Exercise 4 studyguide

Difference between differential and structural stain?

Differential differentiates organisms that are a part of the cell, while structural stain identifies structures separate from cell.

Example of differential stain besides gram stain?

Acid-fast stain

Example of structural stain?

Endospore stain

What method do we use for Acid-Fast staining?

ziehl-neelsen method

Acid-fast microorganisms have ____ in their cell walls, which makes their cell walls ____?

They have high mycolic acid content in their cells walls, which makes them waxy and resist staining

What do you have to do to force the primary dye to penetrate the waxy cell wall?

use steam!

Fastness means to:

retain the dye when challenged by a decolorizer

Reagents for acid fast:

Primary Dye: Carbol fuchsin (with steam)

Decolorizer- Acid Alcohol

Secondary dye/counterstain: methylene blue 

Procedure of acid fast:

-steam with carbol fuchsin for 3 minutes

-rinse with water

-decolorize with acid alcohol for 12 seconds

-counterstain with methylene blue for 1 minute

Acid-fast cells retain the dye after decolorization because of:

of the high wax content

What color is a positive result for acid-fast?

Cerise

(pink/violet)

What color is a negative result for acid-fast?

Blue

Non-acid fast cells will readily ____ and then we counterstained with methylene blue

decolorize

Example of a acid fast genera:

Mycobacterium’s, high mycolic acid

SPORE STAINING:

what method do we use for spore staining?

Schaeffer-Fulton Method

Spore staining is a structural stain to detect _______

dormant forms of bacteria 

-that keep DNA safe in endospores

What is it called when the endispore is realeased?

Free spores

How do we force primary dye into resistant endospores?

Steaming

Are stained spores resistant to decolorization?

Yes

Spore staining reagants:

Primary Dye: malachite green(with steam)

Decolorizer: water

Secondary dye/counterstain: Safranin

Do spores reproduce?

NO, spores don’t reproduce

What color are spores?

Green

What color will the rest of the bacteria be?

Pink

Spore staining procedure:

1. steam with malachite green for 3 minutes

2. Decolorize with water very well.

3. counterstain with safranin

Endospores look like what in spore staining:

Spores are green inside pink bacterial cell

Free spores look like what in spore staining?

small green oval bodies

What does this stain look like if no spores are present?

only pink cells will be observed

3 main types of spore forming bacteria?

1. Bacillus (Gram-Pos rod)

2. Clostridium (Gram pos rod)

3. Sporosarcina

Bacillus Anthracis importance with spores:

anthrax spores were mailed out.