title: Cadmium accumulation and Cd-binding proteins in marine invertebrates--a radiotracer study.
abstract: Tissue and subcellular accumulation of cadmium were studied in different tissues of three marine invertebrates (blue mussel Mytilus edulis, the tunicate Ciona intestinalis and the sea star Asterias rubens) using radioactive 109Cd as a tracer. The organisms were exposed to 0.05, 2 and 50 microg Cd l(-1) for 21 days. Quantitative data were obtained by dissecting, weighing and subsequently measuring radioactivity in organs and tissues. Differences between each exposure and each tissue with regard to the amount of radioactivity and metallothionein (MT) content were evaluated. Obvious interspecies differences in Cd accumulation were observed, as well as differences between tissues of the three species. The highest concentrations of Cd in all exposure treatments were found in the hepatopancreas of M. edulis and body wall of A. rubens. Taking all treatments into account, Cd accumulation in the tunic of C. intestinalis was high compared to other tissues from this species. Over 60% of Cd was present in the S50 fraction in all treatments in all three species. Metallothionein levels were increased at the highest Cd-exposure in all species and tissues, except in branchial pharynx of C. intestinalis where the highest MT level was reached following exposure to 2 microg Cd l(-1). The most surprising finding was that even the lowest Cd exposure concentration (0.05 microg Cd l(-1)) caused MT induction in pyloric caeca of A. rubens, but there was no dose-dependent increase in MT at higher exposure levels.
authors.affiliation: Ruder Bosković Institute, Center for Marine and Environmental Research, P.O. Box 180, Bijenicka c. 54, HR-10002 Zagreb, Croatia. erk@irb.hr
authors.forename: Marijana
authors.initials: M
authors.lastname: Erk
authors.forename: Anders
authors.initials: A
authors.lastname: Ruus
authors.forename: Kristian
authors.initials: K
authors.lastname: Ingebrigtsen
authors.forename: Ketil
authors.initials: K
authors.lastname: Hylland
mesh_terms: D000818:Animals; D002104:Cadmium / Q000378:metabolism* / Q000633:toxicity; D002106:Cadmium Radioisotopes; D004305:Dose-Response Relationship, Drug; D007448:Invertebrates / Q000378:metabolism*; D008386:Marine Biology; D008668:Metallothionein / Q000032:analysis / Q000378:metabolism*; D013045:Species Specificity; D014018:Tissue Distribution / Q000187:drug effects; D014874:Water Pollutants, Chemical / Q000633:toxicity
chemical_list: D002106:Cadmium Radioisotopes; D014874:Water Pollutants, Chemical; C004203:cadmium-binding protein; D002104:Cadmium; D008668:Metallothionein