Mycology Flashcards
What is mycology?
Study of fungi
Multicellular fungi are called…
molds
Unicellular fungi are called…
yeasts
Do fungi have a nucleus?
Yes
What is fungi’s primary purpose?
Decomposition
Are fungi eukaryotes or prokaryotes?
Eukaryotes
Describe sexual reproduction of fungi
Meeting of spores necessary
Describe asexual reproduction of fungi
Conidia: structures holding sterile spores land and immediately vegetate
How much of mold is actually visible?
Top 10%
Growing cells of mold make filaments called…
hyphae
Do the growing cells of mold have cell walls?
They may or may not
What are hyphae?
Tube (hair)-like extensions of the cytoplasm
Describe septate hypha
Hyphae are separated by walls called septa
What is a mycelial mat?
Fungal “mat” consisting of intertwined hyphae
aka mushrooms
Describe coenocytic hypha
Long hyphae cells, not separated into compartments
Hyphae grow from…
spores
In which direction does aerial hyphae grow?
What is an example of aerial hyphae?
Grows up
ie. mildew
Aerial hyphae is…
while vegetative hyphae is…
aerial is hydrophobic
vegetative is hydrophilic
What is thermal dimorphism?
The ability of a fungus to grow as yeast or mold depending on temperature
What temperatures does mold grow?
22 C
(colder than yeast)
What temperatures does yeast grow?
35-37 C
(warmer than mold)
How does yeast reproduce?
Asexually through budding
Fungi reproduce sexually and asexually via formation of…
spores
What is the purpose of fungi exospores compared to bacterial endospores?
Fungi exospores are for reproduction
Bacterial endospores are for survival
How are asexual spores produced and formed?
Produced via mitosis and cell division; formed by the hyphae of one organism
What is a conidiospore?
Asexual spore not enclosed in a sac
What is an arthroconidia?
Fragmentation of septate hyphae (an asexual spore)
What is a blastoconidia?
Asexual spore that buds off the parent cell
What is a chlamydoconidium?
Asexual spore within a hyphal segment
What is a sporangiospore?
Asexual spore enclosed in a sac
Conidia are arranged in…
chains
Fragmentation of hyphae result in formation of…
arthroconidia
Blastoconidia are formed from…
buds of parent cells
Chlamydoconidia are thick-walled cells within…
hyphae
Sporangiospores are formed within a…
sporangium
Sexual spores are comparable to…
mammalian reproduction
Sexual reproduction of fungi consist of fusion of…
nuclei from two opposite mating strains
What are the three phases of sexual reproduction of fungi?
- Plasmogamy
- Karyogamy
- Meiosis
What is plasmogamy?
Haploid donor cell nucleus (+) penetrates cytoplasm of recipient cell (-)
What is karyogamy?
+ and - nuclei fuse and form diploid zygote
What is meiosis?
Diploid nucleus produces haploid nuclei
Fungi grow better at a pH of…
5 (acidic)
How does fungal growth prefer sugar, salt, and osmotic pressure?
Prefers high sugar (uses it), tolerates high salt concentration, and is resistant to osmotic pressure
Can fungi grow without high moisture?
Yes, can grow in low moisture content such as deserts
What sort of things can fungi metabolize?
Complex carbohydrates, proteins, plastics, wood, skin, etc.
What is mycosis?
Any disease caused by a fungus (yeast or mold)
Which type of mycosis is most prevalent in the developed world?
Superficial mycoses
Name two examples of superficial mycoses
- Tinea capitis (scalp and eyebrows)
- Pityriasis (yeast dermatitis of chest and back)
Name two examples of cutaneous and mucocutaneous mycoses
- Ringworm
- Candidiasis
Name two examples of subcutaneous mycoses
- Sporotrichosis (puncture contamination)
- Zygomatic rhinitis
Name two examples of deep mycoses
- Coccidiomycosis (valley fever)
- Histoplasmosis
Which type of mycosis is rarely seen in the developed world?
Deep mycoses
What is the common cause of ringworm?
Close/abrasive contact
What is tinea cruris?
“Jock itch”
Fungal yeast based red scaling plaques on medial thighs and inguinal folds
What is the most common dermatophyte?
Tinea pedis
What is the etiology of tinea pedis?
Use of occlusive footwear
Tinea pedis presents with…
toe-web maceration (white mold)
How is tinea pedis treated?
Topically for a year
What is tinea unguium/ onychomycosis?
Fungal infection of nails either in foot or hand (more commonly feet)
How is tinea unguium treated?
Systemic treatment for 3 months
What is tinea capitis?
Superficial fungal infection of skin, scalp, eyebrows, and eyelashes, with a propensity for attacking hair shafts and follicles
What is the cause of sporotrichosis?
Sporothrix
Lives in soil and plants such as sphagnum moss, rose bushes, and hay
Histoplasmosis is caused by a fungus in the environment, particularly in soil/air that contains…
large amounts of bird or bat droppings
Do fungal pathogens need a host to complete their life cycle?
Most do not
True fungal pathogens are distributed in a predictable geographic pattern based on…
climate and soil
What are five fungal virulence factors?
- Thermal dimorphism
- Toxin production
- Capsules
- Adhesion factors
- Hydrolytic enxymes
Mycotoxins come from…
fungi
Which mycotoxin is carcinogenic?
Aflatoxin
Where is aflatoxin found?
Improperly stored peanuts
What is ergot?
Where is it found?
Hallucinogenic alkaloid toxin that affects dopamine
Found on improperly stored grain
What is psilocybin?
Where is it found?
Hallucinogenic toxin that affects cerebrum and sensory processing
Found in genus Basidiomycota
What is alpha - amanitin?
Where is it found?
Lethal toxin to hepatocytes; death occurs within 6 hours of ingestion
Found in the death cap mushroom
“Sick building” syndrome is caused by toxin production by…
stachybotrys chartarum
What are the effects of “sick building” syndrome?
Severe hematologic and neurologic damage
Where does “sick building” syndrome come from?
Water infiltration of building supplies or flood damage
