Abstract In this study, we investigated physiological changes and transcriptional responses in fo... more Abstract In this study, we investigated physiological changes and transcriptional responses in four-week-old hydroponically grown Medicago sativa seedlings exposed to (PbNO 3 ) 2 (0, 10 and 100 μM) for 2 and 7 days. Fresh weight and length were reduced in both shoots and roots after 7 days exposure. Lead accumulation was time and dose-dependent with stronger phytotoxic effects in roots than in shoots, with a relatively low amount of Pb translocated from roots to shoots. Lipid peroxidation augmented remarkably, suggesting the onset of oxidative damages, with increased glutathione reductase (GR), ascorbate peroxidase (APX) and superoxide dismutase (SOD) activities. This result was accompanied by a remarkable up-regulation of APX and SOD genes. In roots, the increase of SOD transcripts was concomitant to an enhanced SOD enzymatic activity in all Pb treatments. However, the 30-fold up-regulation occurred with a remarkable APX activity inhibition, which suggests that there might be post-transcriptional modifications able to regulate root APX. Root glutathione (GSH) and homoglutathione (hGSH) concentrations decreased in a dose dependent manner, while we could not detect the accumulation of phytochelatins (PC), albeit the related gene was up-regulated. The lack of PCs synthesis suggests a post-translational regulation of its enzymatic activity. Heat shock proteins (HSP70 and HSP17.7) were increased in alfalfa shoots, implying the triggering of cellular protection mechanism to cope with lead phytotoxicity. It is concluded that alfalfa plants mitigate the oxidative damage through induction of antioxidant enzymes, and the expression of chaperone proteins to alleviate Pb toxicity; metabolic changes that could be exploited as Pb-stress bioindicators.
International Journal of Environmental Research, 2016
This study investigated the cytochemical responses in Hediste diversicolor exposed to the environ... more This study investigated the cytochemical responses in Hediste diversicolor exposed to the environmental concentrations of cadmium (1µM Cd), copper (1µM Cu) and to their equimolar mixture for 48h. Lysosomal membrane stability (LMS), neutral lipids (NL) level, lipofuscin (LF) content and Ca2+-ATPase activity were determined as early subcellular biomarkers of toxicity. The biomarker battery pointed out a high cytoxicity on the polychaete treated with metals. Excessive induction of neutral lipids and lipofuscin accumulations were observed in polychaete treated with copper than cadmium. In addition, the highest level of neutral lipids and lipofuscin was noted in mixture treated group [Cu+Cd]. The increase of neutral lipids and lipofuscin accumulations were negatively correlated with the lysosomal membrane stability and Ca2+-ATPase activity alterations. Our study also demonstrated that the cytochemical biomarkers responses were very important to identify the cellular toxic effects of meta...
International Journal of Environmental Research, 2016
This study investigated the cytochemical responses in Hediste diversicolor exposed to the environ... more This study investigated the cytochemical responses in Hediste diversicolor exposed to the environmental concentrations of cadmium (1µM Cd), copper (1µM Cu) and to their equimolar mixture for 48h. Lysosomal membrane stability (LMS), neutral lipids (NL) level, lipofuscin (LF) content and Ca2+-ATPase activity were determined as early subcellular biomarkers of toxicity. The biomarker battery pointed out a high cytoxicity on the polychaete treated with metals. Excessive induction of neutral lipids and lipofuscin accumulations were observed in polychaete treated with copper than cadmium. In addition, the highest level of neutral lipids and lipofuscin was noted in mixture treated group [Cu+Cd]. The increase of neutral lipids and lipofuscin accumulations were negatively correlated with the lysosomal membrane stability and Ca2+-ATPase activity alterations. Our study also demonstrated that the cytochemical biomarkers responses were very important to identify the cellular toxic effects of meta...
Environmental Science and Pollution Research, 2017
The aims of this work were firstly to study the effect of heavy metal-polluted soils from Tunisia... more The aims of this work were firstly to study the effect of heavy metal-polluted soils from Tunisian mine on earthworm 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 metalcontaminated 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.
Environmental Science and Pollution Research, 2017
The aims of this work were firstly to study the effect of heavy metal-polluted soils from Tunisia... more The aims of this work were firstly to study the effect of heavy metal-polluted soils from Tunisian mine on earthworm 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 metalcontaminated 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.
To investigate the protective effect of garlic powder on cadmium-induced toxicity sea bass liver,... more To investigate the protective effect of garlic powder on cadmium-induced toxicity sea bass liver, juvenile fishes where maintained under three food diets (diet 1: normal without garlic supply, diet 2: 2% garlic powder; diet 3: 6% garlic powder). After 30 days of specific diets, each group was injected with 500 μg kg −1 of Cd. The control group was the one fed with normal diet and not injected with Cd. Liver Cd, Zn, and Se loads was assessed after 1 and 3 days of Cd injections. Moreover, antioxidant enzymes activities termed as catalase, superoxide dismutase, and glutathione peroxydase as well as their gene expression levels were monitored. Finally, metallothionein protein accumulation and its gene expression regulation (MTa) were determined. In fish fed with 2 and 6% garlic powder, the amounts of Cd, Zn, and Se significantly increase in liver tissues. Two percent garlic powder specific diet reversed the Cd-induced inhibition of catalase (CAT), superoxide dismutase (SOD), and gluthathione peroxydase (GPx) and restored the Cd-induced lipid peroxidation (MDA). The increase of liver metallothionein proteins as well as the MTa gene expression level under Cd influence was more pronounced in animals maintained for 30 days under garlic power 2% diet. Our data must be carefully considered in view of the garlic powder introduction in sea bass food composition at 2% since it is an efficient prevention against Cd-induced alterations.
To investigate the protective effect of garlic powder on cadmium-induced toxicity sea bass liver,... more To investigate the protective effect of garlic powder on cadmium-induced toxicity sea bass liver, juvenile fishes where maintained under three food diets (diet 1: normal without garlic supply, diet 2: 2% garlic powder; diet 3: 6% garlic powder). After 30 days of specific diets, each group was injected with 500 μg kg −1 of Cd. The control group was the one fed with normal diet and not injected with Cd. Liver Cd, Zn, and Se loads was assessed after 1 and 3 days of Cd injections. Moreover, antioxidant enzymes activities termed as catalase, superoxide dismutase, and glutathione peroxydase as well as their gene expression levels were monitored. Finally, metallothionein protein accumulation and its gene expression regulation (MTa) were determined. In fish fed with 2 and 6% garlic powder, the amounts of Cd, Zn, and Se significantly increase in liver tissues. Two percent garlic powder specific diet reversed the Cd-induced inhibition of catalase (CAT), superoxide dismutase (SOD), and gluthathione peroxydase (GPx) and restored the Cd-induced lipid peroxidation (MDA). The increase of liver metallothionein proteins as well as the MTa gene expression level under Cd influence was more pronounced in animals maintained for 30 days under garlic power 2% diet. Our data must be carefully considered in view of the garlic powder introduction in sea bass food composition at 2% since it is an efficient prevention against Cd-induced alterations.
• C. maenas responses to contaminants at several Tunisia littoral areas were studied. • Proteins ... more • C. maenas responses to contaminants at several Tunisia littoral areas were studied. • Proteins with significant expression differences were selected after 2-DE separation. • Crabs suffer contaminant-promoted oxidative stress and inflammation. • Altered proteins are involved in molting, innate immune response and proteolysis. • New light is shed on the toxicity mechanisms of contaminants.
• C. maenas responses to contaminants at several Tunisia littoral areas were studied. • Proteins ... more • C. maenas responses to contaminants at several Tunisia littoral areas were studied. • Proteins with significant expression differences were selected after 2-DE separation. • Crabs suffer contaminant-promoted oxidative stress and inflammation. • Altered proteins are involved in molting, innate immune response and proteolysis. • New light is shed on the toxicity mechanisms of contaminants.
This study aims to evaluate the effects of exposure to 1 µM of copper during a period of test of ... more This study aims to evaluate the effects of exposure to 1 µM of copper during a period of test of 48 h, on enzymatic and lipid peroxidation biomarkers in anterior (A), middle (M) and posterior (P) body regions of the polychaeta (Nereididae) Hediste diversicolor. The biomarkers selected in this work were the NADPH cytochrome c reductase (NADPH red) as phase I biotransformation enzyme, glutathione-S-transferase (GST) as phase II enzyme, and the oxidative stress markers using catalase activity (CAT) and malondialdehyde accumulation (MDA). The NADPH red activity was not significantly affected by copper exposure in the different body regions. Glutathione-S-transferase (GST) was significantly augmented (p< 0.05) only in the A region of Cu group compared to control group. The higher and significant CAT activity (p< 0.05) was noted in the P region of treated group paralleled by a lack of MDA production in the same region. A higher MDA content was observed in A region compared with the same body region of treated worm supporting the idea of a highest oxidant condition in this region.
This study aims to evaluate the effects of exposure to 1 µM of copper during a period of test of ... more This study aims to evaluate the effects of exposure to 1 µM of copper during a period of test of 48 h, on enzymatic and lipid peroxidation biomarkers in anterior (A), middle (M) and posterior (P) body regions of the polychaeta (Nereididae) Hediste diversicolor. The biomarkers selected in this work were the NADPH cytochrome c reductase (NADPH red) as phase I biotransformation enzyme, glutathione-S-transferase (GST) as phase II enzyme, and the oxidative stress markers using catalase activity (CAT) and malondialdehyde accumulation (MDA). The NADPH red activity was not significantly affected by copper exposure in the different body regions. Glutathione-S-transferase (GST) was significantly augmented (p< 0.05) only in the A region of Cu group compared to control group. The higher and significant CAT activity (p< 0.05) was noted in the P region of treated group paralleled by a lack of MDA production in the same region. A higher MDA content was observed in A region compared with the same body region of treated worm supporting the idea of a highest oxidant condition in this region.
A five day laboratory course in Molecular Biology for PhD students is proposed. The aim of this p... more A five day laboratory course in Molecular Biology for PhD students is proposed. The aim of this program, which can be taught by a relatively small staff of experienced scientists, was to introduce basic experimental techniques which are of general use in various fields of biology and biomedicine. These include restriction enzyme purification, restriction mapping, polymerase chain reaction, cloning and DNA sequencing.
The polychaete worm Hediste diversicolor was collected in several sites from the Tunisian coast. ... more The polychaete worm Hediste diversicolor was collected in several sites from the Tunisian coast. The aim of our study was to study several cytochemical biomarkers in this species in response to a pollution gradient caused by various discharges a long the Tunisian coast. Worms were collected from six sites: Bizerta Lagoon, Gargour, Nakta, Mahres, Skhira and from Teboulba, witch is considered a reference site. The biomarkers selected in this work were lysosomal membrane stability, lipofuscin and neutral lipid accumulations and levels of Ca 2+-ATPase activity analyzed in the intestinal cells. Chemical analyses of Cd, Cu and Zn were also carried out in sediment. The results obtained indicate significant changes in most of the parameters measured in H. diversicolor. They are consistent with the chemical analysis and that worms from Bizerta and Mahres have been submitted to high levels of pollution.
Le présent travail reporte l’effet du cadmium (Cd), du benzo[a]pyrène (B[a]P) ainsi que leur méla... more 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...
The biochemical response of Mediteranean Crab (Carcinus maenas) collected at five stations of Mon... more The biochemical response of Mediteranean Crab (Carcinus maenas) collected at five stations of Monastir Bay and from Kuriat station as control was studied using a set of complementary biomarkers. The catalase, glutathione S-transferase, lactate dehydrogenase, acetycholinesterase activities; and metallothionein and malonediladehyde levels in gills were evaluated. Results revealed differences among sites in relation to each specific biomarker. Hence, a suite of biomarkers can be used to discriminate sampling sites according to types of pollution, reflecting differing conditions of anthropogenic impact. Based on Integrated Biomarker Response, the highest values and critical biochemical alteration were observed at Khniss and Ksibat in response to urban and industrial discharges and the lowest IBR value was found at reference site. The current study has shown clearly that a biomarker-based index is usefulness tool in the monitoring Tunisian coast using C. maenas as sentinel specie. Further studies in progress to investigate the seasonal variations of IBR levels and its relationship to pollutants concentrations in the sediment, gills and digestive gland of Carcinus maenas from Monastir Bay.
The acute effects of commercial formulation of chlorpyrifos-ethyl (Dursban) and the secondary tre... more The acute effects of commercial formulation of chlorpyrifos-ethyl (Dursban) and the secondary treated industrial/urban effluent (STIUE) exposure on acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activities in hepatopancreas and gills of Mediterranean crab Carcinus maenas were investigated. After 2 d of exposure to chlorpyriphos-ethyl, the AChE activity was inhibited in both organs at concentrations of 3.12 and 7.82 μg/L, whereas the BuChE was inhibited only at higher concentration 7.82 μg/L of commercial preparation Dursban. The exposure of crabs to Dursban (3.12 μg/L) showed a significant decrement of AChE activity at 24 and 48 h, whereas the BuChE was inhibited only after 24 h and no inhibition for both enzymes was observed after 72 h. Moreover, a significant repression of AChE activity was observed in both organs of C. maenas exposed to 5% of STIUE. Our experiments indicated that the measurement of AChE activity in gills and hepatopancreas of C. maenas would be useful biomarker of organophosphorous (OP) and of neurotoxic effects of STIUE in Tunisia.
In the present study biotransformation and detoxification responses to acute exposure to the poly... more In the present study biotransformation and detoxification responses to acute exposure to the polycyclic aromatic hydrocarbons benzo[a]pyrene (B[a]P) were investigated in the liver of Sparus aurata (sea bream). Sexually immature gilthead sea bream were treated by intraperitoneal injection of B[a]P (20 mg kg(-1)) for 6, 12, 24, and 48 h. B[a]P accumulation was quantified in sea bream liver by mean of gas phase chromatography (GPC-MS) after the various exposure periods. The following biological responses were measured: (1) ethoxyresorufin-O-deethylase (EROD) activity, as a phase I biotransformation parameter; (2) liver glutathione S-transferase (GST) activity as a phase II conjugation enzyme. DNA damage was assessed over time using the single-cell gel electrophoresis comet assay. B[a]P bioaccumulation in the liver resulted in a biphasic curve with an increasing uptake up to 5.55 +/- 0.67 microg g(-1) dry weight after only 6 h exposure and 4.67 +/- 0.68 microg g(-1) dry weight after 48 h exposure. EROD activity showed a nonsymmetrical bell-shaped kinetic with a maximum at 24 h and lower but significant activities at 12 and 48 h with respect to control animals. Hepatic GST activities were only significant after 48 h exposure. Comet assay showed an increase in liver cells DNA damage with a maximum after 48 h exposure reaching up to 12.17 % DNA in the tail.
The levels of metallothionein (MT), a biomarker of metal exposure, and of Cd and Cu, known as MT ... more The levels of metallothionein (MT), a biomarker of metal exposure, and of Cd and Cu, known as MT inducers, were investigated in Sparus aurata intraperitoneally injected with 500 lg/kg of Cu and Cd for 2 days. MT and metal concentrations (Cd and Cu) were determined in liver, gills and kidney. MT levels were significantly increased in all investigated tissues, with the highest value in liver of Cu as Cdtreated fishes (3.56-fold and 3.3-fold, respectively). Metal concentrations were statistically different between all tissues. Highest metal concentrations were in the liver. The higher metal concentrations and MT induction levels support the main role of MT in metal homeostasis and detoxification.
Abstract In this study, we investigated physiological changes and transcriptional responses in fo... more Abstract In this study, we investigated physiological changes and transcriptional responses in four-week-old hydroponically grown Medicago sativa seedlings exposed to (PbNO 3 ) 2 (0, 10 and 100 μM) for 2 and 7 days. Fresh weight and length were reduced in both shoots and roots after 7 days exposure. Lead accumulation was time and dose-dependent with stronger phytotoxic effects in roots than in shoots, with a relatively low amount of Pb translocated from roots to shoots. Lipid peroxidation augmented remarkably, suggesting the onset of oxidative damages, with increased glutathione reductase (GR), ascorbate peroxidase (APX) and superoxide dismutase (SOD) activities. This result was accompanied by a remarkable up-regulation of APX and SOD genes. In roots, the increase of SOD transcripts was concomitant to an enhanced SOD enzymatic activity in all Pb treatments. However, the 30-fold up-regulation occurred with a remarkable APX activity inhibition, which suggests that there might be post-transcriptional modifications able to regulate root APX. Root glutathione (GSH) and homoglutathione (hGSH) concentrations decreased in a dose dependent manner, while we could not detect the accumulation of phytochelatins (PC), albeit the related gene was up-regulated. The lack of PCs synthesis suggests a post-translational regulation of its enzymatic activity. Heat shock proteins (HSP70 and HSP17.7) were increased in alfalfa shoots, implying the triggering of cellular protection mechanism to cope with lead phytotoxicity. It is concluded that alfalfa plants mitigate the oxidative damage through induction of antioxidant enzymes, and the expression of chaperone proteins to alleviate Pb toxicity; metabolic changes that could be exploited as Pb-stress bioindicators.
International Journal of Environmental Research, 2016
This study investigated the cytochemical responses in Hediste diversicolor exposed to the environ... more This study investigated the cytochemical responses in Hediste diversicolor exposed to the environmental concentrations of cadmium (1µM Cd), copper (1µM Cu) and to their equimolar mixture for 48h. Lysosomal membrane stability (LMS), neutral lipids (NL) level, lipofuscin (LF) content and Ca2+-ATPase activity were determined as early subcellular biomarkers of toxicity. The biomarker battery pointed out a high cytoxicity on the polychaete treated with metals. Excessive induction of neutral lipids and lipofuscin accumulations were observed in polychaete treated with copper than cadmium. In addition, the highest level of neutral lipids and lipofuscin was noted in mixture treated group [Cu+Cd]. The increase of neutral lipids and lipofuscin accumulations were negatively correlated with the lysosomal membrane stability and Ca2+-ATPase activity alterations. Our study also demonstrated that the cytochemical biomarkers responses were very important to identify the cellular toxic effects of meta...
International Journal of Environmental Research, 2016
This study investigated the cytochemical responses in Hediste diversicolor exposed to the environ... more This study investigated the cytochemical responses in Hediste diversicolor exposed to the environmental concentrations of cadmium (1µM Cd), copper (1µM Cu) and to their equimolar mixture for 48h. Lysosomal membrane stability (LMS), neutral lipids (NL) level, lipofuscin (LF) content and Ca2+-ATPase activity were determined as early subcellular biomarkers of toxicity. The biomarker battery pointed out a high cytoxicity on the polychaete treated with metals. Excessive induction of neutral lipids and lipofuscin accumulations were observed in polychaete treated with copper than cadmium. In addition, the highest level of neutral lipids and lipofuscin was noted in mixture treated group [Cu+Cd]. The increase of neutral lipids and lipofuscin accumulations were negatively correlated with the lysosomal membrane stability and Ca2+-ATPase activity alterations. Our study also demonstrated that the cytochemical biomarkers responses were very important to identify the cellular toxic effects of meta...
Environmental Science and Pollution Research, 2017
The aims of this work were firstly to study the effect of heavy metal-polluted soils from Tunisia... more The aims of this work were firstly to study the effect of heavy metal-polluted soils from Tunisian mine on earthworm 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 metalcontaminated 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.
Environmental Science and Pollution Research, 2017
The aims of this work were firstly to study the effect of heavy metal-polluted soils from Tunisia... more The aims of this work were firstly to study the effect of heavy metal-polluted soils from Tunisian mine on earthworm 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 metalcontaminated 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.
To investigate the protective effect of garlic powder on cadmium-induced toxicity sea bass liver,... more To investigate the protective effect of garlic powder on cadmium-induced toxicity sea bass liver, juvenile fishes where maintained under three food diets (diet 1: normal without garlic supply, diet 2: 2% garlic powder; diet 3: 6% garlic powder). After 30 days of specific diets, each group was injected with 500 μg kg −1 of Cd. The control group was the one fed with normal diet and not injected with Cd. Liver Cd, Zn, and Se loads was assessed after 1 and 3 days of Cd injections. Moreover, antioxidant enzymes activities termed as catalase, superoxide dismutase, and glutathione peroxydase as well as their gene expression levels were monitored. Finally, metallothionein protein accumulation and its gene expression regulation (MTa) were determined. In fish fed with 2 and 6% garlic powder, the amounts of Cd, Zn, and Se significantly increase in liver tissues. Two percent garlic powder specific diet reversed the Cd-induced inhibition of catalase (CAT), superoxide dismutase (SOD), and gluthathione peroxydase (GPx) and restored the Cd-induced lipid peroxidation (MDA). The increase of liver metallothionein proteins as well as the MTa gene expression level under Cd influence was more pronounced in animals maintained for 30 days under garlic power 2% diet. Our data must be carefully considered in view of the garlic powder introduction in sea bass food composition at 2% since it is an efficient prevention against Cd-induced alterations.
To investigate the protective effect of garlic powder on cadmium-induced toxicity sea bass liver,... more To investigate the protective effect of garlic powder on cadmium-induced toxicity sea bass liver, juvenile fishes where maintained under three food diets (diet 1: normal without garlic supply, diet 2: 2% garlic powder; diet 3: 6% garlic powder). After 30 days of specific diets, each group was injected with 500 μg kg −1 of Cd. The control group was the one fed with normal diet and not injected with Cd. Liver Cd, Zn, and Se loads was assessed after 1 and 3 days of Cd injections. Moreover, antioxidant enzymes activities termed as catalase, superoxide dismutase, and glutathione peroxydase as well as their gene expression levels were monitored. Finally, metallothionein protein accumulation and its gene expression regulation (MTa) were determined. In fish fed with 2 and 6% garlic powder, the amounts of Cd, Zn, and Se significantly increase in liver tissues. Two percent garlic powder specific diet reversed the Cd-induced inhibition of catalase (CAT), superoxide dismutase (SOD), and gluthathione peroxydase (GPx) and restored the Cd-induced lipid peroxidation (MDA). The increase of liver metallothionein proteins as well as the MTa gene expression level under Cd influence was more pronounced in animals maintained for 30 days under garlic power 2% diet. Our data must be carefully considered in view of the garlic powder introduction in sea bass food composition at 2% since it is an efficient prevention against Cd-induced alterations.
• C. maenas responses to contaminants at several Tunisia littoral areas were studied. • Proteins ... more • C. maenas responses to contaminants at several Tunisia littoral areas were studied. • Proteins with significant expression differences were selected after 2-DE separation. • Crabs suffer contaminant-promoted oxidative stress and inflammation. • Altered proteins are involved in molting, innate immune response and proteolysis. • New light is shed on the toxicity mechanisms of contaminants.
• C. maenas responses to contaminants at several Tunisia littoral areas were studied. • Proteins ... more • C. maenas responses to contaminants at several Tunisia littoral areas were studied. • Proteins with significant expression differences were selected after 2-DE separation. • Crabs suffer contaminant-promoted oxidative stress and inflammation. • Altered proteins are involved in molting, innate immune response and proteolysis. • New light is shed on the toxicity mechanisms of contaminants.
This study aims to evaluate the effects of exposure to 1 µM of copper during a period of test of ... more This study aims to evaluate the effects of exposure to 1 µM of copper during a period of test of 48 h, on enzymatic and lipid peroxidation biomarkers in anterior (A), middle (M) and posterior (P) body regions of the polychaeta (Nereididae) Hediste diversicolor. The biomarkers selected in this work were the NADPH cytochrome c reductase (NADPH red) as phase I biotransformation enzyme, glutathione-S-transferase (GST) as phase II enzyme, and the oxidative stress markers using catalase activity (CAT) and malondialdehyde accumulation (MDA). The NADPH red activity was not significantly affected by copper exposure in the different body regions. Glutathione-S-transferase (GST) was significantly augmented (p< 0.05) only in the A region of Cu group compared to control group. The higher and significant CAT activity (p< 0.05) was noted in the P region of treated group paralleled by a lack of MDA production in the same region. A higher MDA content was observed in A region compared with the same body region of treated worm supporting the idea of a highest oxidant condition in this region.
This study aims to evaluate the effects of exposure to 1 µM of copper during a period of test of ... more This study aims to evaluate the effects of exposure to 1 µM of copper during a period of test of 48 h, on enzymatic and lipid peroxidation biomarkers in anterior (A), middle (M) and posterior (P) body regions of the polychaeta (Nereididae) Hediste diversicolor. The biomarkers selected in this work were the NADPH cytochrome c reductase (NADPH red) as phase I biotransformation enzyme, glutathione-S-transferase (GST) as phase II enzyme, and the oxidative stress markers using catalase activity (CAT) and malondialdehyde accumulation (MDA). The NADPH red activity was not significantly affected by copper exposure in the different body regions. Glutathione-S-transferase (GST) was significantly augmented (p< 0.05) only in the A region of Cu group compared to control group. The higher and significant CAT activity (p< 0.05) was noted in the P region of treated group paralleled by a lack of MDA production in the same region. A higher MDA content was observed in A region compared with the same body region of treated worm supporting the idea of a highest oxidant condition in this region.
A five day laboratory course in Molecular Biology for PhD students is proposed. The aim of this p... more A five day laboratory course in Molecular Biology for PhD students is proposed. The aim of this program, which can be taught by a relatively small staff of experienced scientists, was to introduce basic experimental techniques which are of general use in various fields of biology and biomedicine. These include restriction enzyme purification, restriction mapping, polymerase chain reaction, cloning and DNA sequencing.
The polychaete worm Hediste diversicolor was collected in several sites from the Tunisian coast. ... more The polychaete worm Hediste diversicolor was collected in several sites from the Tunisian coast. The aim of our study was to study several cytochemical biomarkers in this species in response to a pollution gradient caused by various discharges a long the Tunisian coast. Worms were collected from six sites: Bizerta Lagoon, Gargour, Nakta, Mahres, Skhira and from Teboulba, witch is considered a reference site. The biomarkers selected in this work were lysosomal membrane stability, lipofuscin and neutral lipid accumulations and levels of Ca 2+-ATPase activity analyzed in the intestinal cells. Chemical analyses of Cd, Cu and Zn were also carried out in sediment. The results obtained indicate significant changes in most of the parameters measured in H. diversicolor. They are consistent with the chemical analysis and that worms from Bizerta and Mahres have been submitted to high levels of pollution.
Le présent travail reporte l’effet du cadmium (Cd), du benzo[a]pyrène (B[a]P) ainsi que leur méla... more 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...
The biochemical response of Mediteranean Crab (Carcinus maenas) collected at five stations of Mon... more The biochemical response of Mediteranean Crab (Carcinus maenas) collected at five stations of Monastir Bay and from Kuriat station as control was studied using a set of complementary biomarkers. The catalase, glutathione S-transferase, lactate dehydrogenase, acetycholinesterase activities; and metallothionein and malonediladehyde levels in gills were evaluated. Results revealed differences among sites in relation to each specific biomarker. Hence, a suite of biomarkers can be used to discriminate sampling sites according to types of pollution, reflecting differing conditions of anthropogenic impact. Based on Integrated Biomarker Response, the highest values and critical biochemical alteration were observed at Khniss and Ksibat in response to urban and industrial discharges and the lowest IBR value was found at reference site. The current study has shown clearly that a biomarker-based index is usefulness tool in the monitoring Tunisian coast using C. maenas as sentinel specie. Further studies in progress to investigate the seasonal variations of IBR levels and its relationship to pollutants concentrations in the sediment, gills and digestive gland of Carcinus maenas from Monastir Bay.
The acute effects of commercial formulation of chlorpyrifos-ethyl (Dursban) and the secondary tre... more The acute effects of commercial formulation of chlorpyrifos-ethyl (Dursban) and the secondary treated industrial/urban effluent (STIUE) exposure on acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activities in hepatopancreas and gills of Mediterranean crab Carcinus maenas were investigated. After 2 d of exposure to chlorpyriphos-ethyl, the AChE activity was inhibited in both organs at concentrations of 3.12 and 7.82 μg/L, whereas the BuChE was inhibited only at higher concentration 7.82 μg/L of commercial preparation Dursban. The exposure of crabs to Dursban (3.12 μg/L) showed a significant decrement of AChE activity at 24 and 48 h, whereas the BuChE was inhibited only after 24 h and no inhibition for both enzymes was observed after 72 h. Moreover, a significant repression of AChE activity was observed in both organs of C. maenas exposed to 5% of STIUE. Our experiments indicated that the measurement of AChE activity in gills and hepatopancreas of C. maenas would be useful biomarker of organophosphorous (OP) and of neurotoxic effects of STIUE in Tunisia.
In the present study biotransformation and detoxification responses to acute exposure to the poly... more In the present study biotransformation and detoxification responses to acute exposure to the polycyclic aromatic hydrocarbons benzo[a]pyrene (B[a]P) were investigated in the liver of Sparus aurata (sea bream). Sexually immature gilthead sea bream were treated by intraperitoneal injection of B[a]P (20 mg kg(-1)) for 6, 12, 24, and 48 h. B[a]P accumulation was quantified in sea bream liver by mean of gas phase chromatography (GPC-MS) after the various exposure periods. The following biological responses were measured: (1) ethoxyresorufin-O-deethylase (EROD) activity, as a phase I biotransformation parameter; (2) liver glutathione S-transferase (GST) activity as a phase II conjugation enzyme. DNA damage was assessed over time using the single-cell gel electrophoresis comet assay. B[a]P bioaccumulation in the liver resulted in a biphasic curve with an increasing uptake up to 5.55 +/- 0.67 microg g(-1) dry weight after only 6 h exposure and 4.67 +/- 0.68 microg g(-1) dry weight after 48 h exposure. EROD activity showed a nonsymmetrical bell-shaped kinetic with a maximum at 24 h and lower but significant activities at 12 and 48 h with respect to control animals. Hepatic GST activities were only significant after 48 h exposure. Comet assay showed an increase in liver cells DNA damage with a maximum after 48 h exposure reaching up to 12.17 % DNA in the tail.
The levels of metallothionein (MT), a biomarker of metal exposure, and of Cd and Cu, known as MT ... more The levels of metallothionein (MT), a biomarker of metal exposure, and of Cd and Cu, known as MT inducers, were investigated in Sparus aurata intraperitoneally injected with 500 lg/kg of Cu and Cd for 2 days. MT and metal concentrations (Cd and Cu) were determined in liver, gills and kidney. MT levels were significantly increased in all investigated tissues, with the highest value in liver of Cu as Cdtreated fishes (3.56-fold and 3.3-fold, respectively). Metal concentrations were statistically different between all tissues. Highest metal concentrations were in the liver. The higher metal concentrations and MT induction levels support the main role of MT in metal homeostasis and detoxification.
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Papers by Hamadi Boussetta