|
3A - Biomarker/Biomonitoring (TUP/173) Hepatic metallothionein in deep-sea fishes from hydrothermal vents. Bebianno, Maria João1, Felícia, Helena1, 1 University of Algarve, Campus de Gambelas, F.C.M.A., Faro, Algarve, Portugal ABSTRACT- Hydrothermal vents are characterized by their extreme environment, like high temperature, high sulphide content and heavy metals. Despite the high levels of toxicity in the vent fluids, a large number of bathyal fish species have been caught in these areas. Tolerance of these organisms to such conditions is not known and may include several detoxification processes, like binding of metals to metalloproteins (metallothioneins). These proteins play a protective role against the toxic effect of heavy metals by sequestering and reducing the free metal ions present in organisms. This work intended to investigate metallothionein levels in fish livers from two species of bathyal fishes, common mora (Mora moro) and birdbeak dogfish (Deania calcea) from Menez Gwen hydrothermal vent (37°51′N) in the Mid-Atlantic Ridge. Samples were caught between 890 and 942 m depth in July 2001. Metallothionein was analysed by Differential Pulse Polarography in the liver according to Bebianno & Langston (1989). Total protein levels were analysed according to Lowry et al. (1951). Metallothionein concentrations were 6,9 ± 1,3 mg g-1 w. w. in M. moro and 418,2 ± 78,9 Key words: hydrothermal vents, Metallothionein, teleosts, elasmobranchs |
g g-1 w. w. in D. calcea. Total protein concentrations were 43,3 ± 3,1 mg g-1 w. w. in M. moro and 9,9 ± 2,7 mg g-1 w. w. in D. calcea. The metallothionein and total protein concentrations from M. moro were significantly higher than those from D. calcea. Proportion of proteins involved in detoxification processes in this tissue were significantly higher in M. moro than in D. calcea. This can reflect differences between species. Since marine teleosts (M. moro) have different osmoregulatory strategy from marine elasmobranchs (D. calcea), might occur differences in toxic mechanism and sensitivity and consequently in detoxification processes.