A novel biomarker for marine environmental pollution of CAT from Mytilus coruscus

• Published in: Marine pollution bulletin 2018-02, Vol.127, p.717-725
• Main Authors: Bao, Miaomiao, Huo, Liping, Wu, Jiong, Ge, Delong, Lv, Zhenming, Chi, Changfeng, Liao, Zhi, Liu, Huihui
• Format: Article
• Language: English
• Subjects: 3' Untranslated regions; 5' Untranslated Regions; Aeromonas hydrophila - pathogenicity; Amino Acid Sequence; Amino acid sequences; Amino acids; Animals; Bacteria; Bacterial infection; Biomarkers; Biomarkers - metabolism; Catalase; Catalase - genetics; Catalase - metabolism; Catalysis; China; Detection; DNA; Environmental Monitoring - methods; Environmental stress; Enzymatic activity; Enzyme activity; Enzymes; Fluorescence; Gene expression; Gonads; Heavy metals; Heme; Hepatopancreas; Hepatopancreas - drug effects; Hepatopancreas - enzymology; Homology; Marine environment; Marine molluscs; Marine pollution; Metal concentrations; Metals; Metals, Heavy - analysis; Mollusks; Mytilus - drug effects; Mytilus - enzymology; Mytilus - microbiology; Mytilus coruscus; Nucleotide sequence; Organisms; Oxidative stress; Oxidative Stress - drug effects; Oxidative Stress - genetics; Oxygen; Pathogenic bacteria; PCR; Phylogeny; Pollution; Pollution detection; Reactive oxygen species; Shellfish; Studies; Time dependence; Vibrio - pathogenicity; Water Pollution - analysis; Waterborne diseases
• ISSN: 0025-326X; 1879-3363
• DOI: 10.1016/j.marpolbul.2018.01.003

Bivalves use anti-oxidative enzyme systems to defend themselves against excessive reactive oxygen species, which are often catalyzed by environmental pollution. As a key member of anti-oxidative enzyme family, catalase plays a crucial role in scavenging the high level of reactive oxygen species to protect organisms against various oxidative stresses. In this study, a catalase homologue was identified from Mytilus coruscus (named McCAT, KX957929). The open reading frame of McCAT was 1844bp with a 5′ untranslated region of 341bp and a 3′ untranslated region of 927bp. The deduced amino acid sequence was 512 residues in length with theoretical pI/MW 8.02/57.91kDa. BLASTn and phylogenetic analyses strongly suggested that it was a member of catalase, also known as CAT family for its conserved catalytic site motif and proximal heme-ligand signature motif. Real-time fluorescence quantitative PCR showed that constitutive expression of McCAT was occurred, with increasing order in mantle, adductor, gill, hemocyte, gonad and hepatopancreas. It was observed that bacterial infection and heavy metals stimulation up-regulated McCAT mRNA expression in hepatopancreas with time-dependent manners. The maximum expression appeared at 8h after pathogenic bacteria injecting, with 15-fold in Vibrio parahemolyticus and 60-fold in Aeromonas hydrophila than that of 0h. The highest point of McCAT mRNA appeared at different times for exposure to heavy metals with copper at day 5 (0.1mg/L 30-fold, 0.5mg/L 15-fold, 1.5mg/L 6-fold) and plumbum at day 3 (3.0mg/L 20-fold). The enzymatic activity analysis found that McCAT activity in the gill of M. coruscus was affected by heavy metals concentration. The results suggested that McCAT plays a significant role in antioxidation and the expression of McCAT can be used as a biomarker for detection of marine environmental pollution. •A novel catalase (McCAT) was identified from Mytilus coruscus.•McCAT significantly affected by bacterial infection for immune defense.•McCAT mRNA was obviously up-regulated under stress of heavy metals.•McCAT might be an ideal marine pollution indicator.