Mycology Flashcards
multicellular fungi are called ____
molds
unicellular fungi are called ____
yeasts
fungal characteristics
- eukaryotes (have nucleus)
- simple plants
- decomposers
- sexual/asexual reproduction
how do spores reproduce?
sexually (meet w other spores)
how do conidia reproduce?
asexually (land on any surface)
hyphae
tube (hair)-like extensions of cytoplasm
mycelium
fungal “mat” consisting of intertwined hyphae
(AKA mushrooms)
name 3 ways that hyphae can grow?
- septate hypha (walls)
- coenocytic hypha (no walls between)
- growth of hypha from a spore
aerial hyphae grow ____
upward
vegetative hyphae grow ____
flat/straight across
thermal dimorphism
ability possessed by a fungus to grow as a yeast or as a mold depending on temperature
what temperature does yeast grow at?
35-37*C (body temp)
what temperature does mold grow at?
22*C (room temp)
yeast is a ____ fungus that reproduces ____ via ____
unicellular
asexually
budding (push cytoplasm into wall)
fungi reproduce via the formation of ____ that detach from the parent and germinate into a new mold
spores
asexual spores are produced via ____, and are formed by…
- mitosis & cell division
- hyphae of one organism
conidiospore
not enclosed in a sac
arthroconidia
fragmentation of septate hyphae
blastoconidia
buds of the parent cell
chlamydoconidium
thick-walled cells/spore within a hyphal segment
sporangiospore
enclosed in a sac (within a sporangium)
conidia are arranged in ____
chains
how are sexual spores formed?
fusion of nuclei from 2 opposite mating strains
3 phases of sexual reproduction
- plasmogamy
- karyogamy
- meiosis
plasmogamy
haploid donor cell nucleus (+) penetrates cytoplasm of recipient cell (-)
karyogamy
+ and - nuclei fuse and form diploid zygote
meiosis
diploid nucleus produces haploid nuclei (sexual spores)
nutritional adaptations of fungi
- grow better at pH of 5
- grow in high sugar and salt concentration; resistant to osmotic pressure
- can grow in low moisture content
- can metabolize complex carbs
mycosis
any disease caused by a fungus (yeast or mold)
examples of superficial mycoses
- tinea capitis (scalp & eyebrows)
- pityriasis (yeast dermatitis of chest & back)
examples of cutaneous and mucocutaneous mycoses
- ringworm
- candidiasis
examples of subcutaneous mycoses
- sporotrichosis (puncture contamination)
- zygomatic rhinitis
examples of deep mycoses
- coccidiomycosis (valley fever)
- histoplasmosis
what type of clothing causes yeast pityriasis?
wick-wear (‘breathable’) -> yeast remains in clothing
tinea cruris is also called ____
jock itch
what is tinea cruris?
red scaling plaques on medial thighs and inguinal folds
tinea cruris may be spread from ____
tinea pedis (athlete’s foot)
what is the most common dermatophyte?
tinea pedis
etiology of tinea pedis
use of occlusive footwear, presents with toe-web maceration (mold)
what is tinea unguium (onychomycosis)?
fungal infection of the nails of either feet or hands
what is tinea capitis?
superficial fungal infection of the skin of scalp, eyebrows, and eyelashes, with a propensity for attacking hair shafts and follicles
sporotrichosis is also known as ____
rose gardener’s disease or rose gardener’s thumb
what causes sporotrichosis?
sporothrix
(fungus throughout the world in soil and on plant matter such as sphagnum moss, rose bushes, and hay)
where does histoplasmosis fungus live?
- soil containing large amounts of bird or bat droppings
- in US: central and eastern states, especially around Ohio and Mississippi river valleys
- parts of central & south america, africa, asia, australia
do fungal pathogens require a host to complete their life cycle?
no, most do not
true fungal pathogens are distributed in a predictable geographic pattern based on ____ and ____
climate and soil
valley fever (coccidiodomycosis) can spread beyond the lungs to the bloodstream, and eventually the brain, causing ____
meningitis
fungal virulence factors
- thermal dimorphism
- toxin production
- capsules
- adhesion factors
- hydrolytic enzymes
name 4 examples of mycotoxins
- aflatoxin
- ergot
- psilocybin
- a-amanitin
aflatoxin
- carcinogenic
- found on improperly stored peanuts
ergot
- hallucinogen
- alkaloid toxin that affects dopamine
- found on improperly stored grain
psilocybin
- hallucinogen (magic mushrooms)
- affects cerebrum and sensory processing
- found in genus Basidiomycota
a-amanitin
(death cap mushroom)
- lethal to hepatocytes
- death occurs within 6hrs of ingestion
“sick building” syndrome
- caused by toxin production by Stachybotrys chartarum
- severe hematologic and neurologic damage
- water infiltration of building supplies or flood damage
