Dellali Mohamed

University of Carthage | UCAR · Département de Sciences de la vie

The Pipper nigram (P. nigram) leaf extract was used for the biosynthesis of copper oxide nanoparticles (CuO NPs) and the successful formation of the resultant product was confirmed through several physicochemical techniques. The chemical structure and the elemental composition were analysed through Fourier transform infrared (FTIR) and energy dispe...

The aim of this work was to study the ecotoxicological effects of an endocrine disruptor triclosan on the clam Ruditapes decussatus. The bivalves were exposed to three concentrations of this biocide (C1 = 100 ng/L, C2 = 200 ng/L and C3 = 500 ng/L) for three and seven days. The impact was assessed at the gills and digestive glands, through activitie...

The multiple impacts of polycylic aromatic hydrocarbon on the aquatic invertebrates were rarely assessed in a chronic way and multiple-species experiments, despite the clear advantage of better mimicking natural conditions compared to traditional acute and single-species-focused toxicological experiments. The application of such an approach is esse...

As a result of the wide use of Titanium (Ti) compounds in various products, Ti and Ti nanoparticles (nTi) are released into aquatic environments, inducing varying degrees of toxicity on aquatic fauna. Ulva lactuca, green macroalgae commonly found in coastal areas, has been extensively studied due to its worldwide distribution and capacity to accumu...

Plastics pollution in marine environment has become an issue of increasing scientific concern. This work aims to study the temporal and spatial distribution of plastics in sediments from three different Tunisian ecosystems; Rimel Beach, Bizerta lagoon and Ichkeul lake. Sediment sampling was conducted in surface (2 cm) and depth (15 cm) during sprin...

Toxicity of silver nanoparticles on the clam Ruditapes decussatus assessed through biomarkers and clearance rate .

The current work investigated the ecotoxicological effects induced by Titanium Dioxide(TiO2) nanoparticles (NPs), used at three different concentrations (C1 = 10 μg·L−1, C2 = 100 μg·L−1 and C3 = 1000 μg·L−1) in a laboratory experiment, on the freshwater mussel Unio ravoisieri. Biochemical analyses of gills and digestive glands revealed a stress-rel...

The current bioassay aims the evaluation of the ecotoxicity of the silver nanoparticles (NPs) (100 and 200 μgL-1) on Ruditapes decussatus after 48 hours and 7 days of its exposure. The biochemical analyses performed at gills and digestive glands showed a disturbance of the antioxidant system following the exposure of clams to Ag NPs. The catalase a...

This study evaluated the biomarker responses indicative of exposure to Benzo[a] Pyrene (B[a]P) in Mytilus galloprovincialis and Ruditapes decussatus. A significant increase of the total oxyradical scavenging capacity (TOSC) was observed after seven days of exposure to two concentrations of B[a]P (100 and 300 μg.l⁻¹), in the digestive gland with the...

The cockle Cerastoderma edule was exposed to four concentrations (5, 10, 20 and 70 μg L-1) of carbamazepine (CBZ). This anticonvulsant was found to alter the mussel behavior of by reducing its clearance rate (CR). Analysis of CBZ accumulation in tissues of C. edule was carried out using HPLC-UV after 48 or 96 hours of exposure. In addition, an over...

The toxicity of copper, cadmium, and dieldrin in adult Gammarus locusta (a marine amphipod) is currently unclear. Thus, G. locusta from the North Lake of Tunis were subjected to acute toxicity tests to assess LC50s at 48–96 h and to biomarker response tests through the assessment of catalase and acetylcholinesterase activities and malondialdehyde l...

Context The Au-TiO2NPs have a wide range of applications and can easily enter the cells. Due to their properties, they can cause toxicity. Objective it was aimed to test the toxic effects of Au-TiO2NPs in brain, heart, kidney and liver of rats in this work. Materials and methods All used rats in this work were treated using diverse concentration...

Several studies have been performed on the effects of nanoparticles on aquatic life. However, most of them investigated marine organisms, not freshwater organisms. This study investigated biomarker responses after exposure for 48 h and 7 days to newly made gold and titanium dioxide (Au/TiO2) metallic nanoparticles (MNPs) (100 and 200 μg·L⁻¹) using...

A laboratory bioassay was performed to assess the ecotoxicity of ciprofloxacin on a meiobenthic nematodes community from Bizerte lagoon (NE Tunisia). Four ciprofloxacin doses [D1 (50 µg/g), D2 (100 µg/g), D3 (200 µg/g), and D4 (500 µg/g)] were applied to the substrate, and responses were studied after one month. Discernible differences were observe...

Cypermethrin (Cyp) is a kind of pyrethroids compound that is broadly used against different species of insects and pests. Cyp can also elicit a range of neurotoxic, immunotoxic, genotoxic and reproductive toxic effects on various experimental organisms. The aim of this study was to evaluate the protective effects of Hibiscus sabdariffa against the...

Nanoparticle decoration with noble metal represents a promising alternative to improve their photocatalytic and photovoltaic properties. However, toxicity can be influenced by such modification, as the bioavailability of these substances may be influenced. To understand how decoration influences the NP impacts in marine ecosystems, we exposed suspe...

Nanoparticle decoration with noble metal represents a promising alternative to improve their photocatalytic and photovoltaic properties. However, toxicity can be influenced by such modification, as the bioavailability of these substances may be influenced. To understand how decoration influences the NP impacts in marine ecosystems, we exposed suspe...

Context: Nanoparticles may cause adverse environmental effects but there is limited information on their interactions with marine organisms. Objective: Our aim was to examine the effects of triangular gold nanoparticles (Tr-Au NPs) on the clam, Ruditapes decussatus. Materials and methods: Clams were exposed to Tr-Au1 = 5 µg/L and Tr-Au2 = 10 µg/L f...

Mediterranean mussels Mytilus galloprovincialis is among the most widely used bioindicators, and anthracene (AN) is one of the most commonly found hydrocarbons in the aquatic environment. M. galloprovincialis were exposed to nominal concentrations of 0.05, 0.15 and 0.4 μg/L AN. Chemical analysis using high-performance liquid chromatography revealed...

Pyrethroids are contaminants found in the aquatic environment, and their toxicological effects on aquatic organisms have received extensive attention. However, the impact on freshwater bivalve of exposure to these chemicals is still largely unknown. Freshwater mussels Unio ravoisieri were exposed to two nominal permethrin (PM) concentrations C1 = 5...

This study aimed at analyzing the impact of a toxic polyaromatic hydrocarbon (PAH), anthracene (ANT), on Ruditapes decussatus collected from a Tunisian coastal lagoon (Bizerte Lagoon). Filtration rates, several antioxidant enzymes-superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione t...

The present study was focused on the assessment of Catalase (CAT) and Acetylcholinesterase (AChE) activities in Mediterranean clams (Ruditapes decussatus) exposed to 50, 100 and 150 μg/L of Permethrin for 5, 10, 15, 20 and 25 days. In water, the measured concentrations of Permethrin in the treated aquariums were respectively 16.66, 38.24 and 55.61...

The effects of permethrin (PER) on a panel of antoxidant enzymes; superoxide dismutase (SOD), catalase (CAT) and glutathione S-transferase (GST) and indices of protein oxidation status (carbonylation and free thiols) were determined in digestive gland and gills of the clam Ruditapes decussatus. Animals were exposed to 100 ppb PER for 2 days. These...

The effects of seawater acidification caused by increasing concentrations of atmospheric carbon dioxide (CO2), combined with other climatic stressors, were studied on 3 coastal Mediterranean bivalve species: the mussel Mytilus galloprovincialis and the clams Chamelea gallina and Ruditapes decussatus. CO2 perturbation experiments produced contrastin...

Carpet shell clam populations on the Tunisian coastline are susceptible to several microbial pathogen challenges. In this study we report the results of five years' surveillance, conducted from January 2004 till June 2009, for detection of Perkinsosis and brown ring disease (BRD). The survey covered three sites of natural populations of Ruditapes d...

The occurrence and spread of brown ring disease (BRD) to several northern Mediterranean coasts is described. We report the results of a 6-y surveillance of BRD in natural populations of carpet shell clams (Ruditapes decussatus) in 14 zones along the Gulf of Gabes in Tunisia (southern Mediterranean Sea). BRD symptoms in adult animals resulting from...

Microcosms were used to assess the impact of permethrin on the abundance and diversity of free-living marine nematodes. The nematodes were exposed to three permethrin concentrations (50, 100 and 150 μg l-1), and the effects were examined after 25 days. The abundances of nematodes at all permethrin concentrations significantly exceeded those in the...

Marine gastropods, exposed to anthropogenic pollution, accumulate high chemical concentrations in their tissues, especially in the digestive glands. An evaluation of the impacts of cadmium (Cd) and permethrin (Perm), coupled with reproductive events (pre-spawning and post-spawning phase) throughout the year, was attempted by measuring catalase (CAT...

Five biomarkers, catalase (CAT) activity, glutathione-S-transferase (GST) activity, the neural transmitter enzyme acetylcholinesterase (AChE), reduced glutathione (GSH) and malondialdehyde (MDA) levels were measured in specimens of Fulvia fragilis collected from Bizerta lagoon (Tunisia). Results demonstrated that F. fragilis showed differential bio...

To characterize polycyclic aromatic hydrocarbon (PAH)-degrading bacteria from sediments of the Bizerte lagoon, and to determine their ability to resist other pollutants such as antibiotics and heavy metals. More than 100 strains were isolated for their ability to use fluoranthene as the sole carbon and energy source. Most of them showed antibiotic...

This study aims to evaluate the health status of Bizerta lagoon using a sentinel species, the Neogastropod Murex trunculus. Trace metal concentrations (Cd, Cu and Zn) in the foot and digestive gland, and biomarkers such as acetylcholinesterase (AChE), catalase (CAT) and glutathione transferase (GST) activities in the digestive gland, were determine...

La maladie de l'anneau brun, altération de la coquille susceptible d'affecter diffé-rentes espèces de palourdes, a été incriminée parmi les causes de mortalité de populations de ce bivalve dans différents pays en Méditerranée. Sa prospection a été réalisée chez différentes espèces de bivalves (Cerastoderma glaucum, Pecten glaber, Donax trunculus et...

Brown ring disease (BRD) of bivalves is characterized by an abnormal brown deposit of organic nature, which generally adheres in the inner face of the valves, usually between the pallial line and the edge of the shell, forming a brown ring. This disease was first extensively described in various clam species in different Mediterranean countries and...

This study aims to characterize the effect of high organic loads, produced by a mussel farm in the Bizerte Lagoon, on the distribution of bacterial densities of, especially, marine heterotrophic bacteria and Vibrionaceae in the water column and in the sediment. Five sites located along a distance gradient from the mussel breeding ground were survey...

This study aims to characterize the effect of high organic loads, produced by a mussel farm in the Bizerte Lagoon, on the distribution of bacterial densities of, especially, marine heterotrophic bacteria and Vibrionaceae in the water column and in the sediment. Five sites located along a distance gradient from the mussel breeding ground were-survey...

Cadmium, copper and zinc concentrations (in whole soft body and in tissues) were measured in Hexaplex trunculus collected from the Bizerta lagoon in Tunisia. An evaluation of the biological effects of the most toxic metals (cadmium and copper) and of two organics (carbofuran and lindane), present in the sediments of the Bizerta lagoon, was attempte...

From May 1998 to May 1999, the clams Ruditapes decussatus were collected each month at three stations of the Bizerta lagoon. This paper represents a synthesis between the results already published of catalase (CAT) activity, of glutathione S-transferase (GST) activity and acetylcholinesterase (AChE) activity measured in the clams. Hydrological para...

The variations of acetylcholinesterase activity, considered to be a biochemical biomarker of organophosphorus and carbamate compounds, was followed in Mediterranean clams (Ruditapes decussatus) and mussels (Mytilus galloprovincialis) as a function of season and sampling sites in the lagoon of Bizerta (Tunisia). Results show that acetylcholinesteras...

Pour valider in situ certains biomarqueurs comme outils de biosurveillance de la lagune de Bizerte (Tunisie), des prélèvements mensuels d’eau, de sédiment et de bivalves (Ruditapes decussatus et Mytilus galloprovincialis) ont été réalisés de mai 98 à mai 99 au niveau de 7 stations. Divers résultats ont été obtenus. Sur le plan écologique : Les dive...

The variations of catalase activity, which is a biochemical biomarker of exposure to an oxidative stress, were followed month by month (from May 1998 to May 1999) in Mediterranean clams (Ruditapes decussatus) collected at three stations (J, A and F), and mussels (Mytilus galloprovincialis) collected at two stations (J and C) in Lake Bizerte (Tunisi...

La presente etude tente de caracteriser les populations de Vibrionaceae presentes dans la lagune de Bizerte entre mai 1998 et mai 1999. Ce suivi annuel a ete realise au niveau de 7 stations en considerant les compartiments aqueux, sedimentaire et biologique (palourdes et moules). L'isolement des Vibrionaceae sur milieu selectif TCBS (thiosulfate -...

This study aims to characterize the effect of high organic loads, produced by a mussel farm in the Bizerte Lagoon, on the distribution of bacterial densities of, especially, marine heterotrophic bacteria and Vibrionaceae in the water column and in the sediment. Five sites located along a distance gradient from the mussel breeding ground were survey...