Exam 1: labs 1-3 Flashcards
How long does it take fungal organisms to grow on culture
2-4wks
what is the first culture medium used to ID fungi
sabouraud dextrose
most fungi will grow at __temperature in the __, with moderate levels of __
room temperature, in the dark, with moderate levels of humidity
Yeast or mold: single celled fungi with a spherical or oval shape
yeasts
what is the most common means of reproduction for yeasts
budding
cryptococcus or blastomyces: encapsulated, narrow based budding yeast
cryptococcus
cryptococcus or blastomyces: dimorphic fungus, broad based budding in yeast form
blastomyces
what is the primary virulence factor for yeast
capsule- evade alveolar macrophage phagocytosis
mold or yeast: fungi growing in strings of long, multicellular filaments
mold
a single filament of mold is known as a __
hypha
mat of hyphae is known as __
mycelium
hyphae can be categorized as __ if individual cells in hyphae are separated by walls or __ if hypha is continuous
septate, non-septate
what type of asexual reproduction has spores contained within a sac-like container
sporangiospores
what type of asexual reproduction has spores not enclosed within spore-bearing sac
conidida
some fungi are dimorphic which means what
can grow as yeast or mold depending on environmental conditions. Yeasts at 37 degrees C, and mold at 25
What dye is used for tape preps
lactophenol cotton blue
describe how high performance liquid chromatography works to identify mycotoxins
samples placed in a matrix and can determine which mycotoxin it is based on its time to move through matrix
aflatoxin is produced by ___ and can cause severe __
aspergillus Flavus, liver disease
ochratoxin produced by ___ and ___ and are __ and ___
penicillium and aspergillus, nephrotoxic and carcinogenic
citrinin is produced by ___ and __ and are __-
penicillium and aspergillus
Nephrotoxic
fumonisins and zearalenone are produced by __ which causes __
fusarium
Causes CNS disturbances and hormonal imbalances
penitrem a is produced by __ and ___ and cause ___
penicillium and aspergillus
Neurologic imbalances
gliotoxin is produced by ___ and causes ___
aspergillus, immunosuppression
what type of samples a are typically collected for mycology and virology
skin Or hair samples
if you are submitting samples for virus isolation like swabs or fluid it is important to place it in an appropriate viral transport media. This liquid media helps prevent __, stabilizes ___ and limits ___
prevent bacterial growth, stabilizes pH, limits enzymatic degradation
if you are submitting samples for PCR or rt-PCR it is best to place in appropriate viral transport media which prevents ___
enzymatic breakdown of viral DNA and more importantly RNA which is highly fragile
it is best to send PCR or rt-PCR samples how
chilled or frozen, overnight
if you are collecting samples during surgery or necropsy for fluorescent antibody testing it is best to ___these samples and get to lab within __
freeze or chill, 24hrs
what technique can be used at everyday clinics to identify suspected fungal infection
diff-quick stain
what wet mount technique can quickly identify dermatophytes and how does it work
KOH- place sample and a few drops of 10% KOH on slide which digests away keratin and makes fungal structures in hair, skin or toenails easier to see. Allow to sit for several minutes, then heat and cover with coverslip
What species does wood lamp detect
microsporum spp and malasseiza
how does woods lamp work
will fluoresce green as a result of porphyrins produced by agents
describe a dermatophyte test medium
culture plate with two sides
1. One side with SDA- permit fungal agents to grow
2. SDA with cyclohexamide to restrict growth of environmental fungi, restrict bacterial growth and a phenol red pH indicator
Dermatophytes produce alkaline byproduct and will turn agar from yellow to bright red
t or f: not all growth that runs the DTM plate red is a dermatophyte
true
t or f: all whitish colonies on DTM plates are dermatophytes
false
t or f: not all dermatophytes turn the DTM plate red
true
what color will Candida albicans turn on chromagar plate
green
what color will candida tropicalis turn on chromagar plate
steel blue
what color will candida krusei turn on chromagar plate
rose, fuzzy
what color will malasseizia pachydermatis turn on chromagar
pink/purple
what is one of the only species to produce a germ tube
Candida albicans
what is purpose of germ tube
Virulence factor- allows organism to invade mucous membranes
what two stains are used to highlight fungal organisms in tissue sections
- Gomori methenamine silver (GMS)
- Periodic acid shiff (PAS)
how does GMS stain work
- Apply chromic acid which oxidizes fungal cell wall polysaccharides to produce aldehydes
- Aldehydes reduce methenamine silver nitrate to metallic silver
- Fungal cell walls brown/black color
- Counterstain with fast green
how does PAS stain work
- Use chromic acid to reduce cell wall polysaccharides to aldehydes
- Counterstain with fuschin to stain purple
how do you do IHC
- Pretreat sample to expose antigens
- Incubate with primary antibody that is labeled with enzyme that produces a color change when treated with substrate
- Incubate with primary antigen
- Wash slides and treat with substrate- ACE for red, DAB for brown color
Monoclonal antibodies are more ___whereas polyclonal antibodies are more ___
specific, sensitive
the agar gel immunodiffusion assay is technique used to detect ___
antibodies against some agents in animal serum
how does AGID work
place antigen of interest in center well and then in surrounding wells place patient serum. If the antibodies present in patient serum match antigen in well then a white line/precipitate will form between them
Are AGID and immunohistological stains qualitative or quantitative
Qualitative
AEC primary antibody stain turns antigens what color
red
DAB primary antibody stain turns antigens what color
brown
