Example of nuclear stain is:-

Key Points

• Cells and cellular structures are generally colourless and transparent.
• Thus staining them gives better visibility under microscopes.
• Different types of stains are used for staining different cells and tissues of an organism.
• Nuclear stains are used to stain the cell nucleus specifically.
• The bulk content of the nucleus is nucleic acid and so, nucleic acid stains are used as nuclear stain.

Important Points

• Haematoxylin is a commonly used nuclear stain.
• Origin - Heartwood of Haematoxylum campechianum.
• Staining Mechanism - It produces a blue dye called Hematin by oxidation reaction with nuclear histone proteins, causing the nucleus to appear purple-blue.

Additional Information

• Eosin:
  • It is a class of pinkish-red fluorescent dye.
  • It is used to stain cytoplasm, RBCs, collagen and muscle fibres.
  • It is used as a counterstain to Haematoxylin.
  • Haematoxylin and eosin (H&E) is often used together for screening cell structure and shape in a tissue sample, helping in diagnosis of diseases like cancer.
• Safranin:
  • It is a red stain that is widely used as a counterstain in Gram staining and endospore staining methods.
  • It is also used for preparing temporary mounts as it is easily taken up by plant materials like lignin and highlights the cells and tissues under a microscope.
• Borax-carmine:
  • It is a red dye that is used for staining cytoplasmic organelles.
  • It is used for observing large animal tissues under optical microscopy.