Effets de la salinité sur la toxicité sous-létale de l'atrazine pour des larves de choquemort, Fundulus heteroclitus

Dans leurs aires de ponte des marais côtiers, les jeunes stades de poissons marins peuvent être exposés simultanément à des fluctuations de salinité et à l' atrazine, un herbicide largement utilisé pouvant perturber les mécanismes d'osmorégulation. Les effets de la salinité sur la toxicité sous-létale de l'atrazine ont été étudiés chez les larves du choquemort (Fundulus heteroclitus). À l'éclosion, les larves étaient exposées à différentes concentrations d' atrazine (0, 5, 50 et 500 Jlg/L) dans trois conditions de salinité (3 , 15 et 35 PSU (unités pratiques de salinité, ou en anglais « rractical S.alinity Units »)) pendant 96 heures, avec renouvellement des solutions d'exposition aux 24 heures. Après une exposition de 96 heures, le contenu en eau des larves (ajusté pour la masse sèche) a été mesuré comme indicateur de l' osmorégulation tandis que la masse sèche (ajustée pour la longueur) et les contenus en protéines (ajustés pour la masse sèche) et en lipides ont été mesurés comme indicateur de condition. Après une exposition de 24 heures, les concentrations en cortisol ont été mesurées comme indicateurs de stress. En absence d' atrazine, la salinité affectait seulement le contenu en eau ajusté, qui était légèrement diminué à salinité 35 PSu. Des différences de toxicité de l' atrazine selon la salinité pouvaient être notées. En milieu presque isosmotique (salinité 15 PSU), l' atrazine diminuait le contenu en eau des larves à 2: 5 Jlg/L, ce qui indiquait des problèmes d' osmorégulation, tandis que la condition et les concentrations de cortisol des larves n'étaient pas affectées. En milieu hyperosmotique (salinité 35 PSU), l' atrazine causait une diminution du contenu en eau plus marquée que celle observée en absence d'atrazine. La condition des larves était également affectée par 500 Jlg/L d'atrazine à cette salinité, tandis que les concentrations de cortisol n' étaient pas affectées. En milieu hypoosmotique (salinité 3 PSU), le contenu en eau des larves présentait une courbe concentration réponse anormale avec une augmentation significative des contenus en eau à 5 flg/L et un retour à la normale aux plus fortes concentrations. La condition des larves était affectée par l' atrazine à 2 50 flg/L. Les concentrations de cortisol à 500 flg/L étaient significativement plus élevées que celles présentées à 5 et 50 flg/L à cette salinité. Les effets de l' atrazine sur la condition étaient donc plus prononcés à salinité 3 PSU et absents à salinité 15 PSu. Une concentration sans effet observable n' a pas été atteinte au cours de notre expérience. Des changements dans le contenu en eau et la condition des larves ont été observés à des concentrations d' atrazine réalistes d' un point de vue environnemental, soit à 5 et 50 flg/L , respectivement. L'impact de tels changements sur la survie et le développement des larves reste à déterminer. Les risques d'effets toxiques chez les jeunes stades de poissons exposés à l'atrazine dans des conditions extrêmes de salinité peuvent être sous-estimés si on se base uniquement sur des tests de toxicité réalisés dans des conditions optimales de salinité

Assessing the role of landscape connectivity in recent woodpecker range expansion in Mediterranean Europe: forest management implications

International audienceWoodpecker species have significantly expanded their ranges in the last decades of the twentieth century in Mediterranean Europe, which seems to be closely related to forest maturation following large-scale decline in traditional uses. Here we assess the explicit role of forest landscape connectivity in the colonization of the Great Spotted Woodpecker (Dendrocopos major) and the Black Woodpecker (Dryocopus martius) in Catalonia (NE Spain). For this purpose we combined data on breeding bird atlas (10 9 10 km; 1980-2000) and forest inventories (c. 1 9 1 km, 2000). Forest connectivity was measured through graph theory and habitat availability metrics (interand intra-patch connectivity) according to species median natal dispersal distances. The best regressions from a set of alternative models were selected based on AICc. Results showed that connectivity between areas of mature forests [diameter at breast height (dbh) >= 35 cm] affected Black Woodpecker colonization events. The probability of colonization of the Great Spotted Woodpecker was greater at localities near the sources of colonization in 1980 and with a high connectivity with other less developed forest patches (dbh < 35 cm). The spatial grain at which landscape connectivity was measured influenced the model performance according to the species dispersal abilities, with the species with the lower mobility (D. major) responding better to the forest connectivity patterns at finer spatial scales. Overall, it seems that both species could expand further in European Mediterranean forests in upcoming years but at slower rates if landscape connectivity according to species requirements does not continue to increase. Hence, a proactive and adaptive management should be carried out in order to preserve these species while considering the related major impacts of global change in Mediterranean Europe

Shrimp Protein Hydrolysate Modulates the Timing of Proinflammatory Macrophages in Bupivacaine-Injured Skeletal Muscles in Rats

This study was designed to determine whether marine-derived proteins other than cod could have beneficial effects on inflammation following muscle injury. Macrophage and neutrophil densities were measured from bupivacaine-injured tibialis anterior muscle of rats fed isoenergetic diets containing either shrimp hydrolysate (Shr), casein hydrolysate (CaH), or whole casein (Ca). In this study, Shr reduced ED1+-macrophages at day 2 (p=0.013), day 5 (p=0.006), and day 14 after injury (p=0.038) compared with Ca, indicating faster resolution of inflammation in Shr. Except for day 2 after injury where Shr led to lower ED1+-macrophages compared with CaH (p=0.006), both Shr and CaH responded similarly at days 5, 14, and 28 after injury. This findings suggest that beneficial effects of Shr on ED1+-cells might be related to generation of anti-inflammatory peptides through the hydrolysis process, in addition to its high content of anti-inflammatory amino acids. However, while increasing myofiber cross-sectional area in noninjured muscles compared with both Ca and CaH, Shr failed to have a positive effect in corresponding injured muscles. These data indicate that shrimp hydrolysate can facilitate resolution of inflammation after muscle injury mainly through modulating proinflammatory macrophage accumulation but have less effect on optimal recovery in terms of muscle mass and fiber size

ILC Reference Design Report Volume 1 - Executive Summary

The International Linear Collider (ILC) is a 200-500 GeV center-of-mass high-luminosity linear electron-positron collider, based on 1.3 GHz superconducting radio-frequency (SCRF) accelerating cavities. The ILC has a total footprint of about 31 km and is designed for a peak luminosity of 2x10^34 cm^-2s^-1. This report is the Executive Summary (Volume I) of the four volume Reference Design Report. It gives an overview of the physics at the ILC, the accelerator design and value estimate, the detector concepts, and the next steps towards project realization.The International Linear Collider (ILC) is a 200-500 GeV center-of-mass high-luminosity linear electron-positron collider, based on 1.3 GHz superconducting radio-frequency (SCRF) accelerating cavities. The ILC has a total footprint of about 31 km and is designed for a peak luminosity of 2x10^34 cm^-2s^-1. This report is the Executive Summary (Volume I) of the four volume Reference Design Report. It gives an overview of the physics at the ILC, the accelerator design and value estimate, the detector concepts, and the next steps towards project realization

ILC Reference Design Report Volume 4 - Detectors

This report, Volume IV of the International Linear Collider Reference Design Report, describes the detectors which will record and measure the charged and neutral particles produced in the ILC's high energy e+e- collisions. The physics of the ILC, and the environment of the machine-detector interface, pose new challenges for detector design. Several conceptual designs for the detector promise the needed performance, and ongoing detector R&D is addressing the outstanding technological issues. Two such detectors, operating in push-pull mode, perfectly instrument the ILC interaction region, and access the full potential of ILC physics.This report, Volume IV of the International Linear Collider Reference Design Report, describes the detectors which will record and measure the charged and neutral particles produced in the ILC's high energy e+e- collisions. The physics of the ILC, and the environment of the machine-detector interface, pose new challenges for detector design. Several conceptual designs for the detector promise the needed performance, and ongoing detector R&D is addressing the outstanding technological issues. Two such detectors, operating in push-pull mode, perfectly instrument the ILC interaction region, and access the full potential of ILC physics