Mycology Flashcards
are fungi pro or eukaryotic
eukaryotic
uni vs multicellular fungi
uni: yeast
multi: mold and mushrooms
how do fungi get nutrition
non-photosynthetic heterotrophs
requires organic substrates to get its carbon for growth
- performs extracellular digestion then absorbs nutrients
saprophytic
exists in the environment; lives in dead or decaying organic matter (ex. soil)
parasitic
exists within a host
are fungi motile
no
what kind of environment do fungi thrive in
wet/humid
room temperature
acidic pH
are fungi aerobic or anaerobic
aerobic
except yeast - facultative anaerobe
what are predisposing factors for fungal infection
- prolonged antibiotic therapy
- immunosuppression
- immaturity/malnutrition
- endocrine disorders
yeast
unicellular, oval or spherical cells that are larger than most bacteria
molds
multicellular mycelium
hyphae
tubular structure of the growing mycelium
septate vs non-septate
hyphae separated by cross-walls vs continuous hyphae with no separations
dematiaceous fungi
dark pigmented molds
hyaline fungi
non-pigmented molds
conidiophores
hyphae that produce conidia for asexual reproduction
sporangiophores
hyphae that produce spores for asexual reproduction
conidia/spores
infective stage of mold
- environmentally resistant
released when sporangium ruptures
- allows for aerial dissemination
dimorphic fungi
fungi that change from mold to yeast depending on environment
ex. thermal
- mold at room temp
- yeast at warm temp
sexual vs asexual fungal reproduction
sexual: rare; fusion of haploid nuclei then meiosis
asexual: most common; division by mitosis
mechanisms of asexual reproduction in fungi
- sporulation
- hyphae fragmentation
- budding (yeast only)
classification of fungal disease
- superficial (dermatophytosis, dermatomycoses)
- subcutaneous
- systemic
capsule
compact capsule or external coating composed of polysaccharides that aid in adherence or clumping
protects fungi in the host or in the environment
- can be antigenic and anti-phagocytic
fungal cell wall
lies outside cytoplasmic membrane
composed of polysaccharide chains cross-linked with proteins and glycoproteins
- contains chitin
- different fungal species have common polysaccharides in cell wall
fungi cytoplasmic membrane
bilayer membrane that contains sterols (ergosterol, zymosterol)
NOT cholesterol like in mammals
what is the most common immune response to fungi
cell mediated formation of granulomatous lesions
- type IV hypersensitivity
antibodies not effective
what must the media used for propagating fungi contain
carbon source
cutaneous mycoses
- dermatomycoses
- dermatophytoses
dermatomycoses
opportunistic infections of skin or mucocutaneous junctions from overgrowth of fungi
ex. malassezia pachydermatis and candida albicans
malassezia pachydermatis
yeast
causes otitis externa and dermatitis in dogs
candida albicans
yeast - endogenous; can overgrow esp. in immunocompromised hosts
inhabits mucous membranes of animals and birds
causes yellow/gray plaques and ulceration
dermatophytoses
subset of dermatomycoses caused only by dermatophytes
invasion and destruction of keratinized structures
- superficial skin, hair, feathers, hooves, claws, etc
ex. ringworm
how to diagnose dermatophytosis
hair plucks
skin scrapings on edge of lesion
chytridiomycosis
infectious disease of amphibians casued by batrachochytrium dendrobatidis
affects skin –> decreased ability to breathe, hydrate, osmoregulate
white nose syndrome
infectious disease of bats caused by pseudogymnokscus destructans
