Do stains adhere to capsules?

Do stains adhere to capsules?

Bacterial capsules are non-ionic, so neither acidic nor basic stains will adhere to their surfaces. Therefore, the best way to visualize them is to stain the background using an acidic stain and to stain the cell itself using a basic stain. We use India ink and Gram crystal violet.

Which stain is used in capsule staining?

In this type of capsule staining procedure, the primary stain is crystal violet, and all parts of the cell take up the purple crystal violet stain. There is no mordant in the capsule staining procedure. A 20% copper sulfate solution serves a dual role as both the decolorizing agent and counterstain.

What would a capsule look like in a Gram stain?

In the Gram staining protocol, two different colored stains can result. Dark purple staining indicates that the bacteria are Gram-positive and that they have retained the crystal violet stain. Against this dark background, the capsules of the bacteria, if present, will appear as a clear halo around the cells.

Why is the presence of a capsule clinically significant?

Lab 10 (Q3): Why is the presence of a capsule clinically significant? Capsules enhance a bacterium’s ability to evade phagocytosis, and the body’s immune system. Ability to “hide” from the immune system.

Why is the capsule stain not heat fixed?

Most bacteria have some kind of CAPSULE. Capsular material is very moist (slimy) and any heating will cause it to shrink – it is for this reason that we will not heat fix the slide before staining.

How do I make a capsule stain?

Procedure of Capsule Stain

1. Prepare thin smears of bacterial culture on a microscope slide.
2. Allow the smear to only air-dry.
3. Apply 1% crystal violet and allow it to remain on the slide for 2 minutes.
4. With the slide over the proper waste container provided, gently wash off the crystal violet with 20% copper sulfate.

Why is endospore stain used?

The endospore stain is a differential stain used to visualize bacterial endospores. Endospores are formed by a few genera of bacteria, such as Bacillus . By forming spores, bacteria can survive in hostile conditions. Spores are resistant to heat, dessication, chemicals, and radiation.

How can you tell if the bacteria are making endospores under Gram stain?

The Gram Stain actually stains only the living portion of vegetative bacteria, but the ‘hole’ or clear space inside the purple bacteria indicates that their might be spores present (this is critical if you do not know your bacteria as some have other structures which do not stain), and the gram stain is useless to …

What happens if you forget to Decolorize a Gram stain?

During the decolorization step, the gram positive bacteria become dehydrated, trapping the crystal violet-iodine complexes within the multi-layered peptoglycan wall. If you skip this step, gram negative bacteria retain the purple dye. If you decolorize properly, the saffrin dye will dye the gram negative bacteria pink.

What kind of stain do you use for capsule stain?

B. Anthony’s stain method. In this type of capsule staining procedure, the primary stain is crystal violet, and all parts of the cell take up the purple crystal violet stain. There is no mordant in the capsule staining procedure.

What is the principle of negative capsule staining?

Principle of Capsule Staining. Capsules stain very poorly with reagents used in simple staining and a capsule stain can be, depending on the method, a misnomer because the capsule may or may not be stained. Negative staining methods contrast a translucent, darker colored, background with stained cells but an unstained capsule.

How is copper sulfate used in capsule staining?

There is no mordant in the capsule staining procedure. A 20% copper sulfate solution serves a dual role as both the decolorizing agent and counter stain. It decolorizes the capsule by washing out the crystal violet, but will not decolorize the cell. As the copper sulfate decolorizes the capsule,…

Is there mordant in the capsule staining procedure?

There is no mordant in the capsule staining procedure. A 20% copper sulfate solution serves a dual role as both the decolorizing agent and counterstain. It decolorizes the capsule by washing out the crystal violet, but will not decolorize the cell. As the copper sulfate decolorizes the capsule, it also counterstains the capsule.