Q.3 Sudan Black is used for staining of
(1) Protein
(2) Lipid
(3) Carbohydrate
(4) Cytoskeleton
Sudan Black is a vital histochemical stain used in microscopy to visualize specific cellular components. Knowing what Sudan Black staining targets helps in cytology, pathology, and exam prep.
Correct Answer: Option (2) Lipid
Sudan Black B, a fat-soluble lysochrome dye, binds to neutral lipids like triglycerides, phospholipids, and lipoproteins, producing blue-black granules. It’s commonly applied on frozen sections or smears to detect fat droplets in tissues or lipid-rich granules in leukocytes (e.g., myeloid cells in AML diagnosis).
Example: In bone marrow smears, it stains azurophilic granules black, distinguishing AML from ALL.
This non-specific affinity for lipids makes it a standard for steatorrhea tests and fat storage diseases.
Why Other Options Are Incorrect
-
Option (1) Protein
Proteins require stains like Coomassie Blue or silver stains; Sudan Black doesn’t bind proteins due to its lipophilic nature. -
Option (3) Carbohydrate
Carbs use PAS (periodic acid-Schiff) or Alcian Blue; Sudan Black ignores polysaccharides like glycogen. -
Option (4) Cytoskeleton
Microtubules/actins need phalloidin or anti-tubulin antibodies; no lipid component in cytoskeleton for Sudan Black binding.
Stain Comparison Table
| Target | Common Stain | Color Produced |
|---|---|---|
| Lipid | Sudan Black B | Blue-black |
| Protein | Coomassie Brilliant | Blue |
| Carbohydrate | PAS | Magenta |
| Cytoskeleton | FITC-Phalloidin | Green fluorescence |
Master Sudan Black staining for accurate lipid identification in research and diagnostics.
