title: Tolerance to cadmium and cadmium-binding ligands in Great Salt Lake brine shrimp (Artemia salina).
abstract: Information on the accumulation of cadmium in cytosolic proteins of Great Lake brine shrimp (Artemia salina) was obtained from animals collected directly from the lake and also from animal hatched and maintained in three sublethal concentrations of cadmium (0.5, 2.0, 5.0 ppm) in saltwater aquaria. Brine shrimp growth under these conditions was monitored by measuring body lengths during a 7-day exposure period. Heat-stable, cadmium-binding ligands were isolated and identified by Sephadex G-75 chromatography and atomic absorption spectrophotometry. Cadmium was found to be equally distributed between high and low molecular weight proteins in animals collected from the lake and the 0.5 ppm cadmium group. There was also a slight growth stimulation noted in the 0.5-pm group. Higher cadmium incorporation was noted in low molecular weight fractions with increasing cadmium concentration in the exposure media. Low molecular weight fractions were also found to have high uv absorption characteristics at 250 nm and low absorption at 280 nm. Molecular weight of the cadmium-binding ligands was found to be 11,000 as estimated by the gel filtration method. De novo synthesis of this protein was increased as a function of cadmium concentration in the media. However, slow accumulation of cadmium in other protein fractions was also noticed in higher cadmium exposure groups, suggesting the existence of possible tolerance mechanisms in brine shrimp exposed to suspected acute cadmium concentrations.
mesh_terms: D000818:Animals; D001156:Artemia / Q000378:metabolism*; D002104:Cadmium / Q000633:toxicity*; D003600:Cytosol / Q000378:metabolism; D007700:Kinetics; D008668:Metallothionein / Q000302:isolation & purification / Q000378:metabolism*; D008970:Molecular Weight; D013347:Subcellular Fractions / Q000378:metabolism; D014873:Water Pollutants / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D014873:Water Pollutants; D014874:Water Pollutants, Chemical; C004203:cadmium-binding protein; D002104:Cadmium; D008668:Metallothionein