Exposure to phenanthrene and depuration: Changes on gene transcription, enzymatic activity and lipid peroxidation in gill of scallops Nodipecten nodosus

Abstract

Understanding the mechanism of phenanthrene (PHE) biotransformation and related cellular responses in bivalves can be an important tool to elucidate the risks of polycyclic aromatic hydrocarbons (PAHs) to aquatic organisms. In the present study it was analyzed the transcriptional levels of 13 biotransformation genes related to cytochrome P450 (CYP), glutathione S-transferase (GST), sulfotransferase (SULT), flavin-containing monooxygenase and fatty acid-binding proteins by qPCR in gill of scallops Nodipecten nodosus exposed for 24 or 96h to 50 or 200μgL(-1) PHE (equivalent to 0.28 and 1.12μM, respectively), followed by depuration in clean water for 96h (DEP). Likewise, it was quantified the activity of catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD), glutathione reductase (GR), glucose 6-phosphate dehydrogenase (G6PDH), GST and levels of lipid peroxidation. Increased transcriptional levels of CYP2UI-like, CYP2D20-like, CYP3A11-like, GSTomega-like, SULT1B1-like genes were detected in organisms exposed to PHE for 24 or 96h. In parallel, GR and GPX activities increased after 96h exposure to 200μgL(-1) PHE and G6PDH activity increased after 24h exposure to 50μgL(-1) PHE. This enhancement of antioxidant and phase I and II biotransformation systems may be related to the 2.7 and 12.5 fold increases in PHE bioaccumulation after 96h exposure to 50 and 200μgL(-1) PHE, respectively. Interestingly, DEP caused reestablishment of GPX and GR activity, as well as to the transcript levels of all upregulated biotransformation genes (except for SULT1B1-like). Bioaccumulated PHE levels decreased 2.5-2.9 fold after depuration, although some biochemical and molecular modifications were still present. Lipid peroxidation levels remained lower in animals exposed to 200μgL(-1) PHE for 24h and DEP. These data indicate that N. nodosus is able to induce an antioxidant and biotransformation-related response to PHE exposure, counteracting its toxicity, and DEP can be an effective protocol for bivalve depuration after PHE exposure.

Oxidative Stress and Apoptosis in Benzo[a]pyrene-Induced Neural Tube Defects

“…However, no increase was seen in the expressions of Gpx1 and Cat after BaP exposure. The absence of the up-regulation of these two antioxidant enzymes was also found in studies done with scallops of Chlamys farreri [50] , scallops N. nodosus [51] , and roach (Rutilus rutilus) [52] . It was demonstrated in cultured mouse embryos that SODs can significantly reduce the incidence of NTDs induced by BaP and ethanol [30] , [53] .…”

Interactive Effects of Copper, Fluorene, and Fluoranthene on Enzymatic Biomarkers and Metallothionein Levels in Crucian Carp (Carassius auratus)

“…This result demonstrated that the antioxidant system of C. auratus may fail to scavenge overproduced ROS by co-exposure to Cu 2+ and Fluo. Owing to the wide surface area in contact with water, gills are an important uptake route of organisms for waterborne pollutants [42]. Among metal ligands, induced MTs are involved in non-enzymatic homeostasis and a detoxifi cation mechanism of fi sh against metal exposure.…”

Source-specific ecological and health risks of polycyclic aromatic hydrocarbons in the adjacent coastal area of the Yellow River Estuary, China

“…85,86 However, numerous studies have demonstrated that there are other signicant factors affecting the process of PAH bioaccumulation, including environmental characterization, the number of PAH rings, and the biometric characteristics and detoxication metabolism of organisms. [87][88][89] The bioaccumulation manifested a different PAH composition to the environment, and due to the specic uptake patterns, some sources may have higher importance to the biota. Previous research has predominantly assessed pollution risks based on the concentration of pollutants, overlooking their sources that also contributed to the overall risk.…”