Feulgen Reaction

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Feulgen reaction

[′fȯil·gən rē‚ak·shən]
(analytical chemistry)
An aldehyde specific reaction based on the formation of a purple-colored compound when aldehydes react with fuchsin-sulfuric acid; deoxyribonucleic acid gives this reaction after removal of its purine bases by acid hydrolysis; used as a nuclear stain.

Feulgen Reaction


a means for the histochemical detection of deoxyribonucleic acid (DNA) in animal and plant cells, as well as in bacteria. It was proposed in 1924 by the German chemist R. Feulgen.

The Feulgen reaction consists of two steps. Initially, acid hydrolysis is performed, usually for 8–12 min, resulting in the cleavage of the nitrogen bases and formation of aldehyde groups. The preparations are then placed in light yellow Schiff reagent (fuchsine-sulfurous acid), which forms bonds with these groups. The red-violet product formed in this step is evidence of the presence of DNA. The Feulgen reaction can be carried out after the use of any fixative (with the exception of Bouin’s fluid, which contains picric acid). The Feulgen reaction is used for the quantitative determination of DNA. Various modifications of the reaction exist for determining the location and structure of DNA with the aid of electron microscopes.

References in periodicals archive ?
The epithelial cells were dispersed on slides, air-dried, fixed in methano-glacial acetic acid (3:1, v/v) at 4[degrees]C for 24 h and stained with the Feulgen reaction (hydrolysis with 5N HCl for 60 min at room temperature, staining with Schiff's reagent for 60 min, followed by 3 washes of 5 min each in sulfurous water).
Replicate slides with or without the 5% hot TCA extraction were stained to confirm DNA extraction, using the Feulgen reaction for DNA as described elsewhere (Rasch 2003).
13 were stained with the Feulgen reaction for DNA to illustrate aspects of the flattened coil vs.
Salivary glands were isolated, and one gland from each tick was stained by the Feulgen reaction for microscopic examination for inclusions (7); the other gland was prepared for DNA extraction.
According to Greilhuber (1998) suboptimal performance of the Feulgen reaction is one of the most common sources of reported intraspecific DNA variation.
1986) on very compact erythrocyte nuclei would be compromised, had the authors not used a fluorescence version of Feulgen reaction in which a high density of staining does not matter to the extent that it does in absorption cytometry.