Micro Ch. 12: Fungi

What are the general characteristics of fungi?

Chemoorganoheterotrophs: organic molecules as carbon and energy source
Aerobic or facultative anaerobes
Eukaryotes
Reproduce sexually + asexually and produce spores
Cell walls contain glycans, mannans, and chitin
Cell membrane contains ergosterol: antifungal target

What are the two morphologies of fungi?

Single cell yeast
Filamentous molds

How do yeast reproduce?

Reproduce through budding (blastospores)

Define mycology

scientific study of fungi

define hypha

single mold filament

define mycelium

mass of hypha

What is the difference between vegetative and reproductive mycelium?

Vegetative has no spores

Reproductive has spores

Define thallus

mold colony

Define blastospore

an asexual reproductive fungal spore produced by budding

Define septa

a cross-wall that divides the thread-like filamentous structures called hypha into distinct cellular compartments

Define septate

divided into compartments, or having one or more internal walls, partitions, or cross-walls

Define aseptate

a fungi with no septa

Define mycosis

any disease or health condition caused by a fungus (such as a yeast or mold) invading human or animal tissues
medical mycology

What is a dimorphic fungus?

Can grow as a yeast or mold depending on environmental conditions

What is a thermal dimorph?

a type of fungus that changes its physical shape based on temperature

At what temperature do thermal dimorphs grow as a mold?

Can grow as a mold in room temp

At what temperature do thermal dimorphs grow as a yeast?

Yeast at body temp

Why are thermal dimorphs clinically significant?

their ability to change shape is their primary virulence factor, allowing them to cause severe systemic infections in both healthy and immunocompromised individuals

Under what conditions do Candida albicans grow as a yeast?

Room Temp

Acidic pH

Absent serum

excess nitrogen

Under what conditions do Candida albicans grow filamentously?

Temp: 37C

pH: —-7
Serum present

limiting nitrogen

What are the general types of mycoses?

Allergic reactions

Fungal toxins

Superficial

Cutaneous

Subcutaneous

Systemic

What are examples of fungal toxins?

Ergotamine

Aflatoxins

What is a dermatophyte?

a group of specialized, mold-like fungi that require keratin to grow and survive

What types of infections do dermatophytes cause?

Hair, skin, nail infection

What enzyme produced by dermatophytes facilitates their ability to cause hair,

skin and nail infections?

Keritinase