Mycology Flashcards
Mycology refers to the study of ______
Fungi
Mycoses are ______
fungal infections.
Fungi are a diverse group of ____tic and ____tic eukaryotic organisms.
saprophy
parasi
Saprophytic means deriving nourishment from _____
dead organic matter
Fungi are approximately ____ in size
4um
CELL STRUCTURE of fungi
Cell membrane
-The fungal cell membrane contains ______ rather than the cholesterol found in mammalian membranes.
ergosterol
Cell wall of fungi
-The fungal cell wall consists primarily of ____ (not _____ as in bacteria)
-The fungal cell wall contains other polysaccharides as well, the most important of which is ____ , a long polymer of D-glucose.
chitin
peptidoglycan
β-glucan
Chitin is a polysaccharide composed of long chains of _____
N-acetylglucosamine.
Fungal characteristics
-Most fungi are obligate ____; some are ______; but none are ______
aerobes
facultative anaerobes
obligate anaerobes.
-only some fungi are chemoheterotrophs.
T/F
F
All fungi are
chemoheterotrophs means They require _______—hence their frequent association with _____
an organic source of carbon
decaying matter.
The natural habitat of most fungi is the ____ or _____.
An important exception is _____, which is part of the ________
soil
decaying organic matter
Candida albicans
normal human flora.
_______ is the site of action of antifungal drugs, amphotericin B & azole group.
Ergosterol
CLASSIFICATION OF FUNGI
Fungi are morphologically classified into:
*____-like fungi
*____-like fungi
mold
Yeast
mold-like fungi: e.g ____,____
*Yeast-like fungi e.g _________
Mucor, Rhizopus
Saccharomyces cerevisiae
Molds ( ______ fungi )
-The vegetative body of mold-like fungi is typically a ______ with ______
filamentous
mass of threads with many branches
Molds
Mass+ branches
This mass is called a ______, which grows by _______ and _____
-The branches/threads (____) are actually ____ cells that, in some fungi, are partitioned into segments (septate), whereas, in other fungi, the hyphae are uninterrupted by cross-walls (nonseptate).
mycelium
branching and tip elongation.
hyphae
tubular
In septate fungi, the cytoplasm of the hyphae is discontinuous.
T/F
F
Even in septate fungi, the septae are perforated so that the cytoplasm of the hyphae is continuous.
Molds
Their ____ on agar aids their diagnosis by their ______ and ______ produced
colony
appearance and pigments
YEASTS
-These fungi exist as populations of (single or double ?) , (connected or unconnected?) ,______ shaped cells.
-They reproduce by ______ known as _____.
Single
unconnected
spheroid
the formation of buds
blastospores
YEASTS
They are also called budding yeast
Why?
They appear with daughter cells attached
Yeasts colonies resemble bacterial colonies in appearance
T/F
T
Yeasts colonies resemble bacterial colonies in appearance and in consistency
Dimorphic fungi
-Some fungal species, especially those that cause ____, are dimorphic, being yeast-like in one environment and mold-like in another
-This is usually dependent on _____ and as such, they are also called ____ .
systemic mycoses
temperature
thermally dimorphic
Dimorphic fungi
Molds in the environment (_______ phase) __-__C.
-Yeast (________ phase) __C.
-Examples; ________,______,______
saprophytic ; 25 – 27
parasitic/pathologic; 37
Histoplasma capsulatum, Blastomyces, Talaromyces marneffei
Fungal reproduction
-______ is the principal means by which fungi reproduce and spread through the environment.
Sporulation
Fungal sporulation
Spores can be generated only asexually
T/F
F
Spores can be generated either asexually or sexually
Fungal sporulation
the spores are metabolically active
T/F
F
Metabolically dormant
Fungal spores are protected cells with (thin or thick ?) cells walls and (easy or difficult?) to destroy.
They also tend to be released in (small or large?) amounts.
Thick
Difficult
Large
Asexual Sporulation:
-Asexual spores (aka _____ ) are formed by (mitosis or meiosis?) in or on specialized hyphae (_______ )
conidia
mitosis
conidiophores
The color of a typical fungal colony seen on bread, fruit, or culture plate is caused by the _____
conidia.
Conidia can be easily detached from their underlying mycelia
T/F
T
Some important conidia include:
*_______
*________
*_______
*_________
Arthrospores
Chlamydospores
Blastospores
Sporangiospores
Arthrospores, which arise by ________________ and are the mode of transmission of __________
fragmentation of the ends of hyphae
Coccidioides immitis
Chlamydospores, which are ____ shape, (thin or thick?)-walled, and quite resistant
Round
Thick
Blastospores, which are formed by the _______
budding process
C. Albicans, can form multiple buds that _____, thus producing ________ called ______, which can be used for identification
do not detach
sausagelike chains
pseudohyphae
Sporangiospores, which are formed within a sac ( _____ ) on a stalk by molds such as ______,___
sporangium
Rhizopus and Mucor
Sexual Sporulation:
-Some fungi reproduce sexually by _____ and forming ______ (e.g., ____spores, _____spores, and ____spores).
mating
sexual spores
zygospores, ascospores, and basidiospores
Zygospores are (single or double ?) (small or large?) spores with (thin or thick?) walls
Single
Large
Thick
ascospores are formed in a sac called ____
ascus
basidiospores are formed __ternally on the ___ of a pedestal called a _____.
ex
tip
basidium
Laboratory identifications of fungi
-__________ examination,
-_______ of the organism
-_______ tests
- _______Tests
Direct microscopic
Culture
DNA probe
Serologic
Direct examination
-Direct microscopic examination of clinical specimens.
-The specimen is either treated with _______ to dissolve tissue material, leaving the alkali-resistant ___ intact, or stained with special fungal stains.
10% potassium hydroxide (KOH)
fungi
culture
-Fungi are frequently cultured on _____
Sabouraud’s agar
Function of Sabouraud’s agar
It facilitates the appearance of the slow-growing fungi by inhibiting the growth of bacteria in the specimen
MYCOSES
They may be classified into;
-_________
-_______
-________
-_______
Cutaneous (Superficial)
Subcutaneous
Systemic
Opportunistic
Cutaneous (Superficial) MYCOSES:
Also called _____, these common diseases are caused by a group of related fungi, the ———.
They majorly affect ____,____,___
dermatophytoses
dermatophytes
hair, nails , skin
Dermatophytes fall into three genera, each with many species:
Mention the genera
Trichophyton, Epidermophyton, and Microsporum
Which of these doesn’t affect nails
Trichophyton, Epidermophyton, and Microsporum
Microsporum
Subcutaneous
Subcutaneous mycoses are fungal infections of the _____,_______,and ______
Examples are _______ and ——-
dermis, subcutaneous tissue, and bone.
Sporotrichosis and Chromomycosis.
Systemic
Fungi may systemically affect the
_________ or _______
Examples include ——-,——-,——
immunocompetent or immunicompromised
Coccidioidomycosis, Histoplasmosis, and Blastomycosis
Opportunistic
Opportunistic mycoses afflict ______ or _______ individuals but are rare in ____ individual
-Important examples include ______,_____
debilitated or immunocompromised
healthy
Candidiasis and cryptococcosis.
Yeasts produce
endotoxins
T/F
F
Yeasts produce exotoxins
T/F
F
Mycotoxins:______ produced by fungi e.g aflatoxin of Aspergillus flavus
Mytoxicosis: fungi ______
toxins
intoxication
Fungi
-are (autotrophic or heterotrophic?) eukaryotes
-Morphologically categorized into ____ (___-celled) and ________ (______) forms.
Fungi are like mammalian cells, that is, they are eukaryotic but their cell membranes differ in that they contain ______, while mammalian cells contain _______.
heterotrophic
yeast; single; filamentous; mold
ergosterol
cholesterol
Over 5 million species of fungi are estimated to be in existence with only ~_____ species accounting for disease in humans.
300
Fungal cell structure
fungi cell wall is made up of ____,______ and _____________.
Size-diameter
__ um
_______ dimorphism.
Metabolism.
chitin, mannan; both alpha - and β-glucans
4
Thermal
______ is the site of action of antifungal drugs, amphtericin B & azole group
Ergosterol
_______,______,_______,________, and _________ fungi such as Histoplasma capsulatum and Talaromyces marneffei remain the main fungal pathogens responsible for the majority cases of serious fungal disease.
_____,_______, and ________ are always lethal unless diagnosed and treated early and correctly.
Aspergillus, Candida, Cryptococcus species, Pneumocystis jirovecii, endemic dimorphic
Cryptococcal meningitis, pneumocystis pneumonia, and disseminated histoplasmosis
Most fungi are ________, some are ______, but none are ______
obligatory aerobes
facultative anaerobes
obligatory anaerobes.
Not all fungi require a performed organic source of carbon –association with decaying matter.
T/F
F
All !!!
Natural habitat of fungi is the _____ except for ______ which is part normal flora of ______
environment
Candida spp
humans
Fungi causes diseases primarily in humans if they are ______ OR if the fungal _________ is ______
immunosuppressed
spores (load/burden) is much.
Common immunosuppression that predispose to mycoses are ____,_____,_____,______,_____,______, and ________etc.
diabetes, HIV/AIDS, long term steroid use, cancers, cancer treatments, stem cell and solid organ transplant
Filamentous fungi
The basic morphological elements of filamentous fungi are _________, which intertwine to produce a ______
Colonies are (weakly or strongly?) adherent to the medium and unlike most bacterial colonies cannot be ______
Hyphae can be ______ or _____
Their _______ on _____ aids their diagnosis by their appearance and _______ produced
long branching filaments or hyphae
mass of filaments or mycelium
Strongly ; emulsified in water
septate or non septate
colony on agar; pigments
YEAST
These occur in the form of ______ or _____ bodies which reproduce by the formation of buds known as ______.
They are also called _______, with _______ cells attached
round or oval
blastospores
budding yeast; daughter
Yeasts colonies resemble bacterial colonies in appearance but not in consistency.
T/F
F
Yeasts colonies resemble bacterial colonies in appearance and in consistency.
Dimorphic fungi
Molds in the environment (______ phase) __-__C.
Yeast (_______/______ phase) ___C.
saprophytic; 25-270C
parasitic/pathologic; 370C
Dimorphic fungi
In human body they are _____
yeast
Dimorphic fungi
Examples; ________,_______,_____
Histoplasma carpsulatum, Blastomyces, Talaromyces marneffei
Mycoses( fungal infections)
Can be :
______
______
______
_____
Superficial
Subcutaneous
Systemic
Opportunistic
Fungi wall is made of 3 things
Chitin
Glucan
Mannan
Mycetoma
______ mycoses
Subcutaneous
Sporotrichosis
________ mycoses
Subcutaneous
Chromomycosis
________ mycoses
Subcutaneous
Trichophyton
________ mycoses
Superficial
Epidermophyton
________ mycoses
Superficial
Microsporum
________ mycoses
Superficial
Histoplasmosis
________ mycoses
Systemic
Blastomycosis
________ mycoses
Systemic
Coccidiodomycosis
________ mycoses
Systemic
Cryptococcosis
________ mycoses
Opportunistic
Candidiasis
________ mycoses
Opportunistic
Coccidioides immitis
______ form of sporulation
Arthrospores
Candida albicans
______ form of sporulation
Blastospores
Rhizopus
______ form of sporulation
Sporangiospores
Mucor
______ form of sporulation
Sporangiospores
Saccarhomyces cerevisae
Yeast or mold?
Yeast
Mucor
Yeast or mold
Mold
Rhizopus
Yeast or mold
Mold
__toxin of _______
Aflatoxin
Aspergillus Flavus
Most fungi are abundant in the ecosystem.
T/F
T
Over _____ species of fungi are estimated to be in existence with only ___ species accounting for disease in humans.
5 million
~300
PCR is used to ____
Amplify DNA
Serologic tests is used to ______
Identify the Antigens or antibodies
In _____ mycoses, an injury has to occur for penetration, infection, and spread to occur
Subcutaneous
Imperfect fungi are fungi that _______
Do not undergo sexual reproduction
_________ prevents the growth on bacteria in sabouraud’s dextrose agar
10% chloramphenicol
Some Fungi are edible
T/F
T
