engleski

Cadmium accumulation and Cd-binding proteins in marine invertebrates

Tissue and subcellular accumulation of cadmium in different tissues of the three marine invertebrates: the bivalve Mytilus edulis, the tunicate Ciona intestinalis and the echinoderm Asterias rubens were determined using radioactive Cd tracer. Animals were exposed for 21 days to 0.05, 2 and 50 ug Cd/l containing 3.2 uCi/l Cd-109. Quantitative data were obtained by dissecting, weighing and subsequently measuring radioactivity in organs and tissues. Selected tissues from exposed animals and fractionated to obtain mitochondrial/nuclear fraction (P1), a microsomal fraction (P2) and cytosolic fraction (S50). Quantitative data were obtained by counting gamma-emission in these fractions. An aliquot of the S50 fraction from each tissue and exposure group was heated at 85C for 10 minutes to obtain a fraction enriched in metallothionein-like proteins, which were quantified by differential pulse polarography. Differences between each exposure and each tissue with regard to the amount of radioactivity and MT content in each tissue were tested. The highest concentrations of Cd at all exposure treatments were found in hepatopancreas and body wall in M. edulis and A. rubens, respectively. Taking into account all treatments, Cd accumulation in tunic of C. intestinalis was relatively high. Over 70% of Cd were present in S50 fraction at all exposures in all studied species. The MT levels were increased at the highest Cd-exposure in all studied species/tissues.

cadmium accumulaton; marine invertebrates

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