Integrated biological responses and tissue-specific expression ofp53andrasgenes in marine mussels following exposure to benzo(α)pyrene and C₆₀fullerenes, either alone or in combination

Abstract

We used the marine bivalve (Mytilus galloprovincialis) to assess a range of biological or biomarker responses following exposure to a model-engineered nanoparticle, C fullerene, either alone or in combination with a model polycyclic aromatic hydrocarbon, benzo(α)pyrene [B(α)P]. An integrated biomarker approach was used that included: (i) determination of 'clearance rates' (a physiological indicator at individual level), (ii) histopathological alterations (at tissue level), (iii) DNA strand breaks using the comet assay (at cellular level) and (iv) transcriptional alterations of p53 (anti-oncogene) and ras (oncogene) determined by real-time quantitative polymerase chain reaction (at the molecular/genetic level). In addition, total glutathione in the digestive gland was measured as a proxy for oxidative stress. Here, we report that mussels showed no significant changes in 'clearance rates' after 1 day exposure, however significant increases in 'clearance rates' were found following exposure for 3 days. Histopathology on selected organs (i.e. gills, digestive glands, adductor muscles and mantles) showed increased occurrence of abnormalities in all tissues types, although not all the exposed organisms showed these abnormalities. Significantly, increased levels of DNA strand breaks were found after exposure for 3-days in most individuals tested. In addition, a significant induction for p53 and ras expression was observed in a tissue and chemical-specific pattern, although large amounts of inter-individual variability, compared with other biomarkers, were clearly apparent. Overall, biological responses at different levels showed variable sensitivity, with DNA strand breaks and gene expression alterations exhibiting higher sensitivities. Furthermore, the observed genotoxic responses were reversible after a recovery period, suggesting the ability of mussels to cope with the toxicants C and/or B(α)P under our experimental conditions. Overall, in this comprehensive study, we have demonstrated mussels as a suitable model marine invertebrate species to study the potential detrimental effects induced by possible genotoxicants and toxicants, either alone or in combinations at different levels of biological organisation (i.e. molecular to individual levels).

Assessing the impact of Benzo[a]pyrene on Marine Mussels: Application of a novel targeted low density microarray complementing classical biomarker responses

“…It does not require any licence from any authorities in the UK as they are not protected or endangered species. This is in line with our previous studies using this species collected from this site [12,13]. This site has been used previously as a reference location for ecotoxicological studies [31].…”

“…Water samples (9 mL) were collected in glass vials and dichloromethane (1 mL, HPLC grade, Rathburn Chemicals Ltd., UK) was added before storage in the dark at 4°C [13]. Prior to analysis, B[a]P d12 (15 μL of a 3 mg/L solution in acetone) was spiked as an internal standard.…”

“…It is one of the US EPA’s priority pollutants. As one of the most commonly tested compounds in ecotoxicology [12,13], B[a]P has been shown to produce toxic effects in aquatic organisms across a range of biological levels. For example, B[a]P induces xenobiotic metabolism in fish and marine polychaetes [14,15], causes developmental abnormalities and genotoxic effects in the embryos of oysters, annelids and zebrafish[16,17,18].…”

“…In addition, B[a]P has been shown to interact with other pollutants (e.g. engineered nanoparticles) that could alter the potential toxic effects [13,26,27]. As such, mixture effects become more prominent in ecotoxicology and environmental protection [28].…”

Novel ABCB1 and ABCC Transporters Are Involved in the Detoxification of Benzo(α)pyrene in Thick Shell Mussel, Mytilus coruscus

“…The selected Bap conservation in this experiment was performed according to Di et al (2011) and represented at par with the low, medium, and high concentrations. The concentrations of Bap in water samples were determined by GC-MS method according to Di et al (2011Di et al ( , 2017. Briefly, an Agilent 5975 GC-MS system was calibrated with commercial Bap standards to generate a standard curve.…”