Adenylate Energy Charge As A Tool For Evaluating Sub-Lethal Toxicity

Abstract

Adenylate energy charge (AEC) is directly related to the cellular concentrations of the three adenylates nucleotides ATP, ADP and AMP. This biochemical index reaches high values (0.9) under optimal conditions but drops rapidly in the presence of stressing agents. In vertebrates, AEC is strongly regulated and maintained within narrow limits. In contrast, in invertebrates, AEC displays a wide range of values according to the importance of the internal stress or to the variations in the external environment of the organisms (natural or anthropogenic). This work concerns the use of adenine nucleotides concentrations, ATP/ADP ratios and AEC as physiological markers in different species. Our results show that AEC is modified in animals submitted to experimental pollution or sampled in polluted areas. Results of zinc contamination in adults of clam Ruditapes decussatus show that after one month exposure, AEC values change significantly. The use of AEC in the bivalve Ruditapes decussatus for in situ evaluation allowed a classification among different sampling sites in what concerns environmental quality. In this way, AEC proved to be an accurate biochemical and physiological marker in monitoring the health of organisms exposed to pollution and can be used as a complementary tool in impact and environmental management studies.