Investigations of dye binding in the sequential staining of mucosaccharides by Alcian Yellow-Alcian Blue. II. Spot tests and experiments on dye-mucopolysaccharide (glycosaminoglycan) precipitates

Synopsis

The amounts of dye bound to mucopolysaccharide in the histochemical sequential staining Alcian Yellow-Alcian Blue method were determined by studying dye-mucopolysaccharide (glycosaminoglycan) precipitates in test-tube and spot test experiments. In the second step (Alcian Blue) of the method, previously bound Alcian Yellow was released into the staining solution and simultaneously the precipitate took up Alcian Blue. The amounts of Alcian Yellow released and Alcian Blue taken up varied for different mucosaccharides, and depended on the staining time of the second step (Alcian Blue) of the sequence, as well as on the concentration of dye and salt in the Alcian Blue solution. It is thought that, among other things, the Alcian Blue in solution displaces some of the bound Alcian Yellow. Some observations could be explained by the aggregation of dye molecules. The results were in agreement with previous histochemical observations.