Lab I Exam: Mycology

Question 1

tinea barbae

Answer 1

beard

Question 2

tinea captitis

Answer 2

scalp

Question 3

tinea corporis

Answer 3

body

Question 4

tinea cruris

Answer 4

groin (jock itch)

Question 5

tinea faicei

Answer 5

face

Question 6

tinea manum

Answer 6

hand

Question 7

tinea pedis

Answer 7

foot (athlete’s foot)

Question 8

tinea unguium

Answer 8

nail

Question 9

What does the word “tinea” mean?

Answer 9

latin word for ringworm

Question 10

Name the short lateral structure that will develop when certain yeast are incubated at 37 degrees Celsius in rich medium.

Answer 10

germ tubes

Question 11

Name on yeast that is germ tube positive.

Answer 11

Candida albicans

Question 12

At what temperature should chlamydospore agar be incubated?

Answer 12

room temperature - 25 C

Question 13

Where should technologist look for spores on a chlamydospore agar plate?
What color and shape are they?

Answer 13

near the edge of the cover slip

blue and round

Question 14

What is the principle of the India ink preparation?

Answer 14

take a drop of india ink with a drop of organism and view under high power; india ink particles will bounce off capsule and will see clear halo

Question 15

What organism is India ink prep especially used for?

Answer 15

Cryptococcous neoformans

Question 16

What type of specimen is most commonly used for India ink preps?

Answer 16

Spinal fluid

Question 17

What reagent should be used for the examination of the reproductive structures of molds that are already growing in a culture?

Answer 17

LPCB- lactophenol cotton blue

Question 18

What technique can be used to “save” wet preps for future use?

Answer 18

Wipe off excess LPCB from edges of coverslip, then seal with colorless fingernail polish; keeps in moisture

Question 19

Name several media used for primary isolation of fungi.

Answer 19

Sab- Sabouraud's 
SDA - Sabouraud's dextrose agar
Mycosel/Mycobiotic
SabsC 
BHI- brain heart infusion for systemic fungus

Question 20

Why would you incubate a culture for fungi at 25 degrees C and 37 degrees C?

Answer 20

Fungus may be dimorphic/diphasic; at 25 degrees it will grow in mold phase, at 37 degrees it will grow in yeast phase.

Question 21

What term is used for fungi that grow differently at 25 and 37 degrees?

Answer 21

Dimorphic/diphasic

Question 22

Why do mycologist use KOH? What specific protein does the reagent affect?

Answer 22

to clear, or dissolve, the keratious material from the body so fungal elements stand out; keratin

Question 23

Name at least two fungal elements that could be seen in a KOH prep.

Answer 23

budding yeast
pseudohyphae
arthrospores
blastospores
septate hyphae
aseptate hyphae

Question 24

What is the difference between ectothrix and endothrix hair invasion?

Answer 24

ectothrix-invade outside/surface of hair shaft

endtothrix-invade hair shaft;dermatophyte

Question 25

What genus of fungus causes ringworm?

Answer 25

Microsporum
Trichophyton
Epidermophyton

Question 26

What genus of fungus exhibits dimorphism?

Answer 26

Blastomyces
Coccidiodies
Paracoccidiodies
Histoplasma
(genera are subcutaneous-sporothrix)

Question 27

What genus of fungus is a frequent contaminant?

Answer 27

Aspergillis

Penicillium

Question 28

What is a slide culture?

Answer 28

best way to observe fungi in the natural state

inoculate agar and place coverslip on it. fungi grows under coverslip, showing perfect morphology