First data on the effect of Aluminium intake in Chamelea gallina of exploited stocks in the Southern Adriatic Sea (Central Mediterranean Sea)

Abstract

The striped venus clam Chamelea gallina is an important shellfish resource in coastal area of Mediterranean Basin, playing a fundamental role in the ecosystems. In the last two decades there has been a reduction in the stocks of this bivalve with several mortality events along Adriatic Sea due to pollutants. Aiming to evaluate the effects on clams of the anthropogenic increase of some metals in the sea, we focused on aluminium. In particular, we tested whether Al could affect mucus secretion, since mucins are involved in protection from pathogens and toxicants and transport of alimentary particles and pseudofeces. Aluminium was administered in the form of aluminium chloride at concentrations of 25, 50 and 200 μM. Histochemical and lectin-histochemical - analyses were used to evaluate in situ qualitative and quantitative variation of the muciparous secretions produced by both the gills and foot epithelia. Treatments resulted in quali-quantitative alterations in the secretions of both gills and foot epithelia, in particular reduction of glycosylation resulting in a general decrease of acidic residuals and of mannosylated, glycosaminylated and fucosylated chains. This can result in a decrease of acidity and viscosity of mucus and thus it could affect its functionality and the survival of the animals.