Differential Staining of Nucleic Acids?

Abstract

IT is true that in the cell nucleus one finds substances in addition to DNA, and that these may play an important part in certain staining procedures. If, however, a dye known to be basic stains a structure known to contain DNA and known not to contain significant quantities of other acid (basophilic) substances, it is reasonable to regard DNA as the substrate primarily responsible for such staining. The same argument applies to nucleoli and pancreatic cytoplasmic chromidial substance, the basophilia of which is known to be due to RNA. This is very far from claiming chemical specificity for staining by a single basic dye or by a binary mixture; and, contrary to the impression apparently gained by Dr. van Duijn, no such claim was made. All these methods, including methyl green/pyronin, stain mast cell granules, cartilage matrix, mucin and other acidic substances in addition to nucleic acids, and one therefore cannot claim that an unknown substrate stained by any of these methods is nucleic acid (either DNA or RNA) unless one uses such additional procedures as the enzymatic digestions mentioned by Dr. Van Duijn.