Mycology Flashcards by Iseoluwa Ojo

Mycology refers to the study of ______

Fungi

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Mycoses are ______

fungal infections.

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Fungi are a diverse group of ____tic and ____tic eukaryotic organisms.

saprophy

parasi

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Saprophytic means deriving nourishment from _____

dead organic matter

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Fungi are approximately ____ in size

4um

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CELL STRUCTURE of fungi

Cell membrane
-The fungal cell membrane contains ______ rather than the cholesterol found in mammalian membranes.

ergosterol

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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

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Chitin is a polysaccharide composed of long chains of _____

N-acetylglucosamine.

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Fungal characteristics

-Most fungi are obligate ____; some are ______; but none are ______

aerobes

facultative anaerobes

obligate anaerobes.

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-only some fungi are chemoheterotrophs.

T/F

All fungi are

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chemoheterotrophs means They require _______—hence their frequent association with _____

an organic source of carbon

decaying matter.

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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.

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_______ is the site of action of antifungal drugs, amphotericin B & azole group.

Ergosterol

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CLASSIFICATION OF FUNGI

Fungi are morphologically classified into:

*____-like fungi
*____-like fungi

mold

Yeast

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mold-like fungi: e.g ____,____

*Yeast-like fungi e.g _________

Mucor, Rhizopus

Saccharomyces cerevisiae

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Molds ( ______ fungi )
-The vegetative body of mold-like fungi is typically a ______ with ______

filamentous

mass of threads with many branches

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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

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In septate fungi, the cytoplasm of the hyphae is discontinuous.

T/F

Even in septate fungi, the septae are perforated so that the cytoplasm of the hyphae is continuous.

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Molds

Their ____ on agar aids their diagnosis by their ______ and ______ produced

colony

appearance and pigments

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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

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YEASTS

They are also called budding yeast

Why?

They appear with daughter cells attached

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Yeasts colonies resemble bacterial colonies in appearance

T/F

Yeasts colonies resemble bacterial colonies in appearance and in consistency

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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

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Dimorphic fungi

Molds in the environment (_______ phase) __-__C.
-Yeast (________ phase) __C.

-Examples; ________,______,______

saprophytic ; 25 – 27

parasitic/pathologic; 37

Histoplasma capsulatum, Blastomyces, Talaromyces marneffei

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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

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

Yeasts produce exotoxins T/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

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