Bindungsort und Bindungsmodus von Aldehydfuchsin in den B-Zellen des Inselapparates

A histochemical investigation of the mechanism of Aldehyde Fuchsin staining of pancreatic B-cell granules

“…For example, if enol groups of the granule membrane were responsible for binding Aldehyde Fuchsin, as suggested by von Denffer (1973), these groups also could account for results observed here. Methylation of tissue enols should form methyl ethers which would be resistant to saponification by potassium hydroxide (Morrison & Boyd, 1966 The slight affinity of colloidal iron for B-cell granules could indicate the presence of some acidic mucosubstance, but the faintness of the staining suggests that anions present must be weak and/or few in number.…”

“…Von Denffer & Mertz (1972) observed that B-cell granules of mouse pancreas were not stained by Alcian Blue and attributed this to the absence of sulphur acids associated with granules. Von Denffer (1973) investigated the"effects of pretreating pancreatic B-cell granules with histochemical blocking agents prior to staining with Aldehyde Fuchsin and concluded that the following moieties were not responsible for binding Aldehyde Fuchsin: thiols, disulphides, tyrosyl-hydroxyls, phospholipids and amino groups. He proposed that staining of the B-cell granules could result from covalent binding of tissue enol groups of the granule membrane with the azomethine moiety of Aldehyde Fuchsin to form stable enol ethers.…”

“…Von Denffer (1973) attempted to locate by electron microscopy the site of Aldehyde Fuchsin binding with pancreatic B-cell granules. He combined a ferricferricyanide reagent with Aldehyde Fuchsin and after staining pancreas with this combined stain, reported an accumulation of electron-dense material on the outside of the B-cell granule membrane.…”