exam 1 Flashcards
Are fungi classified as eukaryotic or prokaryotic?
eukaryotic
what is the structural element that comprises a fungus?
hyphae
which class of fungi has non-septate mycelium?
zygomycetes
why are certain fungi classified as “Fungi Imperfecti”?
because it was once thought they didn’t sexually reproduce (perfect cycle is a reproducing one)
how does the function of reproductive mycelia differ from that of vegetative mycelia?
Veg. anchor fungus to the substrate (below surface) also have a digestive enzyme rep. project above the surface have spores
to which class do most pathogenic fungus belong too?
deuteromycetes
what term best describes the nutritional characteristics of fungi?
saprotrophic
are fungi aerobic or anaerobic
aerobic
what is the best single medium for the primary isolation of fungi?
sabouraud’s with dextrose
what is the purpose of corn meal agar?
nutritionally deprive organisms so sporulation (candida albicans)
how long should routine fungal cultures be held before being discarded?
4 weeks
what three things does the mounting medium lactophenol cotton blue do?
preserve fungal cultures reduce contamination of environment stain the hyaline fungal structures
when a systemic mycosis has spread to various organs, what term is used to describe it?
disseminated or systemic
what organism is best described as a thick-walled yeast cell with buds attached by a broad base?
blastomyces
which systemic fungus is always a yeast? (i.e. not diphasic)?
Cryptococcus neoformans
how is histoplasmosis acquired?
inhalation of spores and fungus is usually free living
name the five spcies of dimorphic (diplasic) fungi
blastomyces dermatididis histoplasma capsulatum paracoccidiodes braziliensis sporothrix schenckii coccidiodes imitis
which systemic fungus produces thick-walled yeast cells with multiple buds in tissue?
paracoccidiodes braziliensis
which fungus can be observed as a non-budding, thick-walled spherule containing endospores in a direct smear from the body?
coccidiodes imitis
which fungus produces spiny, tuberculate macrocondidia when cultured, but in the body can be seen as intracellular , yeast-like cells with a large vacuole in the cells of the RE system?
histoplasma capsulatum
cryptococcosis is usually seen as a disease of which body system?
pulmonary
which systemic fungus is the most fastidious (difficult to grow) in the laboratory?
histoplasma capsulatum
what systemic fungus causes San Jacquain Valley Fever?
coccidiodes
which systemic fungus causes South American blastomycoses?
paracoccidiodes braziliensis
which stain is best to use to demonstrate Cryptococcus neoformans in CSF?
india ink
which systemic fungus is endemic in Piedmont NC and can produce a primary pulmonary infection or a primary skin infection which resembles ringworm?
blastomyces dermatididis
which systemic fungus produces chains of arthrospores and can be confused with the saprophytic fungus geotrichum candidum?
coccidiodes
what is the macroscopic appearance of sporothrix scheneckii at 37 degrees?
Yeast: creamy white/tan smooth colonies
list several species of dematiaceous fungi
cladosporium phialophora fonsecaea
which subcutaneous infection produces yeast-like brown cells in clusters in the body?
chromomycosis
what is the most common cause of maduromycosis?
petriellidum boydii
what color are the granules that are frequently found in the pus of madurmycosis?
yellow to whitish
what fungus produces a tear-shaped conidia arranged in rosettes at 25 degrees and yeast cells when grown at 37 degrees and causes a disease common among gardeners which is referred to as “rose fever”?
sporothrix schenckii
name several species that can be responsible for chromomycosis
cladosporium carrion phialophora verucasa fonsecaea pedrosoi (f. compacta)
which organisms can cause mycetomas (fungal tumors)?
madurella mycetomatis
an organism which produces brown, branching septate hyphae would be classified as what type of fungus?
dematiaceous
what device can be used as an aid to select hairs infected with ringworm?
UV light fluorescent light
what type of hair infection is characterized by empty areas or tunnels where the hyphae have degenerated visible throughout the entire length of the hair?
favic
what combination of fungal media would be best to sue to culture the dermatophytes?
mycosel and sabourdas
which three genera of fungi all cause ringworm of the skin?
micropsorum trichophyton epidermophyton
what fungus appears velvety white on the front and mahogany on the reverse and will not grow on sterile unfortified rice grains?
microsporum audouinii
what fungus is the most common cause of ringworm in dogs and cats and is characterized by a canary yellow reverse and spiny, spindle-shaped macroconidia?
microsporum canis