Cholinesterase activity and histopatological changes in the Mediterranean crab, Carcinus maenas, exposed to environmental contaminants

Marine environments are continuously being threatened by a large number of pollutants including heavy metals and organophosphorous pesticides from anthropogenic sources. These compounds can cause a serious environmental problem. The present study aimed: (1) to measure sensitivity of acetylcholinesterase (AChE) activity to in vivo exposure to the organophosphorous chlorpyriphos-ethyl (CPF) and to the heavy metals cadmium (Cd) and copper (Cu) and (2) to use the histopathological lesions as tissue biomarkers for biomonitoring of different contaminations. The results clearly showed that the AChE activity in different tissues (digestive gland, muscle and eyes) of Carcinus maenas was relatively sensitive to the concentrations of CPF and tended to have different patterns in response to Cd, Cu and Cu+Cd mixture exposure. The transfer of treated crabs to the clean sea water allowed to recover totally or partially the lost activity depending on selected tissues and contaminant exposure (metals or organophosphorous compounds). Histopathological biomarkers in C. maenas exposed to different contaminants showed the presence of different lesions which altered the digestive gland after 7 days of contamination

Étude de l’effet du cadmium et du benzo[a]pyrène sur des enzymes de phase I et phase II de biotransformation chez le polychète Nereisdiversicolor

Le présent travail reporte l’effet du cadmium (Cd), du benzo[a]pyrène (B[a]P) ainsi que leur mélange (Cd/B[a]P), à 1 µM, sur les activités d’enzymes impliqués dans la phase I et la phase II de biotransformation chez le polychète Nereis diversicolor en fonction du temps (après 12, 24, 36 et 48 h).L’effet d’une contamination aiguë par du cadmium à une dose de 1 µM après 12, 24 et 36 h montre une inhibition de l’activité NADPH cytochrome C réductase chez les individus contaminés comparés à leurs témoins relatifs, alors que le seul effet du cadmium sur l’activité glutathion-S-transférase n’est enregistré qu’après 36 h d’exposition. Quant au benzo[a]pyrène, les résultats montrent une augmentation significative de l’activité NADPH cytochrome C réductase après 12, 24 et 36 h d’exposition, alors que pour l’activité glutathion-S‑transférase, la variation significative entre les animaux témoins et traités n’est enregistrée qu’à 36 h d’exposition. Le mélange (Cd/B[a]P) inhibe l’activité NADPH cytochrome C réductase chez les individus traités par comparaison aux témoins relatifs et montre un effet inducteur sur l’activité GST sauf après 36 h d’exposition. Ces résultats montrent ainsi les interactions entre les polluants ainsi que leurs effets sur les organismes.The acute effects of cadmium and benzo[a]pyrene, individually and as a mixture, were evaluated on the phase I and phase II biotransformation enzymes of Nereis diversicolor (Polychaeta) collected from unpolluted sites. In the acute assay (1 µM) after 12, 24, 36 and 48 h, the comparison between worms exposed to cadmium and their controls showed an inhibited activity of NADPH cytochrome C reductase after 12, 24 and 36 h. For the activity of glutathione-S-transferase (GST), however, inhibition in the presence of Cd was only noted after 36 h of exposure. Although exposure to benzo[a]pyrene resulted in a significant increase in NADPH cytochrome C reductase activity after 12, 24 and 36 h, a significant difference in glutathione-S-transferase (GST) activity between treated and control animals was only observed after 36 h. The mixture (Cd/B[a]P) seemed to inhibit the activity of NADPH cytochrome C reductase and to induce the activity of GST in individuals but only up until 36 h of exposure. These findings illustrate the interactions between pollutants and their effects on organisms

Gene Expression Rhythms in the Mussel Mytilus galloprovincialis (Lam.) across an Annual Cycle

Seasonal environmental changes may affect the physiology of Mytilus galloprovincialis (Lam.), an intertidal filter-feeder bivalve occurring commonly in Mediterranean and Atlantic coastal areas. We investigated seasonal variations in relative transcript abundance of the digestive gland and the mantle (gonads) of males and females. To identify gene expression trends – in terms of relative mRNA abundance- we used a medium-density cDNA microarray (1.7 K probes) in dual-color competitive hybridization analyses. Hierarchical clustering of digestive gland microarray data showed two main branches, distinguishing profiles associated with the “hot” months (May–August) from the other months. Genes involved in chitin metabolism, associated with mussel nutrition and digestion showed higher mRNA levels during summer. Moreover, we found different gene transcriptomic patterns in the digestive glands of males when compared to females, during the four stages of mussel gonadal development. Microarray data from gonadal transcripts also displayed clear patterns during the different developmental phases respect to the resting period (stage I) with peak relative mRNA abundance at the ripe phase (stage III) for both sexes. These data showed a clear temporal pattern in transcriptomic profiles of mussels sampled over an annual cycle. Physiological response to thermal variation, food availability, and reproductive status across months may contribute to variation in relative mRNA abundance

Metallothionein induction by Cu, Cd and Hg in liver: assessment by RP-HPLC with fluorescent detection and spectrophotometry

International audienc

Impact of heavy metal contamination on oxidative stress of Eisenia andrei and bacterial community structure in Tunisian mine soil

International audienceThe aims of this work were firstly to study the effect of heavy metal-polluted soils from Tunisian mine on earth-worm biochemical biomarkers and on bacterial communities and therefore to analyze the interaction between earth worms and bacterial communities in these contaminated soils. For this purpose, we had introduced earthworm Eisenia andrei in six soils: one from mine spoils and five from agricultural soils, establishing a gradient of contamination. The response of worms to the presence of heavy metal was analyzed at the biochemical and transcriptional levels. In a second time, the impact of worm on bacterial community structure was investigated using automated ribosomal intergenic spacer analysis (ARISA) fingerprinting. An impact of heavy metal-contaminated soils on the oxidative status of E. andrei was observed, but this effect was dependent of the level of heavy metal contamination. Moreover, our results demonstrate that the introduction of earthworms E. andrei has an impact on bacterial community; however, the major change was observed in the less contaminated site. Furthermore, a significant correlation between earthworm oxidative status biomarkers and bacterial community structure was observed, mainly in the mine spoils. Therefore, we contribute to a better understanding of the relationships between epigenic earthworms and bacterial communities in heavy metal-contaminated soils

Effects of cadmium and copper on pollen germination and fruit set in pea (Pisum sativum L.)

In this work, pea (Pisum sativum) plants exposed to increasing cadmium and copper concentrations were tested for heavy metals accumulation in flowers and for '. in vivo' pollen germination. Based on the Cd and Cu accumulation amounts in the flowers, an evaluation of the same metals effects on '. in vitro' pollen germination was achieved. Moreover, the effects of both metals on fruits number and weight and on seed set and yield at individual plant level were examined. While cadmium concentrations did not affect '. in vivo' pollen germination, only higher copper concentrations rendered a significant reduction. This is in contrast with the clear negative effect on pollen germination in vitro and might be explained by the different dynamic and bioavailability of both metals. A clear effect of Cd and Cu was observed on two important yield components ie, fruit weight and seed set. Although results obtained herein cannot give a clear cut relationship between the effect of Ca and Cu on reproductive development and its consequences on yields, they represent emerging results on the potential consequences of metals contamination on reproductive development in plants.The work was partially supported by funds from the Tunisian Ministry of Higher Education, Scientific Research and Technology, and by the Research Unit “Biochemistry and Ecotoxicology”. Financial support for this work was also provided by the Spanish project grants CICYT AGL2006-13529-C02-00/AGR and by the cooperation grant AECI A/4868/06.Peer Reviewe

Assessment of the health status of Donax trunculus from the Gulf of Tunis using integrative biomarker indices

International audienceFor a few years, the littoral of the Gulf of Tunis has been subjected to agricultural activities, industrial, urban and tourist development and consequently submitted to the impact of many chemical and physical stressors. Sub-individual responses (biochemical biomarkers) in bivalves can be used as an early warning system for ecotoxicological risk assessment. However, the influence of many confounding factors such as ecological (e.g. temperature and salinity) or physiological (e.g. reproductive and nutritive status) parameters on biomarker responses must be taken carefully into account. The aim of the present study was to integrate into indices (Integrated Biomarker Response: IBR and Health Status Index: HSI) individual responses of biochemical biomarkers (acetylcholinesterase, catalase, glutathione-S-transferase, thiobarbituric acid reactive substance levels, lactate dehydrogenase and metallothionein-like proteins) and energy reserves (glycogen, lipid levels and total protein concentrations) at sub-individual level, and condition index at individual level in Donax trunculus originating from 4 sites contrasted by their level of contamination in the Gulf of Tunis. Integrated biomarkers indices have been revealed to be efficient and easy tools for environmental managers. Responses of IBR and HSI were compared and their strengths and weaknesses discussed. Results showed that HSI could be an easy tool for risk management whereas IBR results were more informative with regard to the temporal contribution of each biomarker considered in the battery used in the present work In bivalves from the reference Sidi Jehmi site, the contribution of energy reserves and the condition index reflecting a good general health status clearly influenced the temporal variations of IBR whereas in bivalves from the multi-contaminated Rades Meliane site, temporal variations of IBR were induced mainly by the responses of pollution biomarkers. Previous investigations concerning other level of biological organization (population) are in accordance with the present data (Tlili et al., 2010, 2011)

Cholinesterase activity as biomarker of neurotoxicity: utility in the assessment of aquatic environment contamination * Actividade da colinesterase como biomarcador de neurotoxicidade: avaliação da contaminação em ambientes aquáticos ** ** Portuguese Titl

AbstrAct Cholinesterase can take place in aquatic organisms under a series of environmental adverse conditions. The study of cholinesterases in these organisms can give important information about their physiological status and about environmental health. However, it is very important to know how the environmental factors such as fluctuation of physicochemical parameters associated to the presence of pollutants might affect these cholinesterase activities. We studied the response of cholinesterase activity in the caged cockle Cerastoderma glaucum. In addition, we evaluated the potential uses of cholinesterase activity in the common sole, which inhabit the Tunisian coast, subjected to different stress conditions, such as the exposure to different contaminants. This review summarizes the data obtained in some studies carried out in organisms from the Tunisian aquatic environment. Keyword