Les milieux aquatiques de la région de Trinidad (Béni, Amazonie bolivienne)

Les Llanos de Mojos (Province du Béni, Amazonie bolivienne) restent encore très peu connus, ce qui conduit à présenter une courte synthèse de la géographie physique de cette région. L'hydrologie des Llanos dépend d'une part des pluies locales abondantes d'octobre à avril, d'autre part de l'énorme apport des cours d'eau d'origine andine. Le régime du rio Mamoré à Trinidad est de type tropical, très irrégulier et sujet à de fréquentes crues éclair. Un ensemble de facteurs morphologiques, hydrologiques et anthropiques explique l'inondation, durant cinq mois environ, de superficies considérables dépassant 100 000 km2 aux plus hautes eaux. Deux types d'eau se partagent les principaux milieux aquatiques de la région : les eaux "blanches" d'origine andine, neutres, turbides, de conductivité moyenne, et les eaux "noires" d'origine locale, acides, peu chargées de matières en suspension et de faible conductivité. Les principaux milieux permanents de la région de Trinidad sont décrits, en particulier le rio Mamoré, les lacs de méandre de la forêt-galerie du Mamoré et les nombreux lacs plats orientés de la savane qui l'encadre. (Résumé d'auteur

Liste commentée des poissons de l'Amazonie bolivienne

Après une brève présentation de l'Amazonie bolivienne, des milieux prospectés, de l'effort de pêche, des travaux anciens et récents, les auteurs founissent une liste commentée des poissons rencontrés. Sur l'ensemble de l'Amazonie bolivienne 389 espèces ont été identifiées. Les différences entre les quatre grands fleuves (Béni, Madre de Dios, Mamoré, Guaporé) constituant le Haut-Madeira sont soulignées. Dans le bassin du Mamoré, intensément prospecté, 327 espèces ont été récoltées avec une forte dominance des siluriformes (45%) et des #Characoidei$ (39%). Dans ce bassin les auteurs distinguent une zone de plaine et une zone andine (au dessus de 200 m) séparée en trois sous-zones en fonction des associations ichtyques rencontrées. (Résumé d'auteur

Resource competition affects plankton community structure; evidence from trait-based modeling

Understanding the phenology of phytoplankton species is a challenge and despite a lot of theoretical work on competition for resources, this process is under-represented in deterministic models. To study the main driver of the species selection, we used a trait-based model that keeps phenotypic variability through physiological trait parameterization. Next, we validated the results by using the toxic dinoflagellate Alexandrium minutum which is a toxic species. Due to their monitoring, we show that harmful algae are ideal models for studying ecological niches and for contributing to this more global challenge. As a first step, a dimensionless model of an estuary (France) was built with water temperature and water exchanges deduced from a hydro-dynamic model. The biological parametrization takes into account the size (from pico- to microphytoplankton) and the type of assimilation. The results show that temperature, competition for nutrients and dilution are important factors regulating the community structure and Alexandrium minutum dynamics (more especially the bloom initiation and magnitude). These drivers contribute to the determination of the ecological niche of A. minutum, influence the shape of its blooms and provide potential explanations of its interannual variability. This approach makes the community structure more flexible in order to study how environmental forcings could drive its evolution

Voltage-gated sodium channels: new targets in cancer therapy?

Early detection and treatment of cancers have increased survival and improved clinical outcome. The development of metastases is often associated with a poor prognostic of survival. Finding early markers of metastasis and developing new therapies against their development is a great challenge. Since a few years, there is more evidence that ionic channels are involved in the oncogenic process. Among these, voltage-gated sodium channels expressed in non-nervous or non-muscular organs are often associated with the metastatic behaviour of different cancers. The aim of this review is to describe the current knowledge on the functional expression of voltage-gated sodium channels and their biological roles in different cancers such as prostate, breast, lung (small cells and non-small cells) and leukaemia. In the conclusion, we develop conceptual approaches to understand how such channels can be involved in the metastatic process and conclude that blockers targeted toward these channels are promising new therapeutic solutions against metastatic cancers

Data-Based System Engineering: ICDs management with SysML

International audienceSystem engineering best pratices are well described in handbooks and guidelines such as the International Council on Systems Engineering (INCOSE) handbook [1] and certification guidelines such as the ARP4754A Guidelines for Development of Civil Aircraft and Systems [2]. These clearly define the development and verification processes including system requirements, functional decomposition, and architecture design.The OMG (Object Management Group) has defined the Systems Modeling Language (SysML) standard [4] specifically to support the system engineering development processes through models. The benefits of models versus Documents-based processes has been highlighted in many papers; it allows in particular, automated verification of design consistency.Several tools such as Papyrus [6] from the Eclipse foundation support the SysML language. Even if, in practice, discrepencies still exist amoung tools, it allows, in principle to move, with limited efforts, models from one vendor to another one, removing the fear from users to be prisoners from proprietary languages. Despite these good arguments, the usage of SysML tools is not yet widely deployed for large industrial projects. One concern is the management of Interface Control Documents (ICDs) [4] that is at the center of most industries’ system engineering processes, and that is not supported in a straightforward way by SysML.This paper highlights the challenge in supporting ICDs by SysML tools, and demonstrates how these requests are supported by the SysML-based Esterel Technologies’ SCADE System® product [7]

Methods and pharmaceutical compositions for the cardioprotection

The present invention relates to methods and pharmaceutical compositions for cardioprotection of subjects who experienced a myocardial infarction. In particular, the present invention relates to a ligand of the sonic hedgehog signaling pathway for use in the cardioprotection of a subject who experienced a myocardial infarction

Voltage-gated sodium channels potentiate the invasive capacities of human non-small-cell lung cancer cell lines.

Ionic channel activity is involved in fundamental cellular behaviour and participates in cancerous features such as proliferation, migration and invasion which in turn contribute to the metastatic process. In this study, we investigated the expression and role of voltage-gated sodium channels in non-small-cell lung cancer cell lines. Functional voltage-gated sodium channels expression was investigated in normal and non-small-cell lung cancer cell lines. The measurement, in patch-clamp conditions, of tetrodotoxin-inhibitable sodium currents indicated that the strongly metastatic cancerous cell lines H23, H460 and Calu-1 possess functional sodium channels while normal and weakly metastatic cell lines do not. While all the cell lines expressed mRNA for numerous sodium channel isoforms, only H23, H460 and Calu-1 cells had a 250 kDa protein corresponding to the functional channel. The other cell lines also had another protein of 230 kDa which is not addressed to the membrane and might act as a dominant negative isoform to prevent channel activation. At the membrane potential of these cells, channels are partially open. This leads to a continuous entry of sodium, disrupting sodium homeostasis and down-stream signaling pathways. Inhibition of the channels by tetrodotoxin was responsible for a 40-50% reduction of in vitro invasion. These experiments suggest that the functional expression of voltage-gated sodium channels might be an integral component of the metastatic process in non-small-cell lung cancer cells probably through its involvement in the regulation of intracellular sodium homeostasis. These channels could serve both as novel markers of the metastatic phenotype and as potential new therapeutic targets