TOPOISOMERASE ACTIVITY IN ASTACUS LEPTODACTYLUS: EFFECT OF TEMPERATURE AND WATER POLLUTION

DNA topoisomerases are enzymes able to modify the DNA structure making it accessible for replication and transcription. When a cell lacks DNA topoisomerase activity the DNA becomes inaccessible to other enzymes that control critical cell functions. Studies point out that exposure to stressors, such as heat, results in modifications of DNA structure by impairing DNA topoisomerase activity. Since crayfish are exposed to various stress factors in their natural environment, among which temperature and pollution are the most common, we have evaluated the topoisomerase activity in different organs of Astacus leptodactylus kept at different temperatures and exposed to polluted water. DNA topoisomerase activity was evaluated in the hepatopancreas, muscle tissue and spermiducts of crayfish kept at 4°C, 15°C and 25°C. Topoisomerase activity was detected in the hepatopancreas at the all three temperatures and in the spemiduct at 15°C, but was not present in the muscle tissue. When kept in polluted water, Astacus leptodactylus survived well and DNA topoisomerase activity in the hepatopancreas not only remained unchanged but increased after a week of recovery in non polluted water. Taken together these data indicate that topoisomerase activity can be a useful marker for crayfish viability.