Variation in Demography and Life-History Strategies Across the Range of a Declining Mountain Bird Species

Species- and population-specific responses to their environment may depend to a large extent on the spatial variation in life-history traits and in demographic processes of local population dynamics. Yet, those parameters and their variability remain largely unknown for many cold-adapted species, which are exposed to particularly rapid rates of environmental change. Here, we compared the demographic traits and dynamics for an emblematic bird species of European mountain ecosystems, the ring ouzel (Turdus torquatus). Using integrated population models fitted in a Bayesian framework, we estimated the survival probability, productivity and immigration of two populations from the Western European Alps, in France (over 11 years) and Switzerland (over 6 years). Juvenile apparent survival was lower and immigration rate higher in the Swiss compared to the French population, with the temporal variation in population growth rate driven by different demographic processes. Yet, when compared to populations in the northwestern part of the range, in Scotland, these two Alpine populations both showed a much lower productivity and higher adult survival, indicating a slower life-history strategy. Our results suggest that demographic characteristics can substantially vary across the discontinuous range of this passerine species, essentially due to contrasted, possibly locally evolved life-history strategies. This study therefore raises the question of whether flexibility in life-history traits is widespread among boreo-alpine species and if it might provide adaptive potential for coping with current environmental change

Cancer Cell Expression of Autotaxin Controls Bone Metastasis Formation in Mouse through Lysophosphatidic Acid-Dependent Activation of Osteoclasts

Bone metastases are highly frequent complications of breast cancers. Current bone metastasis treatments using powerful anti-resorptive agents are only palliative indicating that factors independent of bone resorption control bone metastasis progression. Autotaxin (ATX/NPP2) is a secreted protein with both oncogenic and pro-metastatic properties. Through its lysosphospholipase D (lysoPLD) activity, ATX controls the level of lysophosphatidic acid (LPA) in the blood. Platelet-derived LPA promotes the progression of osteolytic bone metastases of breast cancer cells. We asked whether ATX was involved in the bone metastasis process. We characterized the role of ATX in osteolytic bone metastasis formation by using genetically modified breast cancer cells exploited on different osteolytic bone metastasis mouse models.Intravenous injection of human breast cancer MDA-B02 cells with forced expression of ATX (MDA-B02/ATX) to immunodeficiency BALB/C nude mice enhanced osteolytic bone metastasis formation, as judged by increased bone loss, tumor burden, and a higher number of active osteoclasts at the metastatic site. Mouse breast cancer 4T1 cells induced the formation of osteolytic bone metastases after intracardiac injection in immunocompetent BALB/C mice. These cells expressed active ATX and silencing ATX expression inhibited the extent of osteolytic bone lesions and decreased the number of active osteoclasts at the bone metastatic site. In vitro, osteoclast differentiation was enhanced in presence of MDA-B02/ATX cell conditioned media or recombinant autotaxin that was blocked by the autotaxin inhibitor vpc8a202. In vitro, addition of LPA to active charcoal-treated serum restored the capacity of the serum to support RANK-L/MCSF-induced osteoclastogenesis.Expression of autotaxin by cancer cells controls osteolytic bone metastasis formation. This work demonstrates a new role for LPA as a factor that stimulates directly cancer growth and metastasis, and osteoclast differentiation. Therefore, targeting the autotaxin/LPA track emerges as a potential new therapeutic approach to improve the outcome of patients with bone metastases

Shark Attacks in Dakar and the Cap Vert Peninsula, Senegal: Low Incidence despite High Occurrence of Potentially Dangerous Species

The International Shark Attack File mentions only four unprovoked shark attacks on the coast of West Africa during the period 1828–2004, an area where high concentrations of sharks and 17 species potentially dangerous to man have been observed. To investigate if the frequency of shark attacks could be really low and not just under-reported and whether there are potentially sharks that might attack in the area, a study was carried out in Dakar and the Cap Vert peninsula, Senegal. and 3 with unidentified sharks.These findings suggest that the frequency of shark attacks on the coast of West Africa is underestimated. However, they also indicate that the risk is very low despite the abundance of sharks. In Dakar area, most encounters along the coastline with potentially dangerous species do not result in an attack. Compared to other causes of water related deaths, the incidence of shark attack appears negligible, at least one thousand fold lower

A Mouse Model of Acrodermatitis Enteropathica: Loss of Intestine Zinc Transporter ZIP4 (Slc39a4) Disrupts the Stem Cell Niche and Intestine Integrity

Loss-of-function of the zinc transporter ZIP4 in the mouse intestine mimics the lethal human disease acrodermatitis enteropathica. This is a rare disease in humans that is not well understood. Our studies demonstrate the paramount importance of ZIP4 in the intestine in this disease and reveal that a root cause of lethality is disruption of the intestine stem cell niche and impaired function of the small intestine. This, in turn, leads to dramatic weight loss and death unless treated with exogenous zinc

The vertigo in the margins in the works of Salman Rushdie. Metaphoric and metonymic strategies

La figure du migrant est centrale dans l’œuvre de Salman Rushdie. Noyau d’un dispositif narratif, rhétorique, philosophique et métaphysique, elle organise une vision du monde orientée par ce qu’Edouard Glissant nomme le « nomadisme circulaire ». Dans ce monde baroque, instable et chancelant, le vacillement est maintenu par la convergence du centre et de la périphérie, qui deviennent deux formes du bord. Le transport est le nom que le grec donne à la métaphore : chez Salman Rushdie, c’est aussi le migrant. Figure de rhétorique, la métaphore relève d’un mode fondé sur la substitution et la rupture, d’après David Lodge, avec Jakobson. Inséparable de la métonymie, dont le mode est associé à la combinaison et la contiguïté, elle donne forme verbale et énergie à la puissance évocatrice et imaginatrice qui se manifeste dans les romans de Salman Rushdie. Cette énergie se fait véhicule d’un conatus centrifuge qui attire l’écriture vers les marges. Le bord s’inscrit dans la dialectique de la continuité et de la discontinuité en tant qu’il est commencement et fin. Il s’incarne dans le corps, dans divers lieux métaphoriques et poétiques, et dans des personnages appartenant tous à un entre-deux, à une réalité hybride qui favorise le basculement et le désordre. Cette thèse analysera dans quelle mesure les avatars du bord géographique, rhétorique et sémantique font prospérer une écriture génératrice d’une prolifération de sens et d’une poétique au cœur de laquelle la recherche de la « métaphore vive » [chère à Paul Ricoeur] participe d’un vertige des marges].The figure of the migrant is central in the work of Salman Rushdie. It is the fulcrum of a narratological, rhetorical, philosophical and metaphysical compound articulating a Weltanschauung oriented by what Edouard Glissant calls « circular nomadism ». In this unstable and unpoised baroque world, oscillation is maintained thanks to the convergence of the centre and the periphery, which become two versions of the edge. Transport is the name that the Greek language gives to metaphor: for Salman Rushdie, it is also the migrant. Metaphor, a rhetorical figure, derives from a mode founded upon substitution and rupture, according to David Lodge, after Jakobson. It is inseparable from metonymy, whose mode is associated with combination and contiguity, and it gives verbal shape and energy to the conjuring and evoking power which manifests itself in Salman Rushdie’s novels. This energy becomes the vehicle of a centrifugal conatus which draws the wr! iting towards the edge. The limit inscribes itself in the dialectics of continuity and discontinuity in so far as it is the beginning and the end. It is embedded in the body, in various metaphorical and poetic places, and in characters belonging to an intermediate space, to a hybrid reality where desequilibrium and disorder are rife. This thesis will analyse to what extent the avatars of the limit, be it geographical, rhetorical or semantic, create a bedrock in which this style can prosper. Generating a proliferation of meaning and forwarded by a poetics at the heart of which is the search for the « living power of metaphoricity », as suggested by Ricœur, it participates in a vertigo in the margins

Le vertige des marges dans l'oeuvre de Salman Rushdie. Stratégies métaphoriques et métonymiques

The figure of the migrant is central in the work of Salman Rushdie. It is the fulcrum of a narratological, rhetorical, philosophical and metaphysical compound articulating a Weltanschauung oriented by what Edouard Glissant calls « circular nomadism ». In this unstable and unpoised baroque world, oscillation is maintained thanks to the convergence of the centre and the periphery, which become two versions of the edge. Transport is the name that the Greek language gives to metaphor: for Salman Rushdie, it is also the migrant. Metaphor, a rhetorical figure, derives from a mode founded upon substitution and rupture, according to David Lodge, after Jakobson. It is inseparable from metonymy, whose mode is associated with combination and contiguity, and it gives verbal shape and energy to the conjuring and evoking power which manifests itself in Salman Rushdie’s novels. This energy becomes the vehicle of a centrifugal conatus which draws the wr! iting towards the edge. The limit inscribes itself in the dialectics of continuity and discontinuity in so far as it is the beginning and the end. It is embedded in the body, in various metaphorical and poetic places, and in characters belonging to an intermediate space, to a hybrid reality where desequilibrium and disorder are rife. This thesis will analyse to what extent the avatars of the limit, be it geographical, rhetorical or semantic, create a bedrock in which this style can prosper. Generating a proliferation of meaning and forwarded by a poetics at the heart of which is the search for the « living power of metaphoricity », as suggested by Ricœur, it participates in a vertigo in the margins.La figure du migrant est centrale dans l’œuvre de Salman Rushdie. Noyau d’un dispositif narratif, rhétorique, philosophique et métaphysique, elle organise une vision du monde orientée par ce qu’Edouard Glissant nomme le « nomadisme circulaire ». Dans ce monde baroque, instable et chancelant, le vacillement est maintenu par la convergence du centre et de la périphérie, qui deviennent deux formes du bord. Le transport est le nom que le grec donne à la métaphore : chez Salman Rushdie, c’est aussi le migrant. Figure de rhétorique, la métaphore relève d’un mode fondé sur la substitution et la rupture, d’après David Lodge, avec Jakobson. Inséparable de la métonymie, dont le mode est associé à la combinaison et la contiguïté, elle donne forme verbale et énergie à la puissance évocatrice et imaginatrice qui se manifeste dans les romans de Salman Rushdie. Cette énergie se fait véhicule d’un conatus centrifuge qui attire l’écriture vers les marges. Le bord s’inscrit dans la dialectique de la continuité et de la discontinuité en tant qu’il est commencement et fin. Il s’incarne dans le corps, dans divers lieux métaphoriques et poétiques, et dans des personnages appartenant tous à un entre-deux, à une réalité hybride qui favorise le basculement et le désordre. Cette thèse analysera dans quelle mesure les avatars du bord géographique, rhétorique et sémantique font prospérer une écriture génératrice d’une prolifération de sens et d’une poétique au cœur de laquelle la recherche de la « métaphore vive » [chère à Paul Ricoeur] participe d’un vertige des marges]

[Lysophosphatidic acid: a "bioactive" phospholipid]

Lysophosphatidic acid (LPA) is a "bioactive" phospholipid able to generate growth factor-like activities in a wide variety of normal and malignant cell types. LPA is proposed to play an important role in normal physiological situations such as wound healing, vascular tone, vascular integrity, or reproduction. In parallel, LPA could also be involved in the etiology of some diseases such as atherosclerosis, cancer, or obesity. The bioactivity of LPA is mediated by the activation of specific G-protein coupled receptors (LPA1, LPA2, and LPA3) leading to the activation of a number of intracellular effectors. LPA is present in solution (bound to albumin) in various extracellular fluids (blood, ascites, aqueous humor), and is released in vitro by some cell types such as platelets, cancer cells, or adipocytes. LPA is a rather polar phospholipid, which cannot easily diffuse throughout plasma membrane, and its presence outside the cells requires soluble phospholipases (secreted phospholipase A2 and soluble lysophospholipase D/autotaxin), which synthesize LPA directly in the extracellular milieu, from precursors such as phosphatidic acid and lysophosphatidylcholine. In the future, LPA receptors, as well as the enzymes involved in LPA metabolism, will constitute promising pharmacological and transgenic targets to determine the physiopathological relevance of "bioactive" LPA in vivo

Contrôle paracrine du développement du tissu adipeux par l'autotaxine et l'acide lysophosphatidique

Dans l'obésité, l'hypertrophie adipocytaire s'accompagne souvent du recrutement de nouveaux adipocytes, ou adipogenèse. Cet événement cellulaire est sous la dépendance d'hormones et de facteurs sécrétés au sein même du tissu adipeux. Parmi les lipides produits dans le compartiment extracellulaire des adipocytes, notre groupe a montré la présence d'acide lysophosphatidique (LPA). Le LPA est un phospholipide bioactif capable de réguler plusieurs réponses cellulaires via l'activation de récepteurs membranaires spécifiques couplés aux protéines G. Nous avons montré que le LPA, via l'activation du récepteur LPA1, augmentait la prolifération des préadipocytes et inhibait l'adipogenèse. La synthèse extracellulaire de LPA est catalysée par une lysophospholipase D sécrétée par l'adipocyte : l'autotaxine (ATX). L'expression de l'ATX adipocytaire augmente au cours de l'adipogenèse ainsi que dans le tissu adipeux d'individus présentant un diabète de type 2 associé à une obésité massive. Un rôle du LPA et de l'ATX comme régulateurs paracrines de l'adipogenèse et/ou du diabète associé à l'obésité est donc envisagé