6533b82cfe1ef96bd128ea62

RESEARCH PRODUCT

Effect of cadmium pre-exposure in cadmium accumulation by brine shrimp Artemia: Involvement of low-molecular-weight cadmium-binding ligands

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Abstract Cadmium is a ubiquitous non-essential element that possesses high toxicity and is easily accumulated from the environment by aquatic organisms. It is known that pre-exposure to cadmium increases the resistance of animals to a subsequent exposure. In this work, we report studies of the effect of pre-exposure to cadmium on the accumulation of this metal from seawater by brine shrimp Artemia, as well as the involvement of low-molecular-weight cadmium-binding ligands in this process. During the pre-exposure experiments, animals were kept in seawater containing 20 mg/litre Cd for 24 h and then transferred to clean seawater for 48 h. Afterwards, pre-exposed and control animals were exposed to 10 mg/litre Cd for 14 days. Samples from both groups were taken at different times. Heat-stable cadmium-binding ligands were isolated by Sephadex G-75 chromatography. On the first and third days of exposure, higher levels of cadmium were found in pre-exposed animals than in the non-pre-exposed, but, after six days, there were no differences in cadmium content between these groups. Differences in the chromatographic profile of cadmium-binding ligands were found between both experimental groups at the beginning of the exposure experiment, but, after three days, exposure chromatographic profiles were similar for both groups. Our results show that cadmium pre-exposure modifies the cadmium-accumulation rate temporarily but has no effect on the cadmium-saturation level.