Comparison of cadmium-binding protein induction among mayfly larvae of heavy metal resistant (Baetis thermicus) and susceptible species (B. yoshinensis and B. sahoensis)

Abstract

1. The mayfly larvae of a heavy metal resistant species ( Baetis thermicus) and two heavy metal susceptible species ( B. yoshinensis and B. sahoensis) were exposed to cadmium at a concentration of 10 μg/1 and the comparative induction of cadmium-binding protein was correlated to their susceptibility to the metal. 2. Amounts of cadmium accumulated in the larvae were increased linearly depending on the duration of exposure. However, there was little difference in the cadmium concentration in each species. 3. Cadmium-binding protein was induced only in the larvae of resistant species ( B. thermicus). 4. Copper and zinc concentrations in the two susceptible larvae were decreased by cadmium exposure, while zinc but not copper concentrations were increased in the resistant larvae.