Metallothioneins in aquatic invertebrates: Their role in metal detoxification and their use as biomarkers

• Published in: Aquatic toxicology Vol. 76; no. 2; pp. 160 - 202
• Main Authors: Amiard, J.-C., Amiard-Triquet, C., Barka, S., Pellerin, J., Rainbow, P.S.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 10-02-2006; Elsevier Science
• Subjects: Animal Structures - chemistry; Animal, plant and microbial ecology; Animals; Annelida; Applied ecology; Aquatic invertebrates; bioaccumulation; Biological and medical sciences; Biomarker; Biomarkers; cadmium; copper; Crustacea; Detoxification; Ecotoxicology, biological effects of pollution; Environmental Exposure; Environmental Monitoring - methods; Fundamental and applied biological sciences. Psychology; General aspects; heavy metals; Invertebrata; Invertebrates - chemistry; Invertebrates - metabolism; literature reviews; Marine; mercury; metabolic detoxification; Metallothionein; Metallothionein - genetics; Metallothionein - metabolism; Metallothionein - physiology; Metals - analysis; Metals - toxicity; Mollusca; molluscs; protein induction; Review; silver; Species Specificity; Time Factors; water pollution; zinc; Biomarker; Aquatic invertebrates; Review; Metallothionein; Detoxification; Aquatic environment; Ecotoxicology; Biological marker; Metal; Invertebrata; Metalloproteins
• ISSN: 0166-445X; 1879-1514
• DOI: 10.1016/j.aquatox.2005.08.015

The literature on metallothioneins (MT) and metallothionein-like proteins (MTLP) in aquatic invertebrates is large and increasing, and yet inconsistencies and confusion remain, not least over the physiological role of MT and their use as biomarkers in environmental monitoring programmes. We have collated published information on MT in three important groups of aquatic invertebrates—the molluscs, crustaceans and annelid worms, and attempted to seek explanations for some of the apparent inconsistencies present in the dataset. MTs can be induced by the essential metals Cu and Zn and the non-essential metals Cd, Ag and Hg in both vertebrates and invertebrates, but their induction is variable. Such variation is intraspecific and interspecific, and is down to a variety of reasons environmental and physiological explored here. Against this background of variability MTs do appear to play roles both in the routine metabolic handling of essential Cu and Zn, but also in the detoxification of excess amounts intracellularly of these metals and of non-essential Cd, Ag and Hg. Different isoforms of MT probably play different physiological roles, and the dependence on MT in detoxification processes varies environmentally and between zoological groups. MTs can be used as biomarkers if used wisely in well-designed environmental monitoring programmes.