Chapter 10: Microorganisms Flashcards
Acid-fast stains may be negative if the tissue was fixed in:
Carnoy, it will make the tissue non-acid fast.
With the Fite stain, what color does the microorganisms stain?
Red, by Carbol Fucshin.
After Schiff reagent, tissues are rinsed in a sulfite solution in order to:
Remove the excess leucofuchsin.
In the Brown-Hopps modification of the Gram stain for tissues, Gram + organisms appear:
Blue-black.
The property on which the acid-fast stain depends is its:
Ability to resist decolorization with dilute acids.
What is a good stain for demonstrating fungii?
The PAS method.
What is the best stain for the demonstration of Mycobacterium leprae?
The Fite method.
How does the PAS differ from the Gridley technique?
The type of oxidizer used. The PAS uses periodic acid and the Gridley method uses chromic acid.
Artifactual precipitate seen in the Grocott (GMS) stain may be the result of using:
Unclean (non-chemically cleaned) glassware.
Sperical or ovoid bacteria are classified as:
Cocci.
A medically important protozoan is:
Giardia lambia.
The basic structure of filamentous fungi is the:
Hypha.
What are carbol-fuchsin methods specific for?
Mycobacteria.
The auramine-rhodamine technique will demonstrate:
Mycobacterium tuberculosis.
What does carbol-fuchsin contain?
Basic fuchsin and phenol (carbolic acid).
The term “mycosis” is used to describe a disease caused by:
Fungi.
Stains for the demonstration of spirochetes are based on their property of:
Argyophilia, they bind to silver and don’t reduce it.
The differential staining achieved with the Gram stain is due to what?
Differences in the bacterial cell walls.
What is a common fluorescence technique?
The auramine-rhodamine.
The PAS reaction will demonstrate fungi, because the cell wall contains:
Carbohydrates.
What does the Gridley stain use?
Chromic acid and schiff reagent.
In the Hotchkiss-McManus modification of the PAS technique, how are aldehydes formed?
The periodic acid.
What is the preferred fixative for the Warthin-Starry technique?
10% NBF.
What is the “developer” in the Warthin-Starry stain?
Hydroquinone.