Seasonal differences of lysosomal, lipid and lipofuscin parameters in the digestive gland of the mussel Mytilus galloprovincialis

摘要

The aim of the present study was to provide additional information regarding the seasonal influence on structural parameters of the lysosomal system, as well as on the variation of lipids and lipofuscins, in the digestive gland of mussels Mytilus galloprovincialis, and thus to define the most suitable time for performing sampling procedures in biomonitoring studies. The parallel examination of these biological parameters indicated that in early summer there was a very active lysosomal system together with extremely limited lipofuscin inclusions and moderate amount of lipids in the digestive gland of mussels. In early winter, the lysosomal system was restricted, and at the same time raised lipofuscin content and reduced amount of lipids occurred. In early spring, lysosomes became active again and concurrently high lipofuscin material was detected, whereas lipids showed an increase relative to winter. The results lead to the conclusion that summer represents the most appropriate period for sampling in biomonitoring studies dealing with digestive gland parameters, at least in mussels from Thermaikos Gulf and possibly from the Mediterranean Sea in general. In addition, the relationship between the N-acetyl-β-hexosaminidase reaction and the presence of lipids in digestive gland lysosomes of mussels is discussed.