What is feulgen stain used for?

The Feulgen technique selectively stains DNA, and under controlled conditions, can be used for the photometric determination of DNA content. The reaction consits of two steps. Fixed material is treated for 8-10 min with 1N HCl in a water bath or oven at 60°C.

What is the reaction to feulgen stain?

The Feulgen reaction is based on Schiff’s reaction for aldehydes whereby, by acid hydrolysis, the liberated aldehydes of the deoxy sugar are allowed to react with fuchsin–sulphurous acid to yield a typical magenta colour reaction.

What type of stain is feulgen stain?

Feulgen stain is a staining technique discovered by Robert Feulgen and used in histology to identify chromosomal material or DNA in cell specimens. It is darkly stained. It depends on acid hydrolysis of DNA, therefore fixating agents using strong acids should be avoided.

How feulgen stain is prepared?

In a routine Feulgen staining technique, slides are immersed in 5 mol/L HCl for 15 minutes, rinsed with distilled water for 3 minutes, stained with Schiff’s reagent for 90 minutes, washed for 10 minutes and finally stained with 1% light green for 15 minutes (7-8).

What is Feulgen-positive and negative?

SUMMARY. The nuclei of the male and female gametocytes of the malarial parasites {Plasmo- dium and Hepatocystis) are Feulgen-negative, while the nuclei of the gametocytes of Hepatozoon, which are not sexually differentiated, are Feulgen-positive.

Who have developed Feulgen technique?

Abstract. The Feulgen reaction proposed by Feulgen and Rossenbeck 75 years ago is one of the cytohistochemical reactions most widely used in biology and medicine.

Which bond is cleaved by acid hydrolysis during Feulgen staining of DNA?

The Feulgen reaction consists of two steps. Initially, acid hydrolysis is performed, usually for 812 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.

Which of the following is the best stain for electron microscopy?

The most widely used stains in electron microscopy are the heavy metals, uranium and lead. The double contrast method of ultrathin sections with uranyl acetate (UA) and lead citrate is the standard contrasting technique for electron microscopy (Figure 1 and 2).

Which staining method acid hydrolysis is done to bring cleavage of nitrogen base from DNA?

Schiff’s reagent is the stain used in this technique. It specifically stains the DNA due to reaction of Schiff’s (or Schiff’s-like) reagent with aldehyde groups exposed at C1 as the result of the nitrogen bases cleavage from deoxyribose by 1N HCl hydrolysis at 60°C within about 10 minutes.

Which is the stain commonly used in electron microscopy Mcq?

Explanation: In negative-staining the electron opacity of the surrounding field is increased by using an electron-dense material such as phosphotungstic acid as a stain.

Which stain is used during transmission electron microscopy?

Osmium tetraoxide OsO4 is a widely used staining agent used in transmission electron microscopy (TEM) to provide contrast to the image.

Does feulgen stain RNA?

RNA, where the purine linkage is acid-stable, did not react. Feulgen staining enabled nuclei to be clearly identified in animal and plant cells. The next step was to find a quantitative method for the estimation of the DNA in the nucleus. A suitable method for this was introduced by Caspersson (mid-1920s–ca.