Lysosomal,tissue and cellular alterations in the gills,palps and intestine of the mussels Mytilus galloprovincialis,in relation to pollution

Lysosomal, tissue and cellular alterations of the gill, the palp and the intestine epithelium of the mussel Mytilus galloprovincialis (L.) collected from six stations along a closed estuarine system (Thermaikos Gulf, northern Greece) were monitored in May, August and December. Semi-quantitative evaluation of histopathological alterations was performed under the light microscope, while certain of the latter alterations were confirmed electron microscopically. In addition, morphometrical evaluation of the volume density of the lysosomes under the electron microscope was conducted. The observed alterations, as the detachment of gill epithelial cells from the basement membranes and the dilated extracellular spaces formed either between the lateral plasma membranes or between the infoldings of the basal plasma membrane in the palps and the intestine are possibly related to the degree of pollution at the examined stations. The particularly expanded extracellular spaces formed by basal plasma membrane infoldings in the intestine in spring may be attributable to red tide algal infection. On the other hand, differences in morphometric parameters of lysosomal structures indicated no direct relationships with pollution levels.Communicated by O. Kinne, Oldendorf/Luhe