Mycology

Question 1

What are saprophytes?

Answer 1

Eating dead matter

Question 2

What are the three ways in which fungi can adversely affect us?

Answer 2

1. allergens
2. Toxin producers
3. infectious agents

Question 3

Does the development of fungal allergies require colonization?

Answer 3

no

Question 4

What are mycotoxins?

Answer 4

Toxins produced by fungi

Question 5

What are ergot alkaloids?

Answer 5

Fugal mycotoxin that produces hallucinations

Question 6

What are alfaltoxins?

Answer 6

Hepatotoxins from fungus that grows on peanuts

Question 7

What is stachybotrys?

Answer 7

A mycotoxin produced by household mold. Brain effects

Question 8

What are the two typical targets of antifungal therapies?

Answer 8

Fungal cell wall

Membrane sterol composition (ergosterol)

Question 9

What is the lipid component of fungal membranes that is analgous to cholesterol, and serves as a target for antifungal therapy?

Answer 9

Ergosterol

Question 10

Will abx that affect bacterial cell walls have any effects on fungal cell walls?

Answer 10

No

Question 11

What are the three major components of the fungal cell wall?

Answer 11

Mannan
Glucan
Chitin

Question 12

Are fungal cells wall very or poorly immunogenic?

Answer 12

Very

Question 13

Is the capsule that some fungi produce immunogenic?

Answer 13

Yes

Question 14

What are the two categories of fungi?

Answer 14

Yeast

Molds

Question 15

What is the term that describes fungi that can transition from a yeast form to a mold form?

Answer 15

Dimorphic

Question 16

How many cells do yeast have? What shape are they?

Answer 16

Unicellular spheres or ellipsoids

Question 17

How do yeasts reproduce?

Answer 17

Budding

Question 18

A germ tube is diagnostic for what fungi?

Answer 18

Candida albicans

Question 19

What are the small buds that are produced from the process of budding?

Answer 19

Blastoconidia

Question 20

What are pseudohyphae?

Answer 20

Long extensions of fungi “chains of buds that never broke off”

Question 21

What are hyphae?

Answer 21

a long, branching filamentous structure of a fungus. In most fungi, hyphae are the main mode of vegetative growth.

Question 22

What is a mass of hyphae?

Answer 22

Mycelium

Question 23

Molds that are infectious (and dimorphic) grow in what form: yeast or mold?

Answer 23

Yeast

Question 24

Reproductive fungi units produced Asexually are known as what?

Answer 24

Conida

Question 25

Reproductive fungi units produced *sexually* are known as what?

Answer 25

Spores

Question 26

Where on existing molds do conidia form?

Answer 26

along hyphae or on stalk like structures known as conidiophores.

Question 27

What are the two forms of hyphae, that are distinguished by the presence/absence of cell walls?

Answer 27

Spetate/aseptate hyphae

Question 28

What are the three different forms of conidia?

Answer 28

Macro Micro Arthro

Question 29

What are arthrocanidia?

Answer 29

Spores that form in the center of a hyphae

Question 30

What is the main diagnostic procedure for identifying fungi?

Answer 30

Visually

Question 31

Conidia which form within a hyphal element are known as what?

Answer 31

chlamydoconidia or arthroconidia.

Question 32

What are superficial mycoses?

Answer 32

Infections of the outermost layer of the skin/hair

Question 33

What are cutaneous mycoses?

Answer 33

infection which extends deep into the epidermis as well as invasive hair and nail infections.

Question 34

What are subcutaneous mycosis?

Answer 34

infections involving the dermis, subcutaneous tissues, muscle, and fascia.

Question 35

What are systemic mycoses?

Answer 35

infections that originate primarily in the lung but may spread to any organ in the body.

Question 36

What are opportunistic mycoses?

Answer 36

infection associated primarily with immunosuppressed individuals.

Question 37

What is characteristic of fungi that can cause systemic mycoses?

Answer 37

Are dimorphic

Question 38

Intact skin, pH, competition with normal bacterial flora, epithelial turnover rate, desiccated nature of the stratum corenum, and mucous membranes are all examples of what type of immunity?

Answer 38

Innate

Question 39

What role do antibodies play in our immune response to fungi?

Answer 39

Antibodies are sometimes produced, but there is little evidence for a role of humoral immunity in resistance or resolution of infection.

Question 40

What is the main immune defense against fungi?

Answer 40

Neutrophils

Question 41

The severity of a disease caused by fungi is dependent on what factors? (4)

Answer 41

Size of innoculation magnitude of tissue destruction ability of fungi to multiply in tissue Immuologic status of host

Question 42

What do macrophages have to do in order to get rid of persistent fungi?

Answer 42

Become activated by IFN-gamma

Question 43

When is topical therapy indicated for a fungal infection?

Answer 43

When the infection is superficial or cutaneous

Question 44

When is systemic therapy of antifungals indicated?

Answer 44

When the fungi are at the subcutaneous level or beyond

Question 45

What is the origin of systemic fungal infections?

Answer 45

Inhalation

Question 46

What are the four examples of systemic mycoses given in class?

Answer 46

``` Histoplasmosis Blastomycosis Paracoccidiodomycosis Coccidioidmycosis Cryptococcosis ```

Question 47

What are the major targets of antifungal drugs? (5)

Answer 47

``` Cell wall synthesis Cell membrane Inhibit protein syn Inhibit nucleic acid syn Disrupt microtubules ```

Question 48

What are the antifungal targets in the cell wall of a fungus?

Answer 48

Glucan/chitin synthesis

Question 49

What is the class of drugs that directly target the cell membrane of a fungus? How do these work?

Answer 49

Polyenes--binding to fungal-specific membrane sterols (ergosterol)

Question 50

What are the classes of drugs that inhibits ergosterol synthesis?

Answer 50

Azoles allylamines thiocarbamates Morpholines

Question 51

What is the class of antifungals that inhibit both RNA and DNA synthesis? What is the scope of fungi that these drugs target?

Answer 51

Nucleoside analogs (like 5-fluorocytosine!) Target yeasts (little effect on dimorphic fungi)

Question 52

What are allyalmines effective in killing? Ineffective?

Answer 52

Effective against dermatophytes Ineffective against yeast

Question 53

What is the MOA of echinocandins?

Answer 53

Inhibit the synthesis of beta-glucans, an important component of the fungal cell wall.

Question 54

What is KI used to treat? How does it work?

Answer 54

Subcutaneous infections caused by sporothrix schencki

Question 55

What is the class of drugs that inhibits cell wall synthesis?

Answer 55

Echinocandins

Question 56

What is the MOA of grisans?

Answer 56

Inhibits microtubule assembly

Question 57

What type of drug is amphotericin B? What is the MOA?

Answer 57

Polyene, binds to ergosterol and causes pore fomation

Question 58

What is the KOH prep used in the lab to identify fungal infections?

Answer 58

Add KOH to tissue scrapings--will dissolve skin tissue at a faster rate than the fungus, and thus allows for visual identification

Question 59

All fungi are gram (positive or negative)?

Answer 59

Positive

Question 60

What is the black stain used in the lab that specifically stains chitin?

Answer 60

Chlorazol black

Question 61

What is the whtie stain used in the lab that specifically fungal cell walls?

Answer 61

Calcofluor white

Question 62

The india ink stain is used to identify what fungus? What is the target here?

Answer 62

Cryptococcus neoformans--stain targets the capsule

Question 63

What is the germ tube test diagnostic of?

Answer 63

Candida albicans

Question 64

If an india ink test is positive, what is the infectious agent?

Answer 64

Cryptococcus neoformans

Question 65

What is the commonly used agar in culturing fungi?

Answer 65

Sabouraud dextrose agar

Question 66

What are the major differences in culturing fungi as compared with bacteria?

Answer 66

Reduced temp DIfferent pH Longer time