Integrated transcriptomics and metabolomics analyses reveal benzo[a]pyrene enhances the toxicity of mercury to the Manila clam, Ruditapes philippinarum

• Published in: Ecotoxicology and environmental safety Vol. 213; p. 112038
• Main Authors: Jiang, Weiwei, Fang, Jinghui, Du, Meirong, Gao, Yaping, Fang, Jianguang, Jiang, Zengjie
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 15.04.2021; Elsevier
• Subjects: Animals; Benzo(a)pyrene - toxicity; Benzo[a]pyrene; Bivalvia - metabolism; Bivalvia - physiology; Computational Biology; Gills - metabolism; Mercury; Mercury - analysis; Mercury - toxicity; Metabolomics; Ruditapes philippinarum; Seafood - analysis; Toxicological responses; Transcriptome - physiology; Transcriptomics; Water Pollutants, Chemical - toxicity; Toxicological responses; Metabolomics; Benzo[a]pyrene; Transcriptomics; Mercury; Ruditapes philippinarum
• ISSN: 0147-6513; 1090-2414
• DOI: 10.1016/j.ecoenv.2021.112038

Mercury (Hg2+) and benzo[a]pyrene (BaP) are ubiquitous and persistent pollutants with multiple toxicities in bivalve molluscs. Here, the toxicological responses in the gills of Manila clams, Ruditapes philippinarum, to Hg2+ (10 μg L−1), BaP (3 μg L−1), and their mixture were analysed using transcriptomics and metabolomics approaches. Comparisons of the transcriptomes and metabolomes of Hg2+-and/or BaP-treated clams with control animals revealed the involvement of the detoxification metabolism, immune defence, energy-related pathways, and osmotic regulation in the stress response of R. philippinarum. Exposure to Hg2+ alone primarily enhanced the detoxification and energy metabolic pathways by significantly increasing the expression of genes associated with heat-shock proteins and oxidative phosphorylation. However, co-exposure to Hg2+ and BaP caused greater immunotoxicity and disrupted detoxification metabolism, the TCA cycle, glycolysis, and ATP generation. The expression levels of cytochrome P450 1A1 (CYP1A1), multidrug resistance-associated protein 1 (MRP1), and myosin (MYO), and the activity of electron transport system (ETS) in gills were detected, supporting the underlying toxic mechanisms of Hg2+ and BaP. We suggest that the presence of BaP enhances the toxicity of Hg2+ by 1) hampering the detoxification of Hg2+, 2) increasing the immunotoxicity of Hg2+, and 3) constraining energy availability for clams. [Display omitted] •A synergistic toxic effect of Hg2+ and BaP was observed in R. philippinarum.•BaP hampers the detoxification of Hg2+ in clams.•BaP aggravates the immunotoxicity of Hg2+ in clams.•BaP constrains the energy available for clam responses to Hg2+ stress.