Structural Staining Techniques

Structural Staining TechniquesActivity 29. After the samples were treated with PAS reagent, what part of the cell can be observed? Explain why.

PAS reagentPrinciple: The PAS stain is a histochemical reaction in that the periodic acid oxidizes the carbon to carbon bond forming aldehydes which react to the fuchsin-sulfurous acid which form the magenta color.PAS staining is mainly used for staining structures containing a high proportion ofcarbohydratemacromolecules (glycogen,glycoprotein,proteoglycans), typically found in e.g.connective tissues,mucus, theglycocalyx, andbasal laminae.This techniquehighlights molecules in the cell with high carbohydrate content such as mucins, glycogen, and the basement membrane.1. Differentiate Feulgens reaction from PAS reaction.

TechniqueFeulgens ReactionPAS ReactionStainFast GreenPeriodic Acid (HCl)CounterstainSchiffs ReagentSchiffs ReagentMoleculechromosomal materialorDNAGlycogen, neutral mucosubstances, basement membranes, collagen fibers, glycolipids and phospholipidsCarbon Compounddialdehydesdialdehydes

Resulting ColorMagenta against GreenMagenta against Blue11. Differentiation of blood cells and neuron PAS method.

Neuron cells

Neuron cells

Blood cells