The composition of intracellular granules from the metal-accumulating cells of the common garden snail (Helix aspersa)

Abstract

Certain cells in the hepatopancreas of the common garden snail (Helix aspersa) contain intracellular granules that are sites of metal-ion accumulation. These granules have been extracted and investigated by u.v. and i.r. spectroscopy, atomic-absorption spectroscopy, X-ray microanalysis, thermogravimetric analysis, enzymic assay and microanalysis. The deposits contain about 18% (w/w) water, 5% (w/w) organic matter and 76% (w/w) inorganic material of which the main components are Ca2+, Mg2+ and P2O7(4)-. The possible origin of these granules is discussed, as is their role in detoxifying heavy-metal ions.

Implication of the Midgut of the CentipedeLithobius forficatusin the Heavy Metal Detoxification Process

“…These granules, concentrically structured, are usually composed of concentric layers of amorphous calcium and magnesium ortho-and pyrophosphate with a small organic component (Howard et al, 1981;Taylor et al, 1986). They can contain different metals such as zinc, manganese, potassium, and lead but cadmium, copper, and mercury have not been detected (Hopkin, 1989;Masson and Simkiss, 1982).…”

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

“…Type A granules usually consist of concentric layers of calcium and magnesium ortho-and pyrophosphates with less than 10% organic content (Howard et al, 1981;Taylor et al, 1986) but may also contain other metals from the Ia and IIa group of the periodic table of elements (class A metals, Nieboer and Richardson, 1980) plus some "borderline" metals (transition elements of the 4th period), e.g., zinc and manganese (Hopkin, 1989). In their typical shape type A granules have been detected, e.g., in the epithelial layers of the midgut resorptive tissue of Diplopoda and Collembola (Humbert, 1974(Humbert, , 1977(Humbert, , 1978(Humbert, , 1979van Straalen et al, 1987;Pawert et al, 1996).…”

Tachyzoite calcium changes during cell invasion by Toxoplasma gondii

“…The ®rst is the BG, which contains large amounts of P (48%) and Ca (26%). T. gondii contained such granules, as do other eukaryote cells, including yeast (Sall et al 1956), protozoans (Rosenberg 1966;Dvorak et al 1988;Zierold and SchaÈ fer 1988;LeFurgey et al 1990;Schlatterer et al 1994;Scott et al 1997), and many invertebrates (Lowenstam 1972;Howard et al 1981). The diameter of these BGs (150 51 nm) is similar to those in Dictyostelium discoideum (200 nm) and T. cruzi (200 90 nm), and less than those in Tetrahymena pyriformis (200±2000 nm).…”

“…The diameter of these BGs (150 51 nm) is similar to those in Dictyostelium discoideum (200 nm) and T. cruzi (200 90 nm), and less than those in Tetrahymena pyriformis (200±2000 nm). Granules are generally membrane-bounded vesicles associated with the endoplasmic reticulum (ER) or Golgi system (Simkiss 1976; Watabe et al 1976;Schlatterer et al 1994 Brand et al 1965), pyrophosphate in T. pyriformis (Rosenberg 1966) and in Helix aspera (Howard et al 1981)], and the major cation was calcium (most cestodes; Von Brand et al 1965) or iron (Lowenstam 1972). They also contain minor ions, such as Al, B, Ba, Cd, Cr, Na, Pb, Mn, Si, Sn, Zn (Von Brand et al 1965;Silverman et al 1983;Simkiss and Mason 1983).…”