Éditeur(s) : CRILLASH : Centre de Recherches Interdisciplinaires en Lettres, Langues, Arts et Sciences Humaines
Extrait de : "Réel merveilleux, réalisme merveilleux, réalisme magique et baroque (III)" : journée d'étude, le 7 mai 2015. Université des Antilles et de la Guyane
Description : La migration, les déplacements incessants des personnages constituent une thématique forte dans mon travail d'écrivain et participent d'une esthétique que je nomme vagabondage. Ces déplacements sont parfois liés à des nécessités économiques, mais plus souvent à une pulsion de l'ailleurs, qui finit, chez certains, par prendre la forme d'une véritable obsession. Les données de cette obsession du déplacement ? et de son pendant, l'ailleurs ? sont présentes dès mon premier recueil de poèmes. Toutefois, loin de la subir, certains personnages finissent par s'en servir pour constituer une géographie personnelle. Faite de nostalgie et de rêves. Un lieu toujours repoussé plus loin, qui participe d'un choix de l'individu, de sa liberté, liée de manière intrinsèque à la prise de conscience de son humanité et aussi du caractère éphémère de celle-ci. En ce sens, l'idée de vagabondage se différencie d'autres concepts proches comme l'errance, le nomadisme ou encore l'exil. Elle est surtout liée à ce que je nomme le pays-temps, une idée développée dans l'épilogue de mon roman Le crayon du bon Dieu n'a pas de gomme. Dans l'esprit du narrateur, le Temps est fait d'étapes, de «lieux» successifs qu'on n'habite jamais qu'une fois. C'est alors lui qui définit l'individu et non plus l'espace, auquel il se substitue. Cette obsession du Temps, présente aussi bien dans ma prose que dans ma poésie, relève d'une thématique personnelle. Elle y rejoint l'idée de vagabondage, ce désir inconscient de vouloir arrêter sinon le Temps, du moins de ne pas le voir passer.
Siècle(s) traité(s) : 21
Droits : CC-BY-NC-ND - Attribution - Pas d'utilisation commerciale - Pas de modification
Permalien : http://www.manioc.org/fichiers/V15207
V15207

Éditeur(s) : CRPLC : Centre de Recherche sur les Pouvoirs Locaux dans la Caraïbe
Extrait de : "Etat et sociétés en Outre-mer" : colloque, les 27 et 28 novembre 2014. Université des Antilles et de la Guyane
Description : Il sera question ici de "décrypter sur le plan discursif les réajustements de sens initiés par le mouvement social de 2009." L'intérêt se portera d'abord sur la construction des catégories et des frontières puis sur la déconstruction de celles-ci.
Siècle(s) traité(s) : 21
Droits : CC-BY-NC-ND - Attribution - Pas d'utilisation commerciale - Pas de modification
Permalien : http://www.manioc.org/fichiers/V15294
V15294

Éditeur(s) : Yale University
Résumé : Sea-surface temperature images of the coastal upwelling regions off Northwest Africa show that the core of upwelling is sometimes located far from the coast. This has been documented in three regions that share a common feature, namely a wide and shallow continental shelf. This upwelling feature plays a key role in the ecology of the Canary Current System. It creates an innerfront which provides retention for biological material, e.g. fish eggs and larvae, in the highly productive nearshore environment. An analytical model has been developed based on a two dimensional extension of Ekman's solution. The linear and steady response of a homogeneous ocean forced by an upwelling-favorable wind provides a mechanism for the upwelling separation from the coast. The merging of the surface and bottom Ekman layers induces a very weak cross-shore circulation and a "kinematic barrier" for the Ekman transport divergence. In the case of an alongshore wind, the barrier is located near the isobath h ≈ 0.4D, where D is the thickness of Ekman layers. This yields an upwelling cell which is essentially concentrated in the region 0.5D < h < 1.25D, with upwelling occurring preferentially near the isobath h ≈ 0.6D. It turns out that the cross-shore width of upwelling scales with D/S, the ratio of Ekman depth to bottom topographic slope. The application of this solution to real bathymetric profiles rationalizes, not only the offshore upwelling observations in Northwest Africa, but also the influence of topography on the cross-shelf structure of a wind-driven coastal upwelling. The model also quantifies the effect of the cross-shore wind component showing how it drives the nearshore pressure gradient adjustment and how it affects the upwelling. A linear numerical experiment reproduces the theoretical steady solution, thereby allowing investigation of the transient regime. Relaxation of the hypothesis in the numerical model validates the linear assumption of the theory and then allows investigation of the sensitivity to friction parameterizations and the influence of stratification. The latter leads to an "oscillation" of the upwelling cell with seaward migration driven by outcropping and homogeneization of the water column, and, coastal incursion driven by a "boundary layers splitting" process caused by shoreward advection of the isopycnal dome and stratification of the inner shelf.
Journal of Marine Research (Yale University), 2008-09 , Vol. 66 , N. 5 , P. 589-616

Droits : 2008 Yale University
http://archimer.ifremer.fr/doc/2008/publication-6334.pdf
DOI:10.1357/002224008787536790
http://archimer.ifremer.fr/doc/00000/6334/

Éditeur(s) : Ecole nationale supérieure agronomique de Rennes
Résumé : Describe and gain understanding on fluctuations in animal population over time and space is a central goal of population ecology. This is also crucial to ensure the sustainable management of exploited resources, particularly those with complex population dynamics such as the bluefin tuna. The goal of this work is to collect bluefin tuna catches from the ancestral Mediterranean and Atlantic trap fisheries to (i) characterise long-term fluctuations in bluefin tuna population migrating in the Mediterranean, (ii) analyse their causes et (iii) assess their implications for fisheries management. The bluefin tuna main biological and ecological characteristics are first detailed. Then, the first part presents the trap fishery, and the process of collect and validation of the historical catches. This leads to develop a data base of 54 time-series more than 20 years long, the longest ones spanning about four centuries. Mean historical catches were around 15 000 tons/year ([7 000;25 000]). Time-series are analysed in a second part. Temporal variability of trap catches may be decomposed in three components: 100-year-long periodic fluctuations, 20-year cycles and inter-annual variations. These medium- to long-term fluctuations, representing more than 50% of the variability in the time-series, were synchronous all around the western Mediterranean and adjacent North Atlantic. In contrast, short-term variability was synchronous at a local scale only. It is argued that long-term fluctuations in trap catches could be considered as a proxy for those in abundance, and a synthetic time-series is computed to depict them. Biological and ecological processes that could cause such long-term fluctuations are discussed in a third part. We tested whether long-term fluctuations in Atlantic bluefin tuna might be related to large-scale environmental changes, using long time-series of the North Atlantic Oscillation (NAO), the Length of the Day index (LOD, a proxy of the atmospheric circulation index ACI) and the temperature. Spectral analyses of trap catches, LOD and temperature displayed similar spectra with peak at low frequency, whereas those of the NAO exhibited a broad band spectrum. Regression analyses and tests of correlation did not reveal any clear relationship between trap catches on the one hand and NAO and LOD on the other hand. In contrast, long-term fluctuations in trap catches appear to be negatively and significantly related to long-term trends in temperature. Underlying processes that could explain such a relationship are discussed, with special focus on changes in migration patterns. Finally, implications of such fluctuations in term of fisheries management are discussed in a fourth part. A simulation framework, in which a simulated population dynamics model is coupled with a VPA, is built to test the pertinence of the diagnostic of stock assessment according to different scenarios on fluctuations origins and population status. In the hypothesis of fluctuations linked to variations in the recruitment, VPA appears able to reconstruct the fluctuations but the predictions may be biased if natural fluctuations are not taking into account. In the hypothesis of fluctuations linked to changes in migration pattern, VPA is not able to reconstruct the population dynamics. In a precautionary approach, quotas which follow may be unsuitable in the best case, at worst dangerous if they are defined in comparison with a reference point. The concept of cible reference points, fixe and unique over time, appears not relevant for bluefin tuna; estimate trajectory reference pertinent may prove to be more pertinent.
Décrire et comprendre les fluctuations spatio-temporelles des espèces animales constituent les enjeux majeurs de l'écologie. La question est également cruciale pour réussir la gestion durable des ressources exploitées, en particulier celle du thon rouge, grand pélagique migrateur à la dynamique complexe. L'objectif de ce travail est de collecter les captures historiques de thon rouge par les madragues méditerranéennes et proche atlantiques pour (i) caractériser les fluctuations à long terme de la population migrante en Méditerranée, (ii) étudier leur déterminisme et (iii) évaluer leurs implications en terme de gestion des pêcheries. Après avoir décrit les principales caractéristiques biologiques et écologiques du thon rouge, la première partie présente la pêcherie à la madrague, puis le processus de collecte et de validation des données historiques de captures. Ce dernier conduit à la mise en place d'une base de données de 54 séries de plus de 20 ans, dont les plus longues s'étendent sur près de 4 siècles. Les productions historiques sont estimées à environ 15 000 tonnes/an ([7 000;25 000]). Les séries historiques de captures sont analysées dans la seconde partie. Leur variabilité temporelle peut être décomposée en trois composantes : de larges cycles pseudo-séculaires, des variations périodiques d'une vingtaine d'années et des fluctuations inter-annuelles. Les fluctuations à moyen et long terme, expliquant plus de la moitié de la variance des séries, sont synchrones à l'échelle du bassin méditerranéen occidental et du proche Atlantique. La variabilité inter-annuelle, en revanche, n'est synchrone qu'à une échelle locale. On montre finalement que les fluctuations à long terme des captures peuvent être considérées comme de bons indices des tendances des abondances de la population de thons rouges migrants en Méditerranée. Une série synthétique est construite pour les décrire. Les processus biologiques et écologiques susceptibles d'être à l'origine de ces fluctuations sont discutés dans la troisième partie. L'hypothèse d'un forçage environnemental à grande échelle est testée en utilisant des indices à long terme de l'Oscillation Nord Atlantique (NAO), de la longueur du jour (LOD, un indicateur de l'indice de circulation atmosphérique ACI) et de la température. Les analyses spectrales sur les séries de captures, du LOD et des températures révèlent des spectres similaires, avec un pic sur les basses fréquences, alors que celles sur le NAO conduisent à une large bande spectrale. Les régressions et les tests de corrélations ne montrent aucune relation significative entre les captures par les madragues et le NAO et le LOD. En revanche, les fluctuations à long terme des captures apparaissent significativement et négativement corrélées avec les fluctuations à long terme des températures. Les processus sous-jacents susceptibles d'expliquer une telle relation, en particulier des changements migratoires, sont discutés. Finalement, les implications des fluctuations pour la gestion de la pêcherie sont discutées dans une quatrième partie. Un cadre de simulation, couplant un modèle de dynamique de population à une VPA, est élaboré pour tester la pertinence des diagnostics d'évaluation de stock selon différents scénarios d'origine des fluctuations et d'état de la population. Dans l'hypothèse de fluctuations liées à des variations du recrutement, la VPA apparaît capable de reconstruire les fluctuations mais les prédictions sont biaisées lorsqu'il n'est pas tenu compte des fluctuations naturelles du stock. Dans l'hypothèse de fluctuations liées à des changements migratoires, la VPA est alors incapable de reproduire la dynamique de la population. Dans une approche de précaution, les quotas qui en découlent peuvent se révéler au mieux inappropriés, au pire dangereux s'ils sont définis par rapport à un point de référence. Ce concept de point cible, fixe et unique dans le temps, apparaît inapproprié pour le thon rouge ; estimer des "trajectoires de référence" serait sans doute plus pertinent.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/2003/these-65.pdf
http://archimer.ifremer.fr/doc/00000/65/

Éditeur(s) : LC2S : Laboratoire Caribéen de Sciences Sociales
Description : Dans sa communication, Audrey Célestine, expose le bien-fondé de l'écriture de ses deux livres. En ce qui concerne « La fabrique des identités... », elle explique que l'idée est tirée de sa thèse. Celle-ci avait pour ambition de comparer les trajectoires communes de deux populations issues de migration postcoloniale : les Antillais vers la France et les Portoricains vers les Etats-Unis. Une Famille française pour sa part, est un projet personnel en tant qu'il s'agissait de décrire le parcours des ascendants de ses enfants sur trois générations en reliant leurs histoires à des problématiques liées au passé colonial, à la racialisation et à l'ascension sociale. Les sujets abordés dans les deux ouvrages sont certes différents, mais l'auteure se propose d'élucider ce qui les relie.

Droits : CC-BY-NC-ND - Attribution - Pas d'utilisation commerciale - Pas de modification
Permalien : http://www.manioc.org/fichiers/V18259
V18259

Éditeur(s) : HAL CCSD
Résumé : Croton urucurana Baillon (Euphorbiaceae), plant species popularly known in Brazil as “sangra-d’água”, is commonly found in Mato Grosso do Sul State (midwestern Brazil), where its latex is popularly used to treat several types of cancer. Despite the ethnopharmacological significance of the species, no phytochemical or cytotoxic studies of its latex have been published. In this context, the aim of the present study was to assess the cytotoxic activity of crude extracts, fractions and isolated compound from the latex of C. urucurana and to investigate the effects of crourorb A1 on the viability, apoptosis, cell cycle and cell migration of human hepatocarcinoma cell lines (Huh-7). Also, we have evaluated the viability of Huh-7 cells treated with crourorb A1 in 3D collagen gels. The cytotoxicity was detected using the sulforhodamine B (SRB) assay against six human cancer cells lines and one nontumor NIH/3T3 cell line (murine fibroblast). Studies on the mechanism of cell death of crourorb A1 were conducted in different test systems in vitro. The bioactive ethyl acetate phase obtained from the latex of C. urucurana afforded a novel cyclic peptide, [1−9-NαC]-crourorb A1, that proved active against NCIADR/ RES (ovary, multidrug-resistance phenotype) cells with the same potency as doxorubicin (positive control) and inactive up to the highest concentration tested against nontumor NIH/3T3 cells (GI50 = > 250 μg/mL). Crourorb A1 treatment decreases the cell viability of Huh-7 at dose and time dependent manner associated with induction of apoptosis by caspase 3/7 activation and increasing expression of pro-apoptotic proteins: Bak, Bid, Bax, Puma, Bim, and Bad and clived-caspase3 protein. The JNK/MAP pathway is involved in this induced cell death. Crourorb A1 effect is also associated with G2/M phase cell cycle arrest. In parallel, we observed that crourorb A1 treatment resulted in an increase of cyclin-dependent kinase (CDK1), cyclin B1 and cyclin D1 expressions. A significant reduction of Huh-7 cells migration by crourorb A1 can be assessed and we also show that cells grown on 3D collagen gels exhibited increased resistance to crourorb A1 when compared to 2D cell culture.
Croton urucurana Baillon (Euphorbiaceae), est une plante très connue et utilisée en médecine traditionnelle au Brésil, la «sangra-d’água» retrouvée dans l'État du Mato Grosso do Sul (région Centre-Ouest du Brésil). Son latex est abondamment utilisé en médecine traditionnelle dans le traitement de plusieurs types de cancer. En dépit de son importance ethnopharmacologique, on ne trouve aucune étude sur sa composition chimique ou sur sa potentielle activité anti-cancéreuse. L’objectif de ce travail a été d'évaluer l'activité cytotoxique des extraits totaux, fractions d’extraits et de molécules purifiées, isolées du latex de C. urucurana. Nous avons étudié plus particulièrement les effets du crourorb A1 sur la viabilité, l'apoptose, le cycle cellulaire et la migration de cellules issues de carcinome hépatocellulaire humaine (Huh-7). Nous avons également évalué l’effet du crourorb A1sur la viabilité des cellules Huh-7 cultivées dans les gels de collagène en 3D. L' activité cytotoxique ont été réalisées par le test à la sulforhodamine B sur six lignées cellulaire cancéreuses et sur une lignée cellulaire non cancéreuse de fibroblastes murins, les cellules NIH/3T3. L'étude phytochimique de la fraction ‘acétate d'éthyle’ du latex de C. urucurana bioguidé a permis d’obtenir un nouveau cyclopeptide que nous avons nommé [1-9-NαC]-crourorb A1. Le crourorb présente une cytotoxicité puissante sur la lignée cellulaire cancéreuse NCI-ADR/RES (ovaire, le phénotype de multirésistance) à un niveau équivalent à celle de la doxorubicine (témoin positif). Ce composé est de plus pratiquement inactif (GI50 = >250 μg/mL) sur la lignée non cancéreuse NIH/3T3. L'évaluation de la cytotoxicité in vitro du crourorb A1 (test wst1) sur les cellules Huh-7 a démontré que la viabilité des cellules est inhibée de manière dose et temps-dépendant. Nous avons mesuré une forte activation des caspases 3 et 7 et une nette augmentation de l’expression des protéines pro-apoptotiques (Bak, Bid, Bax, Puma, Bim et Bad) ainsi que de la caspase 3 clivée par le crourorb A1. Nous avons également déterminé que la voie de signalisation JNK-MAPkinase semble nécessaire à l’induction de la mort cellulaire des cellules Huh-7 traitées au crourorb A1. Le crourob A1 induit un arrêt du cycle cellulaire en phase G2/M. En parallèle, les expressions de la cycline-dépendante kinase CDK1, des cyclines B1 et D1 sont augmentées après traitement au crourorb A1. De plus, le crourorb A1 a un effet inhibiteur significatif de la migration des cellules Huh-7, en présence ou absence de mitomycine C. Nous avons également confirmé, l’effet inhibiteur du crourob A1 sur la viabilité des cellules Huh7 cultivées en 3D dans les gels de collagène 1 et démontré que les cellules cultivées en 3D semblent plus résistantes au crourorb A1 par rapport aux cultures en monocouche 2D.
Croton urucurana Baillon (Euphorbiaceae) é uma espécie arbórea conhecida popularmente no Brasil como “sangra d´água”, comumente encontrada no estado de Mato Grosso do Sul, onde seu látex tem sido utilizado na medicina popular no tratamento de vários tipos de câncer. Apesar de sua importância etnofarmacológica, não há relatos de estudos relacionados à sua composição química ou atividades anticâncer na literatura. Nesse contexto, o objetivo do presente estudo foi avaliar a atividade citotóxica de extratos, fases, frações e da substância isolada do látex de C. ururucurana e investigar os mecanismos celulares e moleculares in vitro responsáveis pela citotoxicidade da substância isolada considerando seu potencial apoptótico e influência sobre a progressão do ciclo celular em uma linhagem de hepatocarcinoma celular humano (Huh-7), bem como, os efeitos desta substância sobre a migração e viabilidade de células Huh-7 cultivadas em geis de colágeno em 3D. O ensaio de citotoxicidade in vitro foi realizado com o corante sulforrodamina B (SRB) em seis linhagens de células neoplásicas humanas e uma linhagem de células não neoplásicas NIH/3T3 (fibloblasto murinho). Os estudos de mecanismos de ação com crourorb A1 foram conduzidos em diferentes sistemas-teste in vitro. O estudo fitoquímico biomonitorado da fase bioativa acetato de etila do látex de C. urucurana resultou no isolamento de um novo ciclopeptídeo denominado [19-NαC]-crourorb A1, que apresentou potente atividade citotóxica frente à linhagem de células neoplásicas NCI-ADR/RES (ovário com fenótipo de resistência a múltiplos fármacos), com a mesma potência que a doxorrubicina (controle positivo), e foi inativa até a maior concentração testada (GI50 = >250 μg/mL) frente à linhagem de células não neoplásicas 3T3. A exposição de células Huh-7 ao crourorb A1 resultou em uma diminuição da viabilidade celular de maneira dose e tempo-dependentes. Nós observamos um aumento da atividade de caspases 3 e 7 e um aumento da expressão de proteínas próapoptóticas (Bak, Bid, Bax, Puma, Bim e Bad) e caspase 3 clivada após tratamento com crourorb A1. Além disso, observamos que a via de sinalização celular MAP/JNK foi necessária para induzir a morte celular em células Huh-7 tratadas com crourorb A1. Os efeitos de crourorb A1 foram também associados com o acúmulo de células na fase G2/M do ciclo celular. Em paralelo, as expressões da cinase dependente da ciclina (CDK1), ciclina B1 e ciclina D1 foram aumentadas após tratamento com crourorb A1. Foi demonstrado também o envolvimento de crourorb A1 na redução da migração de células Huh-7 cultivadas na presença e ausência de mitomicina C. A avaliação da viabilidade de células Huh-7 cultivadas em geis de colágeno em 3D apontou uma maior resistência destas células ao crourorb A1 quando comparadas com a cultura de células em 2D.
https://tel.archives-ouvertes.fr/tel-01478286

NNT : 2016REN1B010
tel-01478286
https://tel.archives-ouvertes.fr/tel-01478286
https://tel.archives-ouvertes.fr/tel-01478286/document
https://tel.archives-ouvertes.fr/tel-01478286/file/DE-MATOS-CANDIDO-BACANI-Priscila.pdf

Éditeur(s) : Faculté de Droit et d'Economie de la Martinique
Extrait de : "Les migrations" : table ronde, le 10 mars 2020. Université des Antilles
Description : Urdine Darius nous présente le projet ELAN (ECHANGES LINGUISTIQUES ET APPRENTISSAGE NOVATEUR PAR LA MOBILITÉ). OBJECTIF GLOBAL : -Conception d'une banque de stages à l'échelle régionale -Mise en place de bourses pour soutenir la mobilité (entrante et sortante) étudiante, enseignante et universitaire, ainsi que celle des stagiaires de la formation professionnelle et la programmation d'actions conjointes de promotion, afin d'accroître la visibilité de l'offre de formations supérieures aux Antilles -L'identification des formations universitaires d'excellence dans les Antilles, dans les Etats de l'OECS, sur les principaux campus de l'Université des West Indies et dans les deux universités partenaires en HAITI, -Une meilleure valorisation des programmes Européens de mobilité étudiante étendus aux pays non communautaires, -La diffusion aux populations des résultats positifs du projet par une communication active sur les opportunités de mobilité dans la Caraïbe

Droits : CC-BY-NC-ND - Attribution - Pas d'utilisation commerciale - Pas de modification
Permalien : http://www.manioc.org/fichiers/V20121
V20121

Éditeur(s) : HAL CCSD Nature Publishing Group
Résumé : International audience
Transmembrane CD95L (Fas ligand) can be cleaved to release a promigratory soluble ligand, cl-CD95L, which can contribute to chronic inflammation and cancer cell dissemination. The motility signaling pathway elicited by cl-CD95L remains poorly defined. Here, we show that in the presence of cl-CD95L, CD95 activates the Akt and RhoA signaling pathways, which together orchestrate an allosteric activation of the Na+/H+ exchanger NHE1. Pharmacologic inhibition of Akt or ROCK1 independently blocks the cl-CD95L-induced migration. Confirming these pharmacologic data, disruption of the Akt and ROCK1 phosphorylation sites on NHE1 decreases cell migration in cells exposed to cl-CD95L. Together, these findings demonstrate that NHE1 is a novel molecular actor in the CD95 signaling pathway that drives the cl-CD95L-induced cell migration through both the Akt and RhoA signaling pathways.
ISSN: 2045-2322

hal-01334067
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01334067
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01334067/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01334067/file/Cleaved%20FAS%20ligand%20CC-BY.pdf
DOI : 10.1038/srep28008

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
BACKGROUND: The orphan receptors COUP-TF (chicken ovalbumin upstream promoter transcription factor) I and II are members of the nuclear receptor superfamily that play distinct and critical roles in vertebrate organogenesis. The involvement of COUP-TFs in cancer development has recently been suggested by several studies but remains poorly understood. METHODS: MCF-7 breast cancer cells overexpressing COUP-TFI and human breast tumors were used to investigate the role of COUP-TFI in the regulation of CXCL12/CXCR4 signaling axis in relation to cell growth and migration. We used Immunofluorescence, western-blot, RT-PCR, Formaldehyde-assisted Isolation of Regulatory Elements (FAIRE) assays, as well as cell proliferation and migration assays. RESULTS: Previously, we showed that COUP-TFI expression is enhanced in breast cancer compared to normal tissue. Here, we report that the CXCL12/CXCR4 signaling pathway, a crucial pathway in cell growth and migration, is an endogenous target of COUP-TFI in breast cancer cells. The overexpression of COUP-TFI in MCF-7 cells inhibits the expression of the chemokine CXCL12 and markedly enhances the expression of its receptor, CXCR4. Our results demonstrate that the modification of CXCL12/CXCR4 expression by COUP-TFI is mediated by the activation of epithelial growth factor (EGF) and the EGF receptor. Furthermore, we provide evidence that these effects of COUP-TFI increase the growth and motility of MCF-7 cells in response to CXCL12. Cell migration toward a CXCL12 gradient was inhibited by AMD3100, a specific antagonist of CXCR4, or in the presence of excess CXCL12 in the cell culture medium. The expression profiles of CXCR4, CXCR7, CXCL12, and COUP-TFI mRNA in 82 breast tumors and control non-tumor samples were measured using real-time PCR. CXCR4 expression was found to be significantly increased in the tumors and correlated with the tumor grade, whereas the expression of CXCL12 was significantly decreased in the tumors compared with the healthy samples. Significantly higher COUP-TFI mRNA expression was also detected in grade 1 tumors. CONCLUSIONS: Together, our mechanistic in vitro assays and in vivo results suggest that a reduction in chemokine CXCL12 expression, with an enhancement of CXCR4 expression, provoked by COUP-TFI, could be associated with an increase in the invasive potential of breast cancer cells.
ISSN: 1471-2407

hal-01024753
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01024753
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01024753/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01024753/file/1471-2407-14-407.pdf
DOI : 10.1186/1471-2407-14-407

Éditeur(s) : HAL CCSD Nature Publishing Group
Résumé : International audience
Mantle cell lymphoma (MCL) is a hematologic neoplasm characterised by the t(11;14)(q13;q32) translocation leading to aberrant cyclin D1 expression. The cell functions of cyclin D1 depend on its partners and/or subcellular distribution, resulting in different oncogenic properties. We observed the accumulation of cyclin D1 in the cytoplasm of a subset of MCL cell lines and primary cells. In primary cells, this cytoplasmic distribution was correlated with a more frequent blastoid phenotype. We performed immunoprecipitation assays and mass spectrometry on enriched cytosolic fractions from two cell lines. The cyclin D1 interactome was found to include several factors involved in adhesion, migration and invasion. We found that the accumulation of cyclin D1 in the cytoplasm was associated with higher levels of migration and invasiveness. We also showed that MCL cells with high cytoplasmic levels of cyclin D1 engrafted more rapidly into the bone marrow, spleen, and brain in immunodeficient mice. Both migration and invasion processes, both in vivo and in vitro, were counteracted by the exportin 1 inhibitor KPT-330, which retains cyclin D1 in the nucleus. Our data reveal a role of cytoplasmic cyclin D1 in the control of MCL cell migration and invasion, and as a true operator of MCL pathogenesis.
ISSN: 2045-2322

hal-01635754
https://hal.archives-ouvertes.fr/hal-01635754
DOI : 10.1038/s41598-017-14222-1
PUBMED : 29066743

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The brain of the adult teleost fish exhibits intense neurogenic activity and an outstanding capability for brain repair. Remarkably, the brain estrogen-synthesizing enzyme, aromatase B, is strongly expressed, particularly in adult fishes, in radial glial cells, which act as progenitors. Using zebrafish, we tested the hypothesis that estrogens affect adult neurogenesis and brain regeneration by modulating the neurogenic activity of radial glial cells. To investigate this, the estrogenic environment was modified through inhibition of aromatase activity, blockade of nuclear estrogen receptors, or estrogenic treatments. Estrogens significantly decreased cell proliferation and migration at the olfactory bulbs/telencephalon junction and in the mediobasal hypothalamus. It also appears that cell survival is reduced at the olfactory bulbs/telencephalon junction. We also developed a model of telencephalic lesion to assess the role of aromatase and estrogens in brain repair. Proliferation increased rapidly immediately after the lesion in the parenchyma of the injured telencephalon, while proliferation at the ventricular surface appeared after 48 h and peaked at 7 days. At this time, most proliferative cells express Sox2, however, none of these Sox2 positive cells correspond to aromatase B-positive radial glial cells. Interestingly, aromatase B expression was significantly reduced 48 h and 7 days after the injury, but surprisingly, at 72 h after lesion, aromatase B expression appeared de novo expressed in parenchyma cells, suggesting a role for this ectopic expression of aromatase in brain repair mechanisms. Altogether these data suggest that estrogens modulate adult, but not reparative neurogenesis, in zebrafish.
ISSN: 0018-506X

inserm-00831715
http://www.hal.inserm.fr/inserm-00831715
DOI : 10.1016/j.yhbeh.2012.04.003
PUBMED : 22521210

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Secondary migration is defined as the movement of hydrocarbons through relatively permeable rocks from source to trap: a two-phase flow within a porous medium. Depending on the geometry and capillary pressure distributions of carrier beds, secondary migration has both vertical and lateral components. The present paper focuses on that part of the migration where the movement is mainly vertical. Its objective is to propose a description of the dynamics governing the vertical part of secondary migration based on the main physical aspects of two-phase flow in a homogeneous porous medium. The study is illustrated by laboratory observations performed in a vertical, 2-D Hele-Shaw cell filled with a transparent porous medium where the flow of dyed oil invading a wetting fluid is visually observed. These observations help us to understand the effect of buoyant, capillary and viscous forces on the resulting flow, the relative importance of which is characterized by non-dimensional numbers. Extrapolating these observations to natural media, it is proposed that vertical secondary migration can be described as a percolation of disconnected and vertically-elongated stringers. These stringers do not move continuously but as a succession of snap-off and re-feeding events which result in a jerky upward movement. Using parameters characterizing the physical properties of the fluid and of the porous medium, the geometry and the dynamic behavior of the stringers are estimated. The width of stringers occurring during secondary migration in geological media is centimetric and their vertical size ranges from several centimeters to a few meters. An upper limit of the mean upward velocity of stringers is proposed, as well as an estimate of their spatial density and of the minimum, average horizontal distance (decametric) between two stringers. The stringers are sparsely distributed, resulting in a low average oil loss and a high efficiency of the vertical migration process.
ISSN: 0264-8172

hal-00831370
https://hal.archives-ouvertes.fr/hal-00831370
https://hal.archives-ouvertes.fr/hal-00831370/document
https://hal.archives-ouvertes.fr/hal-00831370/file/pekins-V-edited.pdf
DOI : 10.1016/j.marpetgeo.2013.04.020

Éditeur(s) : ECMEA : Etudes Croisées des Mondes Européens et Américains CRILLASH : Centre de Recherches Interdisciplinaires en Lettres, Langues, Arts et Sciences Humaines Université des Antilles. Service commun de la documentation
Extrait de : "Terres promises, représentations et imaginaires" : colloque, du 25 au 27 novembre 2015. Université des Antilles
Description : Dans les trois romans qui feront l'objet de cette communication, on verra comment pour parler des sociétés du Nouveau Monde (en particulier, celle du bassin amazonien) mais aussi de leur matrice européenne, les écrivains ont su combiner les diverses composantes du mythe de la terre promise avec la thématique de l'inceste, forme suprême de la transgression. C'est ainsi que l'on fera apparaître comment l'inceste introduit fragilité et précarité dans les structures créées par les colons des Amériques et leurs divers alliés, mais encore comment il met à mal l'idéologie raciste développée par la métropole à l'égard du migrant noir. En outre, excellent révélateur des rapports de domination en tous genres, le thème de l'inceste apporte un cinglant démenti à l'utopie portée par le mythe de la terre promise.
Siècle(s) traité(s) : 20
Droits : CC-BY-NC-ND - Attribution - Pas d'utilisation commerciale - Pas de modification
Permalien : http://www.manioc.org/fichiers/V16090
V16090

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
The mucosal events of HIV transmission have been extensively studied, but the role of infected cells present in the genital and rectal secretions, and in the semen, in particular, remains a matter of debate. As a prerequisite to a thorough in vivo investigation of the early transmission events through infected cells, we characterized in detail by multi-parameter flow cytometry the changes in macaque seminal leukocytes during SIVmac251 infection, focusing on T cells, macrophages and dendritic cells. Using immunocytofluorescence targeting SIV proteins and real-time quantitative PCR targeting SIV DNA, we investigated the nature of the infected cells on sorted semen leukocytes from macaques at different stages of infection. Finally, we cocultured semen CD4(+) T cells and macrophages with a cell line permissive to SIV infection to assess their infectivity in vitro. We found that primary infection induced strong local inflammation, which was associated with an increase in the number of leukocytes in semen, both factors having the potential to favor cell-associated virus transmission. Semen CD4(+) T cells and macrophages were productively infected at all stages of infection and were infectious in vitro. Lymphocytes had a mucosal phenotype and expressed activation (CD69 & HLA-DR) and migration (CCR5, CXCR4, LFA-1) markers. CD69 expression was increased in semen T cells by SIV infection, at all stages of infection. Macrophages predominated at all stages and expressed CD4, CCR5, MAC-1 and LFA-1. Altogether, we demonstrated that semen contains the two major SIV-target cells (CD4+ T cells and macrophages). Both cell types can be productively infected at all stages of SIV infection and are endowed with markers that may facilitate transmission of infection during sexual exposure.
ISSN: 1553-7366

hal-00955292
https://hal-univ-rennes1.archives-ouvertes.fr/hal-00955292
https://hal-univ-rennes1.archives-ouvertes.fr/hal-00955292/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-00955292/file/Semen_CD4_T-accepted.pdf
PUBMED : 24348253

Éditeur(s) : HAL CCSD Elsevier
Résumé : Thanks to Dr M. Blanchard-Desce (UMR CNRS 5255, University of Bordeaux, France), who kindly provided us with fluorescent dye RS19 and the PIXEL, MRIc, flow cytometry and H2P2 platforms (SFR Biosit, UMS CNRS 3480/US INSERM 018, Rennes).
International audience
[1-9-NαC]-crourorb A1 is a cyclic peptide isolated from Croton urucurana Baillon latex, found in midwestern Brazil, that has been shown to exert cytotoxic effects against a panel of cancer cell lines. However, the underlying mechanisms responsible for the crourorb A1-induced cytotoxicity in cancer cells remain unknown. In this study, the effects of crourorb A1 on the viability, apoptosis, cell cycle and migration of Huh-7 (human hepatocarcinoma) cells were investigated. We evaluated the viability of Huh-7 cells treated with crourorb A1 in 2D and 3D collagen cultures and found that cells in 3D culture exhibited increased resistance to crourorb A1 compared to cells in 2D culture (IC50: 62μg/ml versus 35.75μg/ml). Crourorb A1 treatment decreases the viability of Huh-7 cells in a dose- and time-dependent manner and is associated with the induction of apoptosis, in the absence of necrotic cells, through the activation of caspase-3/7 and increased expression of the pro-apoptotic proteins Bak, Bid, Bax, Puma, Bim, and Bad. The effects of crourorb A1 are also associated with G2/M phase cell cycle arrest and increases in cyclin-dependent kinase (CDK1) and cyclin B1 expression. A significant reduction in Huh-7 cell migration induced by crourorb A1 was also observed in the presence of mitomycin C. Finally, we showed that the JNK/MAP pathway, but not ERK signaling, is involved in crourorb A1-induced hepatocarcinoma cell mortality.
ISSN: 0378-4274

hal-01526429
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01526429
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01526429/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01526429/file/de%20Matos%20C%C3%A2ndido-Bacani%20et%20al.%20-%20%5B1%E2%80%939-N%CE%B1C%5D-crourorb%20A1%20isolated%20from%20Croton%20urucura.pdf
DOI : 10.1016/j.toxlet.2017.03.020

Éditeur(s) : HAL CCSD IOS Press
Résumé : International audience
Cancer is generally conceived as a dedifferentiation process in which quiescent post-mitotic differentiated cells acquire stem-like properties and the capacity to proliferate. This view holds for the initial stages of carcinogenesis but is more questionable for advanced stages when the cells can transdifferentiate into the contractile phenotype associated to migration and metastasis. Singularly from this perspective, the hallmark of the most aggressive cancers would correspond to a genuine differentiation status, even if it is different from the original one. This seeming paradox could help reconciling discrepancies in the literature about the pro-or anti-tumoral functions of candidate molecules involved in cancer and whose actual effects depend on the tumoral grade. These ambiguities which are likely to concern a myriad of molecules and pathways, are illustrated here with the selected examples of chromatin epigenetics and myocardin-related transcription factors, using the human MCF10A and MCF7 breast cancer cells. Self-renewing stem like cells are characterized by a loose chromatin with low levels of the H3K9 trimetylation, but high levels of this mark can also appear in cancer cells acquiring a contractile-type differentiation state associated to metastasis. Similarly, the myocardin-related transcription factor MRTF-A is involved in metastasis and epithelial-mesenchymal transition, whereas this factor is naturally enriched in the quiescent cells which are precisely the most resistant to cancer: cardiomyocytes. These seeming paradoxes reflect the bistable epigenetic landscape of cancer in which dedifferentiated self-renewing and differentiated migrating states are incompatible at the single cell level, though coexisting at the population level. © 2016-IOS Press and the authors. All rights reserved.
ISSN: 0888-6008

hal-01367146
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01367146
DOI : 10.3233/BD-150210
PUBMED : 27177343

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
: In non-mammalian vertebrates, serotonin (5-HT)-producing neurons exist in the paraventricular organ (PVO), a diencephalic structure containing cerebrospinal fluid (CSF)-contacting neurons exhibiting 5-HT or dopamine (DA) immunoreactivity. Because the brain of the adult teleost is known for its neurogenic activity supported, for a large part, by radial glial progenitors, this study addresses the origin of newborn 5-HT neurons in the hypothalamus of adult zebrafish. In this species, the PVO exhibits numerous radial glial cells (RGCs) whose somata are located at a certain distance from the ventricle. To study relationships between RGCs and 5-HT CSF-contacting neurons, we performed 5-HT immunohistochemistry in transgenic tg(cyp19a1b-GFP) zebrafish in which RGCs are labelled with GFP under the control of the cyp19a1b promoter. We show that the somata of the 5-HT neurons are located closer to the ventricle than those of RGCs. RGCs extend towards the ventricle cytoplasmic processes that form a continuous barrier along the ventricular surface. In turn, 5-HT neurons contact the CSF via processes that cross this barrier through small pores. Further experiments using proliferating cell nuclear antigen or 5-bromo-2'-deoxyuridine indicate that RGCs proliferate and give birth to 5-HT neurons migrating centripetally instead of centrifugally as in other brain regions. Furthermore, treatment of adult zebrafish with tryptophan hydroxylase inhibitor causes a significant decrease in the number of proliferating cells in the PVO, but not in the mediobasal hypothalamus. These data point to the PVO as an intriguing region in which 5-HT appears to promote genesis of 5-HT neurons that accumulate along the brain ventricles and contact the CSF.
ISSN: 0953-816X

inserm-00866212
http://www.hal.inserm.fr/inserm-00866212
DOI : 10.1111/ejn.12348
PUBMED : 23981075

Éditeur(s) : Université des Antilles Études caribéennes
Résumé : Les constructions socio-historiques et identitaires qui eurent lieu en Amérique durant l’époque coloniale furent si diverses qu’il s’avère difficile –et surtout impropre- de projeter une vision unique sur des espaces qui furent réunis sous l’étendard d’un pays ou d’une nation. La côte de la Mosquitia centraméricaine est l’un de ces exemples qui montrent cette diversité de constructions. La côte de la Mosquitia s’est construite à travers les siècles colonisateurs, se nourrissant de contacts, d’alliances et d’apports étrangers divers qui firent d’elle un espace autonome avec une histoire propre. Une histoire qui se détacha de l’histoire coloniale espagnole pour se rapprocher de celle de l’espace caraïbe.
The historic structures of socio-cultural identities that developed during the American colonial period were so vastly diverse that it would be difficult and inaccurate to project a homogenic view of regions that were integrated under the flag of a country or nation, the Central America Mosquito Coast illustrates that diversity. The Mosquitia as a historic entity experienced a process of construction which had as foundation partnerships and diverse contributions from foreign travelers. These contributions transformed the Mosquitia in a sovereign territory with its own historic heritage. This historic heritage distance itself from the colonial history to integrate the Caribbean history.
Las construcciones históricas, de identidades sociales y culturales que se desarrollaron en América durante la época colonial fueron tan diversas que sería difícil – y sobre todo impropio- proyectar una imagen homogénea de espacios que fueron reunidos bajo la bandera de un país o de una nación. La costa de la Mosquitia es uno de esos ejemplos que ilustran esa diversidad de construcciones. La costa de la Mosquitia –como entidad histórica- se formó durante la época colonial a través de contactos, de alianzas y de influencias extranjeras diversas que la convirtieron en un espacio autónomo, con una historia propia. Una historia que se distanció de la historia colonial para integrarse a la historia caribeña.
La Mosquitia
Honduras
Caraïbe

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.6053
http://journals.openedition.org/etudescaribeennes/6053

Éditeur(s) : Université des Antilles Études caribéennes
Résumé : Le lien entre migration et Antilles françaises est souvent traité en termes d’émigration insulaire vers l’Hexagone. En effet, les flux les plus nombreux correspondent encore à ce mouvement centripète qui s’explique par une situation sociale tendue du fait de l’inadaptation entre l’offre de travail et les jeunes adultes en trop grand nombre. Pourtant les mobilités venant de Métropole existent avec le retour des Antillais au pays. Les Antilles attirent aussi les Métropolitains. La tertiairisation de l’économie, les investissements des grandes sociétés françaises ainsi que les dernières lois de défiscalisation ou celles concernant la création d’entreprises semblent favorisent le mouvement. L’article se propose d’analyser les moteurs de ces nouvelles formes de circulation migratoire entre la France métropolitaine et la Martinique, ainsi que l’insertion économique et les territorialités spécifiques des nouveaux acteurs.
The migration-West Indies nexus is often dealt with in terms of insular emigration towards Metropolitan France. Indeed, most of the flows are still characterised by a centripetal move that can be accounted for by the hiatus between job supply and the demographic importance of the youth. Nonetheless, Metropolitan-origin mobility exist with West Indian return migration as well as Metropolitan French migration. The boom of the service economy, investments from large French firms and recent advantageous fiscal laws favour this pattern. The article seeks to analyse the new driving forces behind the circular movement between Metropolitan France and Martinique, as well as the economic insertion and the specific territorialities of the new actors.

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.932
http://journals.openedition.org/etudescaribeennes/932

Éditeur(s) : HAL CCSD Taylor & Francis (Routledge)
Résumé : International audience
Border areas are particular “hot spots” generating high levels of HIV vulnerability and facing great challenges to control epidemics. The objective of this study is to describe the sociodemographic, clinical and biological profiles of newly HIV diagnosed people at the French Guiana - Suriname border, to construct an HIV care cascade and compare it with the Surinamese one. HIV-patients aged over 15 years newly diagnosed in western French Guiana in 2011 and 2012 were included in a retrospective cohort study. Patients were identified using different sources (n=121). The male-to-female ratio was 0.8, 85% of the patients were of foreign origin, 72% were undocumented migrants, 21% were living in Suriname and 48% had baseline CD4 cell counts <200 cells/mm3. After one year, 34% were lost to follow-up, 54% received treatment, 34% had controlled viremia and 6% died. We observed a disappointing HIV cascade, like that of Suriname, requiring to develop a coordinated healthcare offer on both sides of the border. Targeted efforts through a bi-national collaboration are needed to address the specific issues of cross-border patients to reach the 90*3 UNAIDS’s diagnosis, link to care and treatment targets and better control the local epidemic
ISSN: 0954-0121

inserm-01476267
http://www.hal.inserm.fr/inserm-01476267
http://www.hal.inserm.fr/inserm-01476267/document
http://www.hal.inserm.fr/inserm-01476267/file/2017%20Jaries%20-%20Population%20movements%20and%20the%20HIV%20cascade-1.pdf
DOI : 10.1080/09540121.2017.1291899