Effects of fluoride on primary cultured haemocytes from the marine gastropod Haliotis tuberculata

International audienceAs a consequence of human's activities, fluoride concentration in many aquatic ecosystems is significantly increasing. Nevertheless, little is known about fluoride toxicity to aquatic life. In this study the effect of exposure to different concentrations of sodium fluoride (2, 10, 50, 250 and 1,250 μg mL −1) during 24 h on primary cultured haemocytes of the gastropod Haliotis tuberculata was realized. Results indicate no significant effect of NaF on cell viability, Lysosomal membrane stability, phagocytosis and ROS production at concentrations of 2, 10, 50 and 250 μg mL −1. Nevertheless, lysosomal membrane alterations, a decrease of phagocytosis and morphological changes of H. tuberculata haemocytes were observed at concentration of 1,250 µg mL −1 NaF suggesting a potential impact of NaF at high concentration in the environment

The impact of deregulation and re-regulation on bank efficiency: evidence from Asia

Following the 1997 crisis, banking sector reforms in Asia have been characterised by the emphasis on prudential regulation, associated with increased financial liberalisation. Using a panel data set of commercial banks from eight major Asian economies over the period 2001-2010, this study explores how the coexistence of liberalisation and prudential regulation affects banks’ cost characteristics. Given the presence of heterogeneity of technologies across countries, we use a stochastic frontier approach followed by the estimation of a deterministic meta-frontier to provide ‘true’ estimates of bank cost efficiency measures. Our results show that the liberalization of bank interest rates and the increase in foreign banks' presence have had a positive and significant impact on technological progress and cost efficiency. On the other hand, we find that prudential regulation might adversely affect bank cost performance. When designing an optimal regulatory framework, policy makers should combine policies which aim to foster financial stability without hindering financial intermediation

Suppression of Phospholipase Dγs Confers Increased Aluminum Resistance in Arabidopsis thaliana

Aluminum (Al) toxicity is the major stress in acidic soil that comprises about 50% of the world's arable land. The complex molecular mechanisms of Al toxicity have yet to be fully determined. As a barrier to Al entrance, plant cell membranes play essential roles in plant interaction with Al, and lipid composition and membrane integrity change significantly under Al stress. Here, we show that phospholipase Dγs (PLDγs) are induced by Al stress and contribute to Al-induced membrane lipid alterations. RNAi suppression of PLDγ resulted in a decrease in both PLDγ1 and PLDγ2 expression and an increase in Al resistance. Genetic disruption of PLDγ1 also led to an increased tolerance to Al while knockout of PLDγ2 did not. Both RNAi-suppressed and pldγ1-1 mutants displayed better root growth than wild-type under Al stress conditions, and PLDγ1-deficient plants had less accumulation of callose, less oxidative damage, and less lipid peroxidation compared to wild-type plants. Most phospholipids and glycolipids were altered in response to Al treatment of wild-type plants, whereas fewer changes in lipids occurred in response to Al stress in PLDγ mutant lines. Our results suggest that PLDγs play a role in membrane lipid modulation under Al stress and that high activities of PLDγs negatively modulate plant tolerance to Al

Impacts des rejets industriels sur les eaux de la région de Berrahal (Nord Est Algérien)

L’important développement industriel dans la région de Berrahal (Nord-Est de l’Algérie) s’est traduit par un accroissement des rejets concentrés en métaux lourds considérés comme toxiques pour la faune et la flore, induisant une dégradation de l’environnement et de la qualité des eaux des aquifères. L’analyse statistique des données acquises a permis d’élaborer le schéma de transfert des polluants et d’identifier les  principaux facteurs responsables de l’acquisition du contenu physico-chimique des eaux. Les résultats obtenus montrent que les milieux récepteurs (les habitants, le lac Fetzara et la nappe phréatique) seront touchés par les différents rejets de la zone industrielle. L’infiltration des eaux des rejets constitue par conséquent, une menace pour les populations et la faune environnante. Par ailleurs, les eaux souterraines présentent également un risque potentiel particulièrement pour l'écosystème du lac Fetzara et pour les captages d’eau (AEP, irrigation et alimentation du bétail).Mots clés : Rejets industriels - Métaux lourds - Pollution - Lac Fetzara - Berrahal.The continuous increase of industrial activities in the Berrahal region (NE of Algeria) has resulted in an increase in waste disposal rate, practically the increase of heavy metals in these wastes that are considered toxic for wildlife, inducing both environmental and groundwater pollution. The available data on soil and groundwater contamination was used to identify the different scenarios to pollution and transfer of the pollutants. The obtained results highlight that the receptor (humans, Fetzara Lake, alluvial aquifer) were linked to primary and secondary transport mechanisms. The considered exposure pathways were the inhalation of volatile substances and the direct contact with soil (ingestion and dermal contact) that could threaten both humans and wildlife, on-site or off-site. In addition, the groundwater was considered to be a potential risk pathway, especially for the ecosystem of Fetzara Lake, and for the alluvial aquifer (irrigation, drinking water).Keywords: Industrial wastes - Heavy metals – Pollution - Fetzara Lake - Berrahal

A comparative analysis of fatty acid composition of root and shoot lipids in Zea mays under copper and cadmium stress

A comparative analysis of fatty acid composition was conducted in maize ( Zea mays L.) under copper and cadmium stress. The unsaturation level (double-bond index) of phosphatidylethanolamine (PE) and digalactosyldiacylglycerol (DGDG) was increased in response to both metal treatments, whereas the phosphatidylinositol (PI), the phosphatidylcholine (PC) showed no significant changes. The Cu-treated roots showed a marked increase (about 2-fold) in the phospholipid (PL) content, while the Cd-treated roots showed a slight but insignificant increase. The steryl lipid SL/PL ratio was markedly decreased in response to Cu stress, and therefore, may indicate an activated phospholipid biosynthesis and turnover, in response to damage caused by Cu stress. The double bond indices of chloroplastic lipids: phosphatidylglycerol (PG), monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol (DGDG) and sulfoquinovosyldiacylglycerol (SQDG) revealed a similar but not identical pattern of change. The PG and MGDG contents in shoots were markedly decreased under Cu (by 53 and 48%) and Cd (by 78 and 65%) stress. The increase in the malondialdehyde (MDA) content in roots induced by both metals indicates lipid peroxidation. Generally, in the presence of Cu fatty acid composition was markedly modulated but to lesser extent under Cd stress. These results suggest that changes in the fatty acid composition under Cu and Cd stress conditions are metal-specific and may therefore result in differential metal tolerance

Formes clinico-épidémiologiques des leishmanioses cutanées en Tunisie

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