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International audience; Amongst DNA-repair processes, base-excision repair (BER) is the major mechanism for removal of DNA-base lesions caused by environmental genotoxicants. BER has been proven to exist in fish but has not been investigated in fish cell-lines, although these constitute increasingly important tools in eco-toxicological assessment. The present study aims at highlighting BER capacity of RTL-W1 and RTG-W1, two trout cell lines used in eco-genotoxicity studies. This is realized by following the kinetics of strand-break repair after a short exposure to model genotoxicants-leading predominantly to BER-specific lesions-by means of the standard alkaline and Fpg-modified comet assays. Results show that both cell lines efficiently repair single-strand breaks and base-alkylation damages within 4h and 24h, respectively. Then, the study shows that after minor modifications of the protocol, the cell extract-based BERc assay can be used to evaluate the base-incision capacity of the cell lines and its variation after exposure of the cells to a model inhibitor of BER (3-aminobenzamide) and to environmental contaminants such as cadmium and tributyltin. This work provides a basis for the further development of DNA-repair activity in fish cell-lines as a new biomarker of genotoxicity. Copyright 2013 Elsevier B.V. All rights reserved.

The original publication is available at http://www.springerlink.com/content/d2408617j6728177, peer-reviewed, Heavy metals are ubiquitous contaminants of the marine environment and can accumulate and persist in sediments. The toxicity of metal contaminants in sediments to organisms is dependent on the bioavailability of the metals in both the water and sediment phases and the sensitivity of the organism to the metal exposure. This study investigated the effects of two metal contaminants of concern (CdCl2 and CuCl2) on a battery of marine bioassays employed for sediment assessment. Cadmium, a known carcinogen and widespread marine pollutant, was found to be the least toxic of the two assayed metals in all in vivo tests. However CdCl2 was found to be more toxic to the fish cell lines PLHC-1 and RTG-2 than CuCl2. Tisbe battagliai was the most sensitive species to both metals and the Microtox® and cell lines were the least sensitive (cadmium was found to be three orders of magnitude less toxic to Vibrio fischeri than to T. battagliai). The sensitivity of Tetraselmis suecica to the two metals varied greatly. Marine microalgae are among the organisms that can tolerate higher levels of cadmium. This hypothesis is demonstrated in this study where it was not possible to derive an EC50 value for CdCl2 and the marine prasinophyte, T. suecica. Conversely, CuCl2 was observed to be highly toxic to the marine alga, EC50 of 1.19 mg l-1. The genotoxic effect of Cu on the marine phytoplankton was evaluated using the Comet assay. Copper concentrations ranging from 0.25 to 2.50 mg l-1 were used to evaluate the effects. DNA damage was measured as percent number of comets and normal cells. There was no significant DNA damage observed at any concentration of CuCl2 tested and no correlation with growth inhibition and genetic damage was found.