The effects of hypomagnetic conditions and the reversal of the geomagnetic field (GMF) on intracellular Ca2+-dependent proteases (calpains) of fish and invertebrates have been studied in vivo and in...

Results of studies presented in recent papers and personal data related to investigation of structure, classification, phylogeny of calcium-dependent peptidases or calpains have been analyzed. The most extensively studied functions of calpains in cell activity have been examined. Some not yet resolved questions concerned with the biological role of a great number of proteins of the calpain family have been defined.

The heart rate and calpain activity of blue mussels Mytilus edulis from the sublittoral zone, exposed to different levels of water-borne copper and cadmium, was investigated in a long-term experiment. The content of cadmium and copper in the blue mussel was determined using flame and graphite Atomic absorption spectroscopy. The observed concentrations ranged from 2.5 to 89.1 μg/g dry weight for cadmium and from 6.1 to 51.0 μg/g dry weight for copper in the control and highest concentration, respectively. Initially, increase in cardiac activity in response to copper and Cadmium exposure was observed under all pollutant concentrations (5–250 and 10–500 μg/L, respectively). The calpain-like activity in gills and hepatopancreas of the mussels treated with metals changed in dose- and time-dependent manner: from a sharp rise at the 250 μg/L concentration of copper on the first day to a significant decrease under the effect of Cadmium in the concentration of 500 μg/L on the third day of the experiment. These results suggest that: (i) heart rate oscillation may reflect active adaptation of blue mussels to contamination and (ii) animals have different sensitivity to copper and Cadmium according to the role of the metals in the mussels’ life activity.