In vivo and in vitro effects of heavy metals on DNA polymerase activities in the digestive gland of Mytilus galloprovincialis Lam

1. 1. The in vivo and in vitro effects of heavy metals on DNA polymerase activity in the isolated nuclei and in cellular salt extracts from the digestive gland of the marine invertebrate Mytilus galloprovincialis Lam. have been studied. 2. 2. The DNA repair activity in the isolated nuclei from the animals previously exposed to sublethal concentrations of Cu²⁺ or Hg²⁺ is not affected by the significant accumulation of metal cations. 3. 3. DNA polymerases α and β activities in the cellular salt extracts are both stimulated in the animals exposed to Hg²⁺, but not to Cu²⁺. 4. 4. Cu²⁺, Hg²⁺, Zn²⁺ and Cd²⁺, when directly added to the reaction mixtures for the DNA polymerase assays, inhibit the enzyme activities only at very high concentrations in the isolated nuclei as well as in the cellular salt extracts from control animals. 5. 5. The results are in line with the capability of the molluscs of adapting to the accumulation of heavy metals.