Effect of ambient oxygen concentration on lipofuscin accumulation in a clam Sunetta scripta and a mussel Perna viridis

Lipofuscin accumulation can be considered as a physiological index of oxygen stress at the cellular level. In clam Sunetta scripta and mussel Perna viridis a definite correlation between the degree of lipofuscin accumulation and hypoxic exposure time was noticed. With the advancement of hypoxic exposure time, an increment in both lipofuscin accumulation in the hepatopancreatic tissues and carotenoid concentration in the whole tissue has been observed in both the species. The elevation in carotenoid concentration is more prominent in P.viridis rather than in S.scripta. A close similarity was observed between hypoxic exposed and copper (sublethal) exposed animals regarding the lipofuscin accumulation and total carotenoid concentration. In the case of P.viridis, the increase in the total carotenoid concentration at 48 h of hypoxic exposure and 48 h of heavy metal exposure was found to be nearly 87% and 95% higher than that of the control respectively. Whereas in S.scripta, the increase at 48 h of hypoxic and heavy metal exposed animals were found to be nearly 40% higher than that of the control.