, and finally exons ``4b'' and 8 in rodents, after divergence of the squirrel lineage. These exons were either inactivated in some lineages or remained functional: Exon 4 is functional from artiodactyls onward; exon 9 is known, to date, only in rodents, but could be coding in various mammals; and exon ``4b'' was probably coding in some rodents. We performed PCR of cDNA isolated from mouse and human tooth buds to identify the presence of these transcripts. A sequence analogous to exon ``4b'', and to exon 9, could not be amplified from the respective tooth cDNA, indicating that even though sequences similar to these exons are present, they are not transcribed in these species.
ISSN: 0022-0345

hal-01545487
https://hal.archives-ouvertes.fr/hal-01545487
DOI : 10.1177/0022034511423399

Éditeur(s) : HAL CCSD
Résumé : International audience
Estrogens affect brain development of vertebrates, not only by impacting activity and morphology of existing circuits, but also by modulating embryonic and adult neurogenesis. The issue is complex as estrogens can not only originate from peripheral tissues, but also be locally produced within the brain itself due to local aromatization of androgens. In this respect, teleost fishes are quite unique because aromatase is expressed exclusively in radial glial cells, which represent pluripotent cells in the brain of all vertebrates. Expression of aromatase in the brain of fish is also strongly stimulated by estrogens and some androgens. This creates a very intriguing positive auto-regulatory loop leading to dramatic aromatase expression in sexually mature fish with elevated levels of circulating steroids. Looking at the effects of estrogens or anti-estrogens in the brain of adult zebrafish showed that estrogens inhibit rather than stimulate cell proliferation and newborn cell migration. The functional meaning of these observations is still unclear, but these data suggest that the brain of fish is experiencing constant remodeling under the influence of circulating steroids and brain-derived neurosteroids, possibly permitting a diversification of sexual strategies, notably hermaphroditism. Recent data in frogs indicate that aromatase expression is limited to neurons and do not concern radial glial cells. Thus, until now, there is no other example of vertebrates in which radial progenitors express aromatase. This raises the question of when and why these new features were gained and what are their adaptive benefits. This article is part of a Special Issue entitled: Nuclear receptors in animal development.
Biochimica et Biophysica Acta (BBA) - Gene Regulatory Mechanisms

Droits : info:eu-repo/semantics/OpenAccess
hal-01102449
https://hal.archives-ouvertes.fr/hal-01102449
https://hal.archives-ouvertes.fr/hal-01102449/document
https://hal.archives-ouvertes.fr/hal-01102449/file/Coumailleau%20et%20al%20final%20manuscript.pdf
DOI : 10.1016/j.bbagrm.2014.07.002

Éditeur(s) : Paris : Morizot
Résumé : Nouvelle édition
Il manque les tomes : 1:Histoire de la géographie 3:Asie(suite) 8:Europe(suite) et Table générale Chaque tome concernant des pays précis , ils sont indépendant les uns des autres
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/FRA11193
FRA11193

Éditeur(s) : Londres
Siècle(s) traité(s) : 15
Provenance : Archives départementales de Guadeloupe
Permalien : http://www.manioc.org/patrimon/ADG18250
ADG18250

Éditeur(s) : Paris : Librairie Hachette
Résumé : Jules Belin de Launay (1814-1883) était un historien, géographe, journaliste, typographe et enseignant. L'ouvrage contient 16 illustrations sur le Brésil. Troisième édition.
Siècle(s) traité(s) : 19
Droits : Domaine public
Provenance : Collectivité territoriale de Guyane. Bibliothèque Alexandre-Franconie
Permalien : http://www.manioc.org/patrimon/FRA11203
FRA11203

Éditeur(s) : Amsterdam ; Paris : chez la Vve Duchesne, Librairie
Siècle(s) traité(s) : 18
Droits : Domaine public
Provenance : Université Toulouse 1 Capitole. Service Commun de la Documentation
Permalien : http://www.manioc.org/patrimon/TLS17100
TLS17100

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
Amelotin (AMTN) is an ameloblast-secreted protein that belongs to the secretory calcium-binding phosphoprotein family, which also includes the enamel matrix proteins amelogenin, ameloblastin and enamelin. Although AMTN is supposed to play an important role in enamel formation, data were long limited to the rodents, in which it is expressed during the maturation stage. Recent comparative studies in sauropsids and amphibians revealed that (i) AMTN was expressed earlier, i.e. as soon as ameloblasts are depositing the enamel matrix, and (ii) AMTN structure was different, a change which mostly resulted from an intraexonic splicing in the large exon 8 of an ancestral mammal. The present study was performed to know whether the differences in AMTN structure and expression in rodents compared to non-mammalian tetrapods dated back to an early ancestral mammal or were acquired later in mammalian evolution. We sequenced, assembled and screened the jaw transcriptome of a neonate opossum Monodelphis domestica, a marsupial. We found two AMTN transcripts. Variant 1, representing 70.8% of AMTN transcripts, displayed the structure known in rodents, whereas variant 2 (29.2%) exhibited the nonmammalian tetrapod structure. Then, we studied AMTN expression during amelogenesis in a neonate specimen. We obtained similar data as those reported in rodents. These findings indicate that more than 180 million years ago, before the divergence of marsupials and placentals, changes occurred in AMTN function and structure. The spatiotemporal expression was delayed to the maturation stage of amelogenesis and the intraexonic splicing gave rise to isoform 1, encoded by variant 1 and lacking the RGD motif. The ancestral isoform 2, housing the RGD, was initially conserved, as demonstrated here in a marsupial, then secondarily lost in the placental lineages. These findings bring new elements towards our understanding of the non-prismatic to prismatic enamel transition that occurred at the onset of mammals.
ISSN: 1932-6203

Droits : http://creativecommons.org/licenses/by/
hal-01233552
https://hal.archives-ouvertes.fr/hal-01233552
https://hal.archives-ouvertes.fr/hal-01233552/document
https://hal.archives-ouvertes.fr/hal-01233552/file/journal.pone.0133314.pdf
DOI : 10.1371/journal.pone.0133314

Éditeur(s) : HAL CCSD Springer
Résumé :  
Nineteen novel microsatellite loci were isolated from Adenomera andreae, a widespread Amazonian frog considered to be a species complex. Three multiplex kits were optimized. Genetic diversity was assessed in 66 individuals sampled in three populations along the West of the Approuague River catchment (French Guiana). We also tested the multiplex kits in four other Adenomera and nine Leptodactylus species with 43.4 and 17.5% success respectively.
ISSN: 1877-7252

hal-01032133
https://hal.archives-ouvertes.fr/hal-01032133
DOI : 10.1007/s12686-009-9053-4

Éditeur(s) : Genève : chez Jean-Leonard Pellet

Droits : Domaine public
Provenance : Université de Nantes. Service commun de la documentation
Permalien : http://www.manioc.org/patrimon/NAN13054-10
NAN13054-10

Éditeur(s) : [S.l.] : L.G. Stahl
Siècle(s) traité(s) : 20
Droits : Domaine public
Provenance : Archives départementales de Guadeloupe
Permalien : http://www.manioc.org/patrimon/ADG18107
ADG18107

Éditeur(s) : Paris : Plon
Siècle(s) traité(s) : 19
Droits : Domaine public
Provenance : Collectivité territoriale de Guyane. Bibliothèque Alexandre-Franconie
Permalien : http://www.manioc.org/patrimon/FRA12343
FRA12343