Flagella stain – Principle, Procedure, and Result:

Flagella stain principle

         Flagella are intricate filamentous cytoplasmic structures that protrude through the cell wall. The flagellin protein, which makes up the majority of these unbranched, lengthy, thread-like filaments, is delicately woven into the cell membrane. They are roughly 5–16 m long and 12–30 nm in diameter. They are in charge of bacterial motility. The capacity of some bacteria to cause disease and to survive depends heavily on their motility.

Read it for further details on flagella and its mechanism of movement

Functions of Flagella

  • Movements
  • Sensation
  • signal processing
  • Adhesion
  • This causes fluids to flow over the surface of cells anchored in a tissue, such as the epithelial cells lining our air passageways (e.g causing mucus with particles to go toward the throat). Most people agree that flagella are significant virulence agents

            Using a bright field microscope and common stains, like the Gram stain or a basic stain, it is impossible to see flagella because they are too thin. When the quantity and arrangement of flagella are crucial to the identification of species of motile bacteria, a wet mount approach is employed to stain the bacteria. This method is straightforward and helpful. For the stain to bind to the flagella in layers and be visible throughout the staining operations, a mordant is used.

Flagella stain reagents

       To keep the bacterial flagellum within the range of size visible by light microscopy, all flagella stains employ mordants like tannic acid and potassium alum to coat and thereby thicken the flagellum. Tannic acid is a component of the Presque Isle method while tannic acid is a component of the Leifson flagella stain method.

Materials required

Manufactured flagella stains (there are different types of flagellation in the slide boxes).

Flagella stain procedure

  • On blood agar, cultivate the organisms to be dyed for 16 to 24 hours at room temperature.
  • A microscope slide should have a tiny drop of water added.
  • submerge a sterile inoculating loop into sterile water,
  • Briefly apply the water loop to the colony’s edge (this allows motile cells to swim into the droplet of water).
  • The water drop on the slide should be touched by the loop of motile cells.
  • Put a cover slip over the water drop on the slide that is just a little murky. Just about enough liquid is present in a suitable wet mount to cover the area beneath a cover slip. It is best to have a small amount of air around the edge.
  • Look for motile cells on the slide under 40x magnification.
  • Leave the slide at room temperature for 5 to 10 minutes if you can see any moving cells.
  • On the edge of the coverslip, lightly dab 2 drops of RYU flagella stain. Using capillary action, the stain will spread and combine with the cell solution.
  • If the cells have been at room temperature for 5 to 10 minutes, look for flagella.
  • At 100x, flagella-containing cells can be seen.


  • flagella present or absent
  • Flagella per cell count
  • Flagella’s position within each cell
  • Peritrichous
  • Lophotrichous
  • Polar
  • The length of the wavelength and whether it is “tufted”





Rimsha Bashir
Rimsha Bashir

Rimsha Saith is a highly knowledgeable microbiologist with a keen interest in the field. Her expertise and passion are in her writing for Microbiology. As a writer, Rimsha has authored numerous articles that have been well-received by both health and medical students and industries.

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