Nickel toxicity in the hindgut of an isopod Porcellio scaber (Oniscidea)

Studies on toxic effects of nickel were conducted in a chronic experiment on four groups of woodlice Porcellio scaber kept for 24 weeks on dry maple leaves containing Ni 0.1 (control), 8 (Ni1), 75 (Ni2) and 270 (Ni3) μg g−1 dry weight. Micro-PIXE elemental mapping complemented by proton backscattering was used to study relations between Ni and other elements in the hindgut. Data processed with GeoPIXE II demonstrated the highest amount of Ni in the hindgut of (Ni2) woodlice followed by the highest levels of Ca, Mn and Fe. Inverse relationship was observed between hindgut concentration of Zn and the Ni levels in the diet. Transmission electron microscopy (TEM) was used for checking possible relations between the ultrastructure of the hindgut epithelial cells and nickel tissue burden. In animals from all the “nickel groups” a series of ultrastructural alterations (disturbances in apical and basal membrane labyrinth and presence of lysosome-like structures with electron-dense material in the cytoplasm) was identified when compared with control woodlice. Large mitochondria with distinctly visible electron-dense precipitations inside them were present in the cells of animals from groups (Ni1) and (Ni3). In addition, a disturbed internal mitochondrial membrane system was observed in the cells of the (Ni2) woodlice group.