Electrochemical Characterization of Metal-Binding Properties of Metallothioneins Isolated from M. galloprovincialis

Amperometric titrations of defined metallothionein concentrations with the standard CdCl2 solution have been performed in seawater samples at pH > 8, in order to define the metal-binding properties of purified mussel metallothionein component. The concentration of the formed Cd-thionein complex has been assessed in the indirect and direct mode. The results on the available ligand concentration CL for complexing Cd2+ ions and the apparent stability constant K, determined by two procedures are compared and the differences discussed. Complexing characteristics of the metallothionein can be reliably determined only if the evaluation is based on the specific signal of Cd-thionein complex

Prihvatljivost ciljanog organa (probavne žlijezde) dagnje za provođenje biomonitoringa

In coastal marine areas, the level of metallothioneins (MTs) is monitored as the specific response to trace heavy metals and is considered as a biomarker of metal exposure. Laboratory experiments with bivalves indicate that MT synthesis is induced by Cd, Cu, Hg, Ag and Zn ions. The results of our study, conducted with the mussel Mytilus galloprovincialis, deployed 12 months in the "hot spot" area of the Kaštela Bay, Dalmatia, Croatia, are evaluated considering the recommendation of MED POL Programme for estimating exposure of mussels to trace heavy metals by means of MTs. Our data clearly indicate that the MT level in the digestive gland of the Mediterranean mussel depends on the biotic and abiotic parameters. Beside MT level, a number of parameters, like digestive gland mass, shell mass, cytosolic metal concentration is needed in order to define if MT level in the digestive gland of mussels is indicative as a biomarker of cadmium exposure.U priobalnim morskim područjima razina metalotioneina (MT) prati se kao specifični odgovor na teške metale u tragovima te se smatra biomarkerom izloženosti metalima. Laboratorijski eksperimenti sa školjkama pokazuju da sintezu MT induciraju ioni Cd, Cu, Hg, Ag i Zn. Rezultati našeg istraživanja, koje je provedeno s dagnjama, Mytilus galloprovincialis, izloženim tijekom 12 mjeseci u području "vrućih točaka" u Kaštelanskom zaljevu, Dalmacija, Hrvatska, razmatrani su u skladu s preporukama MED POL programa za procjenu izloženosti dagnja teškim metalima u tragovima putem MT. Naši podaci jasno ukazuju da razina MT u probavnoj žlijezdi mediteranske dagnje ovisi o biotičkim i abiotičkim parametrima. Osim razine MT, potrebni su brojni parametri, poput mase probavne žlijezde, mase ljušture te koncentracije metala u citosolu kako bi se moglo definirati da li razina MT u probavnoj žlijezdi dagnja upućuje na njihovu izloženost kadmiju