Polysaccharides

Although the term carbohydrate is a general concept and applies to all the sugars and their derivatives, the name polysaccharides will be preferred as they are the common macromolecular substrates to be recognized in microscopy. Carbohydrates may be classified on account of their chemistry, histochemical responses in diagnostic pathology, or distribution and function in nature [1]. Some issues are central to this chapter: the use of bisazo dyes and fluorescent brighteners, chlorotriazines and PAS reaction, ionic binding and metachromatic reactions. Staining and fluorescence methods applied for histochemistry of polysaccharides have been reviewed [1-4], and some of them, in special glycoproteins (i.e. Congo red for amyloid), will be described in Chapter 13.11.3. More specific procedures involving the use of lectins can be found in Chapter 4.5.2.

Keywords: Acid glycosaminoglycans, Acridines, Aryl-oxazoles, Boronic acids, Brightening agents, Carbocyanines, Cell walls, Chloro-triazines, Congo red, Curcumin, Lignin, PAS reaction, Ru(II)-bipyridine, Sirofluor, Trypan blue.