Aquatic Toxicology 105 (2011) 652–660 Contents lists available at SciVerse ScienceDirect Aquatic Toxicology jou rn al h om epa ge: www.elsevier.com/locate/aquatox Biochemical biomarkers and hydrocarbons concentrations in the mangrove oyster Crassostrea brasiliana following exposure to diesel fuel water-accommodated fraction Karim H. Lüchmann a , Jacó J. Mattos a , Marília N. Siebert a , Ninna Granucci a , Tarquin S. Dorrington a , Márcia C. Bícego b , Satie Taniguchi b , Silvio T. Sasaki b , Fábio G. Daura-Jorge c , Afonso C.D. Bainy a,∗ a Laboratório de Biomarcadores de Contaminac ¸ ão Aquática e Imunoquímica, Departamento de Bioquímica, Universidade Federal de Santa Catarina, Florianópolis, Brazil b Laboratório de Química Orgânica Marinha, Instituto Oceanográfico, Universidade de São Paulo, São Paulo, Brazil c Laboratório de Mamíferos Aquáticos, Departamento de Ecologia e Zoologia, Universidade Federal de Santa Catarina, Florianópolis, Brazil a r t i c l e i n f o Article history: Received 10 August 2011 Received in revised form 5 September 2011 Accepted 8 September 2011 Keywords: Diesel Biomarkers Pollution Oyster Crassostrea brasiliana a b s t r a c t Understanding the toxic mechanisms by which organisms cope to environmental stressful conditions is a fundamental question for ecotoxicology. In this study, we evaluated biochemical responses and hydro- carbons bioaccumulation of the mangrove oyster Crassostrea brasiliana exposed for 96 h to four sublethal concentrations of diesel fuel water-accommodated fraction (WAF). For that purpose, enzymatic activi- ties (SOD, CAT, GPx, GR, G6PDH, GST and GGT), HSP60 and HSP90 immunocontent and lipid peroxidation (LPO) levels were determined in the gill and digestive gland of oysters and related to the hydrocarbons accumulated in the whole soft tissues. The results of this study revealed clear biochemical responses to diesel fuel WAF exposure in both tissues of the oyster. The capacity of C. brasiliana to bioaccumulate aliphatic and aromatic hydrocarbons in a dose-dependent manner is a strong indication of its suitability as a model in biomonitoring programs along the Brazilian coast, which was also validated by the response of the antioxidant defenses, phase II biotransformation and chaperones. HSP60 levels and GGT activity were the most promising biomarkers in the gill, while GST and GR activities stood out as suitable biomarkers for the detection of diesel toxicity in the digestive gland. The decrease of SOD activity and HSP90 levels may also reflect a negative effect of diesel exposure regardless the tissue. The present results provide a sound preliminary report on the biochemical responses of C. brasiliana challenged with a petroleum by-product and should be carefully considered for use in the monitoring of oil and gas activities in Brazil. © 2011 Elsevier B.V. All rights reserved. 1. Introduction The recent discovery of potentially massive oil reserves in Brazil- ian offshore waters has projected the country into becoming one of the world’s largest producers of crude oil (Wertheim, 2009). There is, therefore, a need for monitoring of petroleum industry activi- ties and the possibility of marine contamination. Oil exploration, production and transport potentially expose marine organisms to petrochemical compounds; hence, a pollution-monitoring pro- gram is a priority to assess the effects of petroleum by-products on such organisms. It may also enhance any decision-making in the ∗ Corresponding author. Tel.: +55 48 3721 6391; fax: +55 48 3721 9672. E-mail addresses: khluchmann@gmail.com (K.H. Lüchmann), jacomattos@hotmail.com (J.J. Mattos), mariliasiebert@gmail.com (M.N. Siebert), ninnagranucci@gmail.com (N. Granucci), tarquindorrington@gmail.com (T.S. Dorrington), marciabicego@usp.br (M.C. Bícego), satie@usp.br (S. Taniguchi), ssasaki@usp.br (S.T. Sasaki), daurajorge@gmail.com (F.G. Daura-Jorge), bainy@mbox1.ufsc.br (A.C.D. Bainy). public and private sectors on the environmental effects of accidents, such as the recent BP oil spill in the Gulf of Mexico. Filter-feeding mollusks, such as oysters, play a significant role as sentinel organisms in monitoring programs due to their capacity to bioaccumulate environmental contaminants as well as to respond to their presence (Bebianno and Barreira, 2009; Solé et al., 2007). Moreover, they are sessile, globally distributed and economically important. Chemical analysis of contaminants in bivalve tissues has been recommended for biomonitoring (Solé et al., 2007), which gives an indication of the bioavailable fraction of environmental contamination and of direct exposure to chemicals. However, they do not necessarily reveal potential biological effects of the contam- inants (Baumard et al., 1999) and biomarkers have been developed to detect and evaluate the effects of exposure to contaminants in the aquatic environment (Richardson et al., 2008). Brazilian oyster production has expanded considerably over the past decade, and the native mangrove oyster Crassostrea brasil- iana has become prevalent in oyster farms in Brazil (Pie et al., 2006). In addition, this species occurs naturally along the entire 0166-445X/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.aquatox.2011.09.003