ISSN:
1432-0703
Source:
Springer Online Journal Archives 1860-2000
Topics:
Energy, Environment Protection, Nuclear Power Engineering
,
Medicine
Notes:
Abstract Individuals ofMurex trunculus from the Adriatic Sea were exposed to cadmium in the laboratory under chronic conditions (0.05 mg/L, up to 30 days). Cadmium contents in the soft parts of the snails increased considerably, the highest concentrations occurring in combined hepatopancreas + kidney tissues. However, high amounts of cadmium were also found in unexposed individuals. No significant changes were observed in the concentrations of zinc. Cytosolic fractions of hepatopancreas + kidney organs were separated by gel and ion exchange chromatography. Variable amounts of cadmium were associated with components with a molecular weight of more than 75000 Daltons. Most of the metal, however, was bound to a protein with an apparent molecular weight of 11000 Daltons. This protein showed low absorption at 280 and a higher one at 254 nm. Amino acid composition revealed high amounts of cysteine (26%), lack of tyrosine, but presence of phenylalanine (4%). On the basis of these features, the protein was identified as a metallothionein-like protein. With increasing time of exposure, cadmium replaced zinc from this protein, the latter metal moving towards fractions with a molecular weight of less than 3000 Daltons. Moreover, a “spillover” effect was observed:The cadmium content of the metallothionein-like protein increased up to a saturation point beyond which excess cadmium was bound to high molecular weight components.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01055022
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