Exam 1 - Mycology Diagnostic Tests

Question 1

Potassium hydroxide (KOH)

Answer 1

• quick and inexpensive
• causes most human tissue elements to become dissolved leaving fungal elements such as conidia or hyphae that retain their shape and color and can be seen with light microscop

Question 2

Periodic Acid-Schiff (PAS) reaction

Answer 2

• is used to stain polysaccharides found in the cell walls of molds and yeasts.
• has aldehyde groups that bind to basic fuchsin and stain the fungal elements red.

Question 3

Giemsa stain

Answer 3

• is used when intracellular structures are to be examined.

- stains tissue and blood cells showing blue-colored intracellular yeasts, sometimes with a halo around them.

Question 4

nigrosin stain

Answer 4

is used to demonstrate capsules around cells