Effect of linear alkylbenzene mixtures and sanitary sewage in biochemical and molecular responses in pacific oyster Crassostrea gigas

Abstract

Urban effluents are rich in nutrients, organic matter, pharmaceuticals and personal care products (PPCPs), pesticides, hydrocarbons, surfactants, and others. Previous studies have shown that oysters Crassostrea gigas accumulate significant levels of linear alkylbenzenes (LABs) in sanitary sewage contaminated sites, but there is little information about its toxicological effects in marine bivalves. The aim of this study was to analyze the transcription of genes in two tissues of C. gigas exposed for 12, 24, and 36 h to LABs or sanitary sewage. Likewise, the activity of antioxidant and biotransformation enzymes was measured in oysters exposed for 36 h in all groups. Oysters exposed to LABs and oysters exposed to sanitary sewage showed different patterns of transcriptional responses. LAB-exposed oysters showed lower level of biological responses than the oysters exposed to sanitary sewage. Despite the ability of the oyster C. gigas to accumulate LABs (28-fold), the data indicate that these contaminants are not the cause for the transcriptional responses observed in oysters exposed to sanitary sewage. Possibly, the biological changes observed in the sanitary sewage-exposed oysters are associated with the presence of other contaminants, which might have caused synergistic, additive, or antagonistic effects. The results show that FABP-like and GST-ω-like messenger RNAs (mRNAs) have a rapid response in tissues of oyster C. gigas exposed to sanitary sewage, suggesting a possible protective response and a role in maintaining homeostasis of these organisms.

First evidence of viral and bacterial oyster pathogens in the Brazilian coast

“…Published primer pairs were used: C2/C6 (Arzul, Renault, Lipart, & Davison, ), C9/C10 (Barbosa‐Solomieu, Miossec, Vázquez‐Juárez, Ascencio‐Valle, & Renault, ), OsHVDP‐For/OsHVDP‐Rev (Webb, Fidler, & Renault, ) and Gp3/Gp4 (Arzul, Nicolas, Davison, & Renault, ), designed for OsHV‐1; VSPN‐F/VSPN‐R (Lee, Wang, Law, Wu, & Kong, ), designed for V. splendidus ; and AesF1/AesR1 (Saulnier, De Decker, & Haffner, ), designed for V. aestuarianus (Table S1). The presence of PCR inhibitors was investigated using an internal control (glyceraldehyde 3‐phosphate dehydrogenase; Flores‐Nunes et al., ). Positive controls consisted of DNA extracted from oysters experimentally infected with OsHV‐1 μVar, V. splendidus LGP32 (= V. tasmaniensis ) or V. aestuarianus 02/41 (kindly provided by Dr. Caroline Montagnani; University of Montpellier 2, France).…”

“…For the molecular investigation of OsHV-1 and the Gram-negative bacteria V. splendidus and V. aestuarianus, samples were submitted to an initial high-throughput screening using real-time PCR (Webb, Fidler, & Renault, 2007) and Gp3/Gp4 (Arzul, Nicolas, Davison, & Renault, 2001), designed for OsHV-1; VSPN-F/VSPN-R (Lee, Wang, Law, Wu, & Kong, 2002), designed for V. splendidus; and AesF1/AesR1 (Saulnier, De Decker, & Haffner, 2009), designed for V. aestuarianus (Table S1). The presence of PCR inhibitors was investigated using an internal control (glyceraldehyde 3-phosphate dehydrogenase; Flores-Nunes et al, 2015). PCR products obtained using the primer pairs C9/C10 (predicted product of~200 bp and unspecific product of~400 bp) and Gp3/Gp4 were purified and sequenced.…”

Molecular and cellular effects of contamination in aquatic ecosystems

“…As put by Miracle et al (2003):'If a well thought-out approach is neglected during experimental design and data interpretation (of molecular technologies), then we are simply left with standard toxicology in Technicolor'. Likewise, we must understand the molecular and cellular tools and give emphasis to their technical quality (Harris et al 2014;Wolf et al 2015); in particular, as ecotoxicologist are not necessarily trained as molecular biologists, bioinformaticians or histopathologists, but still are using and applying these techniques.…”

“…Studies that involved the evaluation of effects on proteome level are even less frequent. An example of the use of proteomics is provided in this issue by the study of Flores-Nunes et al 2015a, b. Hook et al (2015 exemplifies how to utilize contaminant-specific gene expression patterns for the purpose of a toxicity identification evaluation (TIE)-like approach. The evaluation of stressor-specific gene response patterns was also addressed in the study of Karray et al (2015a, b, c) in the marine bivalve Cerastoderma glaucum exposed to cadmium or industrial effluents containing high concentrations of metals.…”

“…Two studies employed the Pacific oyster, Crassostrea gigas, as model organism to evaluate the transcriptome (Serrano et al 2015) and proteome (Flores-Nunes et al 2015a, b responses towards exposure to ibuprofen and urban sewage, respectively. Environmentally relevant concentrations of the nonsteroidal anti-inflammatory drug ibuprofen produced increased transcription of cytochrome P450 genes, glutathione S-transferase isoforms, as well as the cyclooxygenase-like and the fatty acid-binding protein-like features, and alterations on antioxidant and auxiliary enzymes, which could, in the long term, cause damages to exposed individuals of C. gigas.…”