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

The literature on metallothioneins (MT) and metallothionein-like proteins (MTLP) in aquatic invertebrates is large and arkers uatic apparent etals Cd, ecific, MTs xcess rent logical increasing, and yet inconsistencies and confusion remain, not least over the physiological role of MT and their use as biom in environmental monitoring programmes. We have collated published information on MT in three important groups of aq invertebrates—the molluscs, crustaceans and annelid worms, and attempted to seek explanations for some of the inconsistencies present in the dataset. MTs can be induced by the essential metals Cu and Zn and the non-essential m Ag and Hg in both vertebrates and invertebrates, but their induction is variable. Such variation is intraspecific and intersp and is down to a variety of reasons environmental and physiological explored here. Against this background of variability do appear to play roles both in the routine metabolic handling of essential Cu and Zn, but also in the detoxification of e amounts intracellularly of these metals and of non-essential Cd, Ag and Hg. Different isoforms of MT probably play diffe physiological roles, and the dependence on MT in detoxification processes varies environmentally and between zoo groups. MTs can be used as biomarkers if used wisely in well-designed environmental monitoring programmes. © 2005 Elsevier B.V. All rights reserved.