Assessment of single and combined effects of bisphenol-A and its analogue bisphenol-S on biochemical and histopathological responses of sea cucumber Holothuria poli.

Bisphenols (BPs) are among emerging pollutants that have been frequently detected in different compartments of marine ecosystems and elicited great concern due to their potential toxicity to marine organisms. This work aimed to investigate the toxicity of bisphenol A (BPA) and bisphenol S (BPS) on oxidative stress markers, neurotoxicity and histopathological alterations in sea cucumbers (Holothuria poli). The results showed that exposure to 200 µg/L of BPA and BPS produced oxidative stress, neurotoxicity in the digestive tract and respiratory tree, and several types of histopathological lesions in tissues of the respiratory tree of the sea cucumber, posing a health hazard to this aquatic organism. In addition, BPA has greater effects than BPS on the generation of oxidative stress marked by the inductions of catalase (CAT), glutathione S-transferase (GST) and malondialdehyde (MDA) levels and neurotoxicity shown by the decrease in acetylcholinesterase activity (AChE). The respiratory tree of sea cucumbers might be an appropriate tissue for assessing CAT, MDA and AChE activity levels, which are reliable biomarkers that may be useful in marine biomonitoring studies. Evaluation of histopathological lesions of the respiratory tree suggests that BPA and BPS and their mixture cause various tissue alterations that may be associated with oxidative stress damage and neurotoxicity. In conclusion, this study showed that oxidative stress (CAT and MDA) and neurotoxicity (AChE) markers, as well as respiratory tree lesions, are sensitive biomarkers for the assessment of BPA and BPS toxicity in sea cucumbers.

Assessment of the individual and mixture toxicity of cadmium, copper and oxytetracycline, on the embryo-larval development of the sea urchin Paracentrotus lividus.

Multiple pollutions by trace metals and pharmaceuticals have become one of the most important problems in marine coastal areas because of its excessive toxicity on organisms living in this area. This study aimed to assess the individual and mixture toxicity of Cu, Cd, and oxytetracycline frequently existing in the contaminated marine areas and the embryo-larval development of the sea urchin Paracentrotus lividus. The individual contamination of the spermatozoid for 1 h with the increasing concentrations of Cd, Cu, and OTC decreases the fertility rate and increases larvae anomalies in the order Cu > Cd > OTC. Moreover, the normal larva frequency and the length of spicules were more sensitive than the fertilization rate and normal gastrula frequency endpoints. The mixture toxicity assessed by multiple experimental designs showed clearly that concentrations of Cd, Cu, and OTC superior to 338 µg/L, 0.56 µg/L, and 0.83 mg/L, respectively, cause significant larva malformations.

Assessment of toxic interactions between deltamethrin and copper on the fertility and developmental events in the Mediterranean sea urchin, Paracentrotus lividus.

Deltamethrin pesticide and copper have intensively been used in agriculture and industrial activities and can finally reach the marine ecosystem at high concentrations affecting the health of organisms. In this study, we assessed under laboratory conditions the toxic interactions between deltamethrin and copper and their effects on the fertility rate, cell mitotic division rate, and embryo developmental events of the sea urchin (Paracentrotus lividus). The exposure of sperm to increasing concentrations of deltamethrin (6.10(-5) and 6.10(-2) µg/L) and copper (50 and 100 µg/L) or to their mixture (6.10(-5) µg/L of deltamethrin and 50 µg/L of CuSO4) caused a significant alteration on the fertilizing capability of spermatozoids. Concentration-dependent toxic effects on the early cleavage in P. lividus were observed in groups treated with copper, deltamethrin, and their mixture. The kinetics of early divisions was accelerated and the average size of pluteus larvae was decreased under pollutant treatments. Several developmental anomalies were identified in pluteus, including crossed skeletal tips at the hood apex, joined or atrophied arms, and alteration of general larva shape. In conclusion, the sea urchin represents a suitable and sensitive model for testing the toxicity and the effects of deltamethrin pesticide and copper in sea water. In addition, the sensitivity of various end points to studied contaminants, proved their utility in the infield biomonitoring studies.

Mixture toxicity assessment of nickel and chlorpyrifos in the sea bass Dicentrarchus labrax.

The present research work was designed to study Dicentrarchus labrax biotransformation and detoxification responses to acute exposure to nickel (Ni) and chlorpyrifos (CHP). Sexually immature sea bass were treated by intraperitoneal injection of nickel chloride (500 µg kg⁻¹), chlorpyrifos (10 mg kg⁻¹), and their binary mixture for 1, 3, and 7 days. Ni and CHP accumulation was quantified in liver after the exposure periods. The following biological responses were measured: (1) NADPH cytochrome P450 reductase (NCR) activity, as phase I biotransformation parameter; (2) gluthathione S-transferase (GST) activity as a phase II conjugation enzyme, acetylcholinesterase activity, and metallothionein (MT) content. Ni bioaccumulation in the liver resulted in an increasing uptake up to 15.48 µg g⁻¹ wet weight (Ni-treated animals) and 16.73 µg g⁻¹ wet weight (mixture-treated animals) after 7 days of exposure. CHP accumulation showed a distinct pattern in animals exposed to the mixture of chemicals in comparison with CHP-treated animals. NCR activity exhibited a marked activation in CHP and mixture-treated animals. GST activity was significantly increased starting from 1 day exposure in CHP-treated animals and after 3 days in Ni-treated animals. MT accumulation increased in all conditions, with a marked synergetic effect after 7 days of exposure. These data should be carefully considered in view of the biological effects of mixture pollutants, particularly in fish farming conditions.

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.

Metallothionein induction by Cu, Cd and Hg in Dicentrarchus labrax liver: assessment by RP-HPLC with fluorescence detection and spectrophotometry.

Metallothionein was quantified in sea bass Dicentrarchus labrax intraperitoneally (i.p.) injected with different Cu, Cd and Hg doses (50-250 microg kg(-1) wet wt) after 48 h exposure. A distinct peak with 16.8 min retention time was obtained by reversed-phase high performance liquid chromatography coupled to fluorescence detection (RP-HPLC-FD) with the three metals. Total metallothionein levels assayed in unheated liver extracts by RP-HPLC-FD were significantly higher (1.3-1.95-fold) than those obtained by the well-established spectrophotometric method. In the RP-HPLC-FD method, metallothionein increased linearly with Cu and Hg doses, being saturated beyond 100 mug kg(-1) Cd. Maximum induction was obtained at 100 microg kg(-1) Cd (5.3-fold), and 250 microg kg(-1) Cu or Hg (8- and 5.1-fold, respectively). At low doses no metallothionein induction was shown by the less sensitive spectrophotometric assay.