Transcriptional response of lysozyme, metallothionein, and superoxide dismutase to combined exposure to heavy metals and bacteria in Mactra veneriformis

• Published in: Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology
• Main Authors: Fang, Yan, Yang, Hongsheng, Liu, Baozhong, Zhang, Libing, Yang, HS
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2013
• Subjects: Clam; Mollusk; Lysozyme; Metallothionein; Superoxide Dismutase; Heavy Metals; Bacteria; Mactra Veneriformis; Biochemistry & Molecular Biology; Endocrinology & Metabolism; Toxicology; Zoology; Science & Technology; Life Sciences & Biomedicine; OYSTER CRASSOSTREA-VIRGINICA; PACIFIC OYSTER; MESSENGER-RNA; MYTILUS-GALLOPROVINCIALIS; MEDITERRANEAN MUSSEL; DREISSENA-POLYMORPHA; CERASTODERMA-EDULE; CADMIUM EXPOSURE; GENE-EXPRESSION; CDNA CLONING; Pacific; Pacific oyster
• Online Access: http://ir.qdio.ac.cn/handle/337002/16502; https://doi.org/10.1016/j.cbpc.2012.10.002

The response of the defense components lysozyme (LYZ), metallothionein (MT), and superoxide dismutase (SOD) to combined exposure to heavy metals and bacteria was assessed at transcriptional level in the surf clam Mactra veneriformis. First, the full-length LYZ cDNA containing 808 nucleotides and encoding 194 deduced amino acids was identified from the clam. Multiple alignments revealed that MvLYZ had a high identity with invertebrate-type LYZs from other mollusks. Next, clams were exposed to Vibrio parahaemolyticus and a mixture of cadmium and mercury, alone or in combination, for 7 days. Cumulative mortality of clams and mRNA expressions of the three defense components were analyzed. The highest cumulative mortality took place in the combined treatment on day 7. The expression of the three genes was up-regulated in response to treatments compared to the control with different response times and transcriptional levels; the response to combined exposure occurred earlier than to single exposure. Among the experimental groups. MvLYZ expression and MvSOD expression peaked in the combined treatment on day 3, whereas MvMT expression peaked in heavy metals treatment on day 5. Furthermore, interactive effects of heavy metals and Vibrio on transcriptional response changed over the exposure time. Therefore, transcriptional regulation of the three genes under combined exposure was more complex than under single exposure. (C) 2012 Elsevier Inc. All rights reserved. The response of the defense components lysozyme (LYZ), metallothionein (MT), and superoxide dismutase (SOD) to combined exposure to heavy metals and bacteria was assessed at transcriptional level in the surf clam Mactra veneriformis. First, the full-length LYZ cDNA containing 808 nucleotides and encoding 194 deduced amino acids was identified from the clam. Multiple alignments revealed that MvLYZ had a high identity with invertebrate-type LYZs from other mollusks. Next, clams were exposed to Vibrio parahaemolyticus and a mixture of cadmium and mercury, alone or ...