A silver impregnation method for labeling both Alzheimer paired helical filaments and their polypeptides separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis

Abstract

The Gallyas silver impregnation which is specific to neurofibrillary changes of paired helical filaments (PHF) and 15 nm straight filaments, was adapted to stain polypeptides separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Both PHF and tau polypeptides were readily and consistently stained by the Gallyas stain. This technique stained PHF greater than tau greater than high-molecular-weight microtubule-associated polypeptides (MAPS). Tubulin was stained only weakly. Neurofilament triplet, ubiquitin, bovine serum albumin and histones were unstained. The staining of PHF and tau polypeptides by Gallyas silver stain is consistent with the presence of tau in PHF.