Identifying the mechanisms by which non-essential metals and excess amounts of essential metals adversely affect crustacean biochemistry, physiology, and behaviour forms part of this work, as does study the mechanisms crustaceans use to detoxify trace metals, for example metallothionein synthesis. Quantification of metallothioneins is one such biomarker the group is currently investigating. Another application is in protecting the health of human populations, which may be consuming various amounts of these trace metals depending on the contribution of seafood to their diet. Role of Metallothioneins Henrik Holbech programming the dilution robot. Metallothioneins are a family of metals binding proteins which play an important role in the internal handling of trace metals, notably the non-essential metal cadmium.
Inorganic arsenic is known to be toxic, whereas arsenobetaine has been shown to be innocuous.
The toxicity of arsenosugars is yet to be determined. Kevin Francesconi and several masters students are studying the occurrence of these forms in sea water and sediment, and their bioavailability, and the form in which they are accumulated in macroalgae and herbivorous, detritivorous, and carnivorous marine animals. The chemical structures, bioavailabilty, and retention of certain arsenic compounds notably, arsenobetaine and related organoarsenic compounds, suggests they may play a role in osmoregulation and other biological functions in aquatic marine organisms. It has recently been proposed that chemicals with oestrogen-like activity may interfere with proper sexual development in human and wildlife. The production of vitellogenin by fish is under oestrogenic control, with the result that the normally very low concentrations of oestrogen in male fish preclude its synthesis.