title: Toxicological responses of the hard clam Meretrix meretrix exposed to excess dissolved iron or challenged by Vibrio parahaemolyticus.
abstract: The responses of genes encoding defense components such as ferritin, the lipopolysaccharide-induced tumor necrosis factor-alpha factor (LITAF), the inhibitor of nuclear factor-κB (IκB), metallothionein, and glutathione peroxidase were assessed at the transcriptional level in order to investigate the toxicological and immune mechanism of the hard clam Meretrix meretrix (HCMM) following challenge with iron or a bacterium (Vibrio parahaemolyticus). Fe dissolved in natural seawater led to an increase of Fe content in both the hepatopancreas and gill tissue of HCMM between 4 and 15 days of exposure. The ferritin gene responded both transcriptionally as indicated by real-time quantitative PCR and translationally as shown by western blotting results to iron exposure and both transcriptional and translational ferritin expression in the hepatopancreas had a positive correlation with the concentration of dissolved iron in seawater. Both iron and V. parahaemolyticus exposure triggered immune responses with similar trends in clam tissues. There was a significant post-challenge mRNA expression of LITAF and IκB at 3h, ferritin at 24h, and metallothionein and glutathione peroxidase at 48h. This behavior might be linked to their specific functions in physiological processes. These results suggested that similar signaling pathways were triggered during both iron and V. parahaemolyticus challenges. Here, we indicated that the ferritin of Meretrix meretrix was an intermediate in the pathway of iron homeostasis and in its innate immune defense mechanism.
authors.affiliation: State Key Laboratory of Stress Cell Biology, School of Life Science, Xiamen University, Xiamen 361102, China; State Key Laboratory of Marine Environmental Science, School of Ocean and Earth Science, Xiamen University, Xiamen 361102, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: Department of Chemistry, College of Chemistry & Chemical Engineering, and the Key Laboratory of Chemical Biology of Fujian Province, Xiamen University, Xiamen 361102, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Stress Cell Biology, School of Life Science, Xiamen University, Xiamen 361102, China.
authors.forename: Hui-Fang
authors.initials: HF
authors.lastname: Peng
authors.affiliation: State Key Laboratory of Marine Environmental Science, School of Ocean and Earth Science, Xiamen University, Xiamen 361102, China. Electronic address: chke@xmu.edu.cn.
authors.forename: Cai-Huan
authors.initials: CH
authors.lastname: Ke
authors.affiliation: State Key Laboratory of Stress Cell Biology, School of Life Science, Xiamen University, Xiamen 361102, China; State Key Laboratory of Marine Environmental Science, School of Ocean and Earth Science, Xiamen University, Xiamen 361102, China; Department of Chemistry, College of Chemistry & Chemical Engineering, and the Key Laboratory of Chemical Biology of Fujian Province, Xiamen University, Xiamen 361102, China. Electronic address: hqhuang@xmu.edu.cn.
authors.forename: He-Qing
authors.initials: HQ
authors.lastname: Huang
mesh_terms: D000818:Animals; D049872:Bivalvia / Q000187:drug effects* / Q000382:microbiology*; D005786:Gene Expression Regulation / Q000187:drug effects; D005880:Gills / Q000187:drug effects; D043143:Hepatopancreas / Q000187:drug effects; D007113:Immunity, Innate / Q000235:genetics; D007501:Iron / Q000633:toxicity*; D014736:Vibrio parahaemolyticus / Q000502:physiology*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D014874:Water Pollutants, Chemical; D007501:Iron
keywords: Ferritin; Immune defense mechanism; Iron; Iron homeostasis; Oxidative stress