Small cells in the midgut glands of terrestrial isopoda: Sites of heavy metal accumulation

Heavy metals in the terrestrial isopod Porcellio scaber latreille. I. Histochemical and ultrastructural characterization of metal-containing lysosomes

“…Frenzel (1884) called these cells S-cells. Prosi et al (1983) characterized them as epithelial cells exhibiting an apical microvillous border and a poorly developed basal labyrinth. They contain one or two irregularly shaped nuclei and, in contrast to large cells, the small ones contain little glycogen and lipid inclusions.…”

“…After fixation and chromation the hepatopancreas tubules were rinsed for 24 hours in distilled water, dehydrated and embedded in paraffin. Sections of 5/~m thickness were not poststained because of chromatic interference and for better visualization of the light yellow granules of precipitated lead chromate (Prosi et al, 1983). Copper was demonstrated by the method described by Wieser (1967).…”

Localization of metals in cells of saprophagous soil arthropods (Isopoda, Diplopoda, Collembola)

“…Also, nonessential elements can be accumulated, distributed, and compartmentalized because they (or their organic complexes) mimic essential elements and have similar chemical affinities (Morgan et al, 1995). Consequently, in specimens of terrestrial isopods from contaminated areas, zinc, cadmium, lead, and nickel have also been found in these type B granules (Hopkin and Martin, 1982a;Prosi et al, 1983; for the freshwater isopod, Asellus meridianus: Brown, 1978) which increase in number upon metal feeding (Hopkin, 1989;Köhler et al, 1996a). Regularly, about 80% of total body copper is stored in the type B granules of the hepatopancreatic S-cells in isopods, but the chemical character of these deposits is not precisely known for these animals.…”

“…The first evidence of the high copper content of these structures was given by means of rubeanic acid staining and X-ray spectrophotometry (Wieser, 1961). Due to their ultrastructure and high copper content, these granules were classified into the type B group but contain, in addition to copper, high amounts of calcium and sulfur (Wieser, 1968;Wieser and Klima, 1969;Alikhan, 1972;Hopkin and Martin, 1982a;Prosi et al, 1983;Marcaillou et al, 1986;Dallinger and Prosi, 1988;Prosi and Dallinger, 1988). Also, nonessential elements can be accumulated, distributed, and compartmentalized because they (or their organic complexes) mimic essential elements and have similar chemical affinities (Morgan et al, 1995).…”

The Influence of Zinc on the Uptake and Loss of Cadmium and Lead in the Woodlouse, Porcellio scaber (Isopoda, Oniscidea)

“…As far as is known heavy metals are stored mainly in the hepatopancreas. This organ consists of B and S cells in which the metals are not only bound to speci"c low-molecular-weight compounds in the cytosol but are also stored in an undissolved nontoxic form in vesicles of lysosomal origin (for further information see Martin, 1982b, 1984;Hopkin, 1989Hopkin, , 1990bProsi and Dallinger 1988;Prosi et al, 1983;Donker et al, 1990). Because B and S cells have di!erent functions, the storage of metals in either one or both of these cell types and the characteristics of the metals themselves are important for the ability of the animals to eliminate them again.…”