Basic concepts of mycology Flashcards
fungi are eukaryotic because?
they possess true nucleus, nuclear membrane, and mitochondria
characteristics of yeasts
- single, vegetative cells (unicellular)
- moist, creamy, opaque or pasty colonies on media
yeasts reproduce through ___ which involves maturation of the mother bud that can independent to blasticonidium
budding
general considerations for the identification of molds
- growth rate
- colonial morphologic features
- microscopic morphologic features
how do we differentiate fungi from other microorganisms?
fungi are eukaryotic while bacteria are prokaryotes
why do fungi lack antibiotic susceptibility?
you cannot use antimicrobial agents, instead antifungal agents.
fungi are ___ bcos they can acquire nutrients from their environment
saprophytic
environmental requirement of fungi
OBLIGATE AEROBES
- they grow best at neutral pH and moisture is necessary for their growth.
t or f: most fungi survive in dry conditions
true
yeast usually appear?
tan to yellowish
term refers to the daughter cells of yeast
blastoconidium
in yeast, the parent cell is able to give the genetic material to the daughter cells through the process of?
mitosis
molds are also known as?
filamentous fungi
what makes it unique in the reproduction of molds?
base on their structure
Moist, creamy, opaque or pasty colonies
yeast
fluffy, cotton, wooly or powdery colonies
molds
general considerations for the identification of molds
- growth rate
- colonial morphologic features
- fluffy, cotton, wooly or powdery colonies
- formation of mycelia
mycelias that grow on top which tend to support the reproductive structures
aerial mycelia
mycelia that grow on the bottom
vegetative mycelia
mycelia that can be either aerial or vegetative
hyphae
made up of many long strands of tube-like structures
**hyphae
what is the best way to categorize the molds in examination of hyphae?
look for septate or septation
has frequent cross walls, perpendicular to outer walls of hyphae, and looks like a separation in between
septate
irregular intervals that can be found in hyphae
sparsely septate
term refers for the absence of cross walls or segments
aseptate
reproductive structures of molds
conidia
the structure that supports the conidia is ____
aerial mycelia
term refers to a furrowed or convoluted appearance of fungi in the media
verrucose
appearance of fungi in media:
slightly raised in the center
umbonate
what is rugose?
furrows radiate out from the center
slow growers fungi tend to grow?
11 - 21 days
intermediate growers fungi
6 - 10 days
growth rate for rapid growers fungi
5 days or less
pigmentation of fungi can either be?
hyaline of phaeoid
hyaline pigmentation refers to a?
nonpigmented or lightly pigmented
what is phaeoid?
- darkly pigmented
- melanized (dematiaceous)
true or false: pigmentation can only be seen with stains
false, usually seen WITHOUT stains
WHITEY SCALEY: hyaline or phaeoid?
phaeoid
how can we differentiate the type of diseases and causes of fungi?
through their pigmentation
stains of fungi
- Gomori methylene
- Fontana-Masson
black appearance which is brought by the stain?
Gomori methylene
using the Fontana-Masson stain, hyaline is usually seen in color?
pink to red
using the Fontana-Masson stain, phaeoid is usually seen in color?
brown
texture in loose, high aerial mycelium
cottony
low aerial mycelium has a ___ texture
velvety
texture which refers to a dense powdery resembling sugar granules
granular
describe the glabrous texture
smooth surface with no aerial mycelium
high aerial mycelium that appears slightly matted brown
wooly
fungi which tend to terminally change their phases
dimorphic fungi
mold and yeast phase
dimorphic fungi
temp for the dimorphic fungi mold phase
25-30C
temp for the yeast phase in dimorphic fungi
35-37C
both yeast and molds forms in the same culture
polymorphic
in culture, molds present as ____. they have mycelia observed
filamentous
fungi in the form of molds reproduce asexually or sexually?
both
imperfect fungi is also known as?
asexual or anamorph
asexual fungi are carried out by?
Conidiogenous cells
these cells produce the spores
an endogenous type of spores which has a sac-like structure and they tend to spread spores inside
sporangiospores
production of spores can be?
endogenous or exogenous
term refers to the production of spores which would spread outside
exogenous - conidiophore
formation of conidia is derived from?
hypha
- cells that contains genetic material having a fruit structure
- it holds the protein structures
conidiogenous cells
2 kinds of conidiogenous cells
phialides and annelides
phialides
base-like structure
the structure that holds phialides are?
conidiosphore
mycelia are hyphae and are the ones that support ___.
conidia
Without hyphae, conidiophore, and phialides, you will have ____
no conidia for reproduction
type of conidia having spore’s formation like fragmentation
arthroconidia
2 types of conidium
- microconidia
- macroconidia
a unicellular, round, elliptical conidia
microconidia
a multiseptated and club or spindle shaped conidia
macroconidia
a saclike structure produced at the tip which reproduce asexually
sporangiospore
Asexual spores (sporangiosphore) are produced through?
sporangium
sexual spores are?
perfect fungi
fungi that reproduces sexually
teleomorph
asexual forms of the same fungus
synanomorphs
zygospores is a
sporangiospore
ascospores is a
conidia
fungi phyla
- ascomycota
- basidiomycota
- subphylum mucoromycotina
a group of fungi where there is no mode of reproduction or they have no means of producing sexually (imperfect fungi)
deuteromycota
- subphylum mucoromyctoina
- reproduce asexually
mucorales
(sporangiospores, sporangium, sporangiophore)
ascomycota (ascospores) reproduction
sexual
refers to the basidiospores or basidia which reproduce sexually
basidiomycota
50% of all named fungi belongs to this phylum
ascomycota
it has a distinct characteristic having a clamp connections
BASIDIOMYCOTA
biosafety cabinet for fungi
class II biosafety cabinet
specimen for diagnosis of fungi can be
- respiratory tract specimen (sputum, induced sputum, tracheal aspiration, bronchial washings, broncho alveolar lavage)
- CSF
- blood
- eye (corneal scrapings)
- hair
- skin
- nails
- vaginal
- urine
- tissue, bone marrow, and sterile body fluids
most common specimen in identifying yeast and hyphal elements
urine
agent used to liquefy sputum
N-acetyl-L-cysteine
storage req for respiratory tract specimen and the media used
room temp - processed within 2 hrs
refrigeration (4C) - delay
media: nonselective and media with antibacterial agents
storage req for CSF
should be processed immediately
- room temp or 30C
preparation: centri and filtration
blood cultures (automation) for blood specimen
BACTEC
ALERT
VersaTREK
temp req and duration for a blood sample
temp: 30C
duration: 21 days
a special container in which the wbc and rbc are lysed and centrifuged to get concentrates
isolator
storage and media used for corneal scrapings
media: non-inhibitory
storage: room temp
a common identifying method used for hair sample
wood lamp UV of >365 nm
a sample that requires aseptic technique
hair
incubation temp for a hair sample
22 - 30C
vaginal discharge should be?
- submitted w/in 24 hrs
- use of transport swab
- incubate 30C for 7 dats
- media: selective and inhibitory
a sample that uses a heparizined syringe and isolator tubes
bone marrow
used for direct microscopic examination of specimen
- KOH preparation
- KOH with calcoflour white
- India ink
- Tissue stains (periodic acid schiff and mason-fontana stain)
KOH preparation is used for samples like
skin, hair, nails, and tissue
breaks down keratin
10% - 20% potassium hydroxide solution
can be used with KOH, has a greater breakdown of debris, no heat required
Dimethyl sulfoxide (DMSO)
binds to polysaccharides in chitin walls of fungus and needs a fluorescent microscope
KOH with calcoflour white
+ result of KOH with calcoflour white
fluoresce apple green or blue-white
used to examine CSF
INDIA INK
- Encapsulated yeast C. neoformans
- Yeast: Clear w/ Halo (capsule
- a stain for detection of fungi
- hyphae of molds and yeast can be readily distinguished
Periodic Acid Schiff (PAS) Stain
for the examination of melanin pigment in fungal cell walls
Masson-Fontana stain
tease mount uses two teasing needles and the?
Lactophenol Cotton Blue (LPCB)
- Lactic acid, Phenol and dye – kills, preserves and stains
organisms
+ result for tease mount
blue appearance
The method of getting the hyphae or mycelia from the fungus
cellophane tape method
common or routine primary culture media for the initial isolation of pathogens and saprobes
Sabouraud dextrose agar
antibiotic agent that inhibit * insignificant fungal contaminants*
Cycloheximide
antibiotic agent that inhibit bacterial growth
Gentamicin or Chloramphenicol
a media that enhance the growth of dimorphic fungi
Brain-heart infusions (BHI) w/ 5% to 10% sheep blood
agar for the Isolation and presumptive identification of yeast and filamentous fungi
chromogenic agar
agar that allows identification of pathogenic yeast by examining the microscopic morphology of inoculum growth
Cornmeal agar
a test for yeast
principle: Grown with serum or plasma at __
Ability to form hyphae
germ tube
principle: Grown with serum or plasma at 35c
positive for germ tube
Candida albicans
incubation requirements for culture(temp, duration)
temp: 30C
duration: 21 - 30 days
cultures should be examined at least 3x weekly
