Effects of copper on the latency of lysosomal hexosaminidase in the digestive cells of Mytilus edulis

Mytilus edulis collected from Tomales Bay, California, USA, during mid-winter 1979 were exposed to increased concentrations of dissolved copper under controlled laboratory conditions. A dose-dependent reduction in the latency of lysosomal hexosaminidase activity in digestive cells was induced after a 30 d exposure to copper. The half-time of the hexosaminidase staining reaction in sections of digestive gland from control mussels was 15.5 min; for mussels exposed to 25, 50, and 75 mu g Cu l super(-1) it was 11.8, 8.5, and 5.5 min, respectively. In addition, the dye-coupled reaction product was seen earlier in sections from individuals exposed to 50 and 75 mu g Cu l super(-1) (after 30 s) and 25 mu g Cu l super(-1) (1 min) than in sections from control individuals (2.5 min). Copper accumulations were demonstrated histochemically to have the same distribution as the hexosaminidase reaction product, indicating that copper is sequestered in lysosomes. Copper concentrations in digestive gland tissue were related to the concentrations of copper in the water to which the mussels were exposed.