Using environmental proteomics to assess pollutant response of Carcinus maenas along the Tunisian coast.

Biochemical responses to pollutants were studied at four Tunisia littoral sites using Carcinus maenas as a bioindicator. Proteomic analysis was used to assess the global impact of complex pollution mixtures, and to provide new biomarkers and basic insights into pollutant toxicity. Metal contents and metallothionein levels followed a gradient based on sampling sites: Bizerte ≫ Teboulba > Gargour~Mahres. Approximately 900 and 700 spots were resolved in digestive glands and gills, respectively. Gills from Bizerte animals had the maximum number of altered spots, mostly upregulated. In other locations, the number of altered spots in gills decreased in parallel to total metals in in the following order: Teboulba > Gargour > Mahres (mostly downregulated). Out of the 39 spots excised, ten proteins were identified in digestive glands and eight in gills. Digestive glands of Bizerte crabs had higher levels of ferritin, three vitellogenin forms and mannose-binding protein, while Gargour crabs had higher levels of four cryptocyanin forms. Gills of Bizerte crabs had higher levels of ferritin, three vitellogenins forms, lectin 4C, actin, and collagenolytic serine protease. Proteins with altered expression in crabs from Tunisia littoral are related to molting, oxidative stress and inflammation, innate immune response, and proteolysis.

Integrated assessment of biochemical responses in Mediterranean crab (Carcinus maenas) collected from Monastir Bay, Tunisia.

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.

Acute effects of chlorpyryphos-ethyl and secondary treated effluents on acetylcholinesterase and butyrylcholinesterase activities in Carcinus maenas.

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 microg/L, whereas the BuChE was inhibited only at higher concentration 7.82 microg/L of commercial preparation Dursban. The exposure of crabs to Dursban (3.12 microg/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.

Seasonal variation of oxidative stress biomarkers in clams Ruditapes decussatus sampled from Tunisian coastal areas.

Seven (7) sites from to the Tunisian coastal area were monitored through four seasons using several oxidative stress biomarkers including lipid peroxidation. Catalase (CAT) specific activity was determined in clam Ruditapes decussatus digestive gland. Lipid peroxidation was assessed in the same tissues using malondialdehyde (MDA) concentration, neutral lipid (NL) and lipofuscin accumulation. Results show that catalase specific activity varies between sites and fluctuates in time. The highest CAT activities were recorded in sites from Bizerta Lagoon and sites neighbouring Sfax city. Malondialdehyde accumulation in digestive gland cells seems to be very pronounced in animals sampled in summer and autumn. Digestive gland sections of clams sampled from reported heavy metal polluted sites exhibited higher volume density of residual bodies. Our results showed that the neutral lipids and lipofuscin content in clam's digestive gland are more sensitive to general stress as compared to other biomarkers, and could be used successfully in clams as early warning tools in field biomonitoring programs.