Anaerobiosis and metabolic plasticity of Pinna nobilis: Biochemical and ecological features.

Changes in the energetic metabolism were studied in the fan mussel Pinna nobilis L. exposed to environmental and anthropic stress. The high polymorphism of enzymes suggests an adaptation of the fan mussel to environmental variability peculiar of transitional waters with respect to the same species living in exposed coastal sea. The electrophoretic patterns showed a predominance of LDH-A4 and the presence of both mitochondrial and cytosolic MDH isozymes. Moreover, in all the analyzed tissues and organs, MDH activity was greater than the LDH one. Metabolic plasticity of the fan mussel is further highlighted by octopine dehydrogenase and superoxide dismutase electrophoretic patterns, showing the presence of many isoforms. These evidences are also confirmed by spectroscopic determinations of alanopine, tauropine, strombine and octopine dehydrogenase activity characterized by a specific trend due to environmental variability. Specific variations in anaerobic capacity of P. nobilis L. are discussed in relation to their distribution according to the marine-brackish gradient. [ABSTRACT FROM AUTHOR]