What is the Difference Between Endospore Staining and Flagella Staining

The key difference between endospore staining and flagella staining is that endospore staining is a differential staining procedure used to visualize endospores produced by a few bacterial genera, while flagella staining is a staining procedure that visualizes flagellum/flagella in motile bacteria.

Staining is a technique that is commonly used to characterize bacteria. These staining techniques differentiate bacteria based on physical and chemical differences. Certain staining techniques visualize cellular constituents such as flagella, endospores, etc. Endospores are tough, dormant, non-reproductive structures formed by bacteria as a response to unfavorable growth conditions. Flagella are microscopic hair-like structures that help bacteria to move. Certain genera produce endospores, while certain genera have flagella. Therefore, the staining of flagella and endospores can be used to differentiate and characterize bacteria.

CONTENTS

1. Overview and Key Difference
2. What is Endospore Staining
3. What is Flagella Staining
4. Similarities – Endospore Staining and Flagella Staining
5. Endospore Staining vs. Flagella Staining in Tabular Form
6. FAQ – Endospore Staining and Flagella Staining
7. Summary – Endospore Staining vs. Flagella Staining

What is Endospore Staining?

Endospores are dormant, non-reproductive structures produced by certain bacteria within their vegetative cells. Some bacteria produce endospores in response to unfavourable growth conditions, especially the lack of nutrients. Bacteria can lie dormant due to endospores. They are protective structures for survival. However, endospores do not have a role in reproduction. Bacteria in the firmicute phylum mainly produce endospores. Two genera that are known to form endospores are Bacillus and Clostridium.

Endospore staining is a differential staining technique used to visualize endospores in order to differentiate bacteria that produce endospores. This procedure selectively stains bacterial endospores in green colour while staining vegetative cells in brownish red to pink. One of the procedures for endospore staining, named Schaeffer-Fulton’s method, is described below.

Steps of Endospore Staining Method

1. Make a bacterial smear on a clean glass slide using sterile techniques and air dry.
2. Then heat fix the smear covering with a blotting paper.
3. Saturate the blotting paper with the stain named Malachite green and steam for 5 minutes using a boiling water bath (make sure the paper is moist by adding more dye whenever required).
4. Wash the slide in tap water.
5. Stain the slide with 0.5% safranin for 30 seconds.
6. Wash with tap water and blot dry.
7. Observe under the microscope.

What is Flagella Staining?

Flagella are thin structures that help bacteria to move. Only motile bacteria have flagella. Flagella staining is a technique that visualizes the presence and arrangement of flagella. It is done for the identification of motile bacterial species. Unstained flagella cannot be seen under a light microscope. When stained, chemicals make a thickened coat around the flagella, enabling them to be seen with a light microscope.

Steps of Flagella Staining

1. Place a drop of water on a clean glass slide.
2. Using a sterile inoculating loop, gently touch the bacterial colony and then drop the water without touching the slide. Do not mix.
3. Make a smear by tilting the slide to flow the drop to the opposite end of the slide.
4. Air dry the slide at room temperature. Do not heat fix.
5. Flood the slide with Leifson Flagella Stain for approximately four minutes.
6. Rinse the stain carefully.
7. Tilt the slide to allow excess water to run off.
8. Air dry slide at room temperature.
9. Examine the slide under the light microscope using the oil immersion objective.
10. If flagella are present, they will appear in purple color.

What are the Similarities Between Endospore Staining and Flagella Staining?

• Endospore and flagella staining are two techniques that visualize two different structures of bacteria for the purpose of identification.
• In fact, these techniques allow the differentiation of specific bacterial structures.
• Both techniques need different stains.
• Both techniques require the preparation of bacterial smears.
• The final step of both techniques is the observation under the microscope.

What is the Difference Between Endospore Staining and Flagella Staining?

Endospore staining visualizes bacterial endospores, while flagella staining visualizes flagella and their arrangement in motile bacterial cells. Thus, this is the key difference between endospore and flagella staining. Furthermore, endospores stain in green color at the end while flagella stain in purple color at the end of the procedure. Malachite green and safranin are used in endospore staining, while Liefson stain is used in flagella staining.

The infographic below presents the differences between endospore and flagella staining in tabular form for side-by-side comparison.

FAQ: Endospore Staining and Flagella Staining

Why are endospores and flagella difficult to stain?

Endopores and flagella are two structures that are highly resistant to normal stains since both have tough protein coats around them.

What dye is used in flagella staining?

Liefson stain is used in flagella staining.

What is the principle of Endospore staining?

In endospore staining, endospores are stained in a manner so that they can be distinguished from the vegetative part of the cell.

Summary – Endospore Staining vs. Flagella Staining

Endospore and flagella staining are two structural staining techniques for bacteria differentiation. Endospore staining aids the visualization of bacterial endospores within the vegetative cells. Flagella staining aids the visualization of flagella and their arrangements in motile bacteria. Both procedures are important in bacterial characterization. So, this summarizes the difference between endospore and flagella staining.

Reference:

1. “Bacterial Flagella Stain Protocol.” – American Society for Microbiology.
2. “Endospore Stain Protocol.” – American Society for Microbiology.

Image Courtesy:

1. “OSC Microbio 02 04 Endospores” By CNX OpenStax – (CC BY 4.0) via Commons Wikimedia
2. “Bacteria” By Carolina Biological Supply (CC BY-NC-ND 2.0 DEED) via Flickr