L37- Fungi Flashcards by Connor Patrick

unicellular fungi are known as (1)

multicellular fungi are known as (2)

1- yeast

2- molds (+ mushrooms)

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describe mushrooms in relation to fungal infections

mushrooms are the ‘fruiting bodies’ of Molds

- mushrooms are not found in fungal infections

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(1) are fungi that decompose dead things

(2) are fungi that invade and decompose living material

1- saprophytes
2- parasitic fungi
(note- some parasitic fungi will do both)

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fungal cell walls are very different than bacterial cell walls and act as (1) and (2) while being simultaneously (3)

1- pressure barrier
2- defensive structure
3- highly antigenic

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list the components of fungal cell wall

-chitin
-β (1,3) & β (1,6) glucans
-mannose modified proteins
-GPI (glycosylphosphatidylinositol) anchored proteins
-ergosterol (instead of cholesterol)
NOTE- host cell receptors and complement interact with these external proteins

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multicellular fungi connect together via (1)- tangled masses of (1) are called (2)

1- hyphae

2- mycelia

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describe the difference between sepate and aseptate

Septate: cell walls between neighboring cells, perforated for mitochondria and nuclei to migrate along hyphal strand

Aseptate: aka coenocytic, no cell wall, only single plasma membrane surrounding multi-nucleated cells

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fungal nuclei are (haploid/diploid)

haploid

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define dikaryon

fungal cell with two haploid nuclei (NOT diploid) during generation of zygote

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describe conditions and status of dimorphic fungi in animal habitat

inc Temp (35-40), reduced O2, suboptimal nutrients
parasitic, yeast phase
reproduction thru budding or endospores

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describe conditions and status of dimorphic fungi in natural habitat

dec Temp (<30), optimal O2, inc nutrients
saprobic (free-living), mycefial phase
reproduction thru sporulation

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Asexual reproduction of fungi can be occur equally through (1) or unequally through (2). Asexual spores are known as (3) and are formed directly from (4).

1- mitosis
2- budding
3- conidia
4- hyphae or specialized hyphal structures

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Sexual reproduction of fungi occurs when (1) fuses to produce (2) which then produces (3)

1- haploid gametes
2- transient diploid zygote
3- haploid spores

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what are the portals of entry for fungi

respiratory: inhaled spores)
gastrointestinal
blood stream
skin, hair, nails: contamination on skin surface or inoculated skin / trauma (subcutaneous)
urinary tract

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list some virulence factors of fungi

thermal dimorphism
toxin production
capsules + adhesion factors
hydrolytic enzymes
inflammatory stimulants

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the main antifungal defenses humans have is (1) and (2) and if those fail (3), (4), (5) are critical

1- barrier integrity
2- respiratory cilia integrity
3/4/5- cell-mediated immunity, phagocytosis, inflammation

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(T/F) long-term immunity can develop for all fungi

F- only for some fungi

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list the conditions that are ideal for opportunistic fungal infections

Weakened Immune System:

inheirited immunodeficiency disease
immunosuppressant drug therapy
radiation therapy
infection (HIV)
cancer, DM, advanced age, malnutrition

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list the 4 types of fungal diseases

1) hypersensitivity: allergic rxn to molds/spores
2) mycotoxicoses: poisoning via contaminated food with toxin producing fungi (lethal to poultry/livestock)
3) mycetismus: ingestion of pre-formed toxins (mushroom poisoning)
4) infections: mycoses

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fungal infection = …

mycoses

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list the 4 fungal classifications (morphological)

1) ascomycota
2) basidiomycota
3) zygomycota
4) mitosporic fungi

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Ascomycota reproduce (a-/sexually) within (2) to produce (3)

1- sexually
2- sacs called ascus
3- ascopspores

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Basidiomycota reproduce (a-/sexually) within (2) to produce (3)

1- sexually
2- sacs called basidium
3- basidiospores

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Zygomycota reproduce (a-/sexually) within (2) via formation of (3) and (4)

1- both
2- sacs called zygosporagium
3- gametes sexually
4- zygospores asexually

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Mitosporic Fungi (fungi imperfecti) reproduce (a-/sexually) and make up most of (2) fungi

1- no recognizable form of sexual reproduction | 2- pathogenic fungi

(1) is the largest fungal phylum in nature and includes (2), (3), and most all human fungal pathogens

1- ascomycetes (ascomycota) 2- Candida albicans 3- Pneumocytosis jirovecii

the most important Basidiomycete as a human pathogen is (1), although most are commonly (2)

1- Cryptococcus neoformans | 2- mushrooms

Malassezia furfur is a dimorphic fungi that causes (superficial / cutaneous / subcutaneous) mycoses called (2) with (3) as symptoms

1- superficial 2- Pityriasis (Tinea) versicolor 3- alters skin color Note- floresces under UV light

Hortaea werneckii causes (superficial / cutaneous / subcutaneous) mycoses called (2) with (3) as symptoms

1- superficial 2- Tinea Nigra 3- skin darkening

Piedra hortae causes (superficial / cutaneous / subcutaneous) mycoses called (2)

1- superficial infection of hair shaft | 2- black piedra (white piedra)

Trichophyton rubrum and T. mentagrophytes cause (superficial / cutaneous / subcutaneous) mycoses called (2) with (3) as symptoms

1- superficial infection of fingernails and toenails 2- Onychomycosis 3- discolored, brittle nails

(1) type of fungi are cause superficial mycoses and don't typically penetrate deeper as they acquire their nutrition because they are (2)

1- dermatophytes | 2- keratinolytic

Cutaneous mycoses can form (1) lesions and are spread via (2). Most causative agents are (3) introduced through (4). (5) is the biggest danger to these infections. With treatment (6) can result, but (7) usually occurs.

``` 1- macular, papular, pustular (herpetiform) lesions (itchy) 2- itching/scratching 3- soil organisms 4- to extremities after trauma 5- secondary bacterial infections 6- permanent patchy baldness 7- resolution w/o scarring ```

Sporothrix schenckii is a soil fungus that causes (superficial / cutaneous / subcutaneous) mycoses called (2) with (3) as symptoms

1- subcutaneous 2- Sporotrichosis 3- subacute / chronic granulomatous infection

(1) is a granulomatous inflammation that can extend from subcutaneous region to bone. (2) drain through sinuses producing (3) to help with this diseases identification.

1- mycetoma (eumycetoma) 2- pigmented nodules 3- colored grains

______ is a subcutaneous infection forming warty pigmented lesion which grows outward from site of introduction

Chromoblastomycosis

Candida albicans causes (1) described as (2)

(opportunistic infection) 1- candidiasis 2- superficial skin infection (cutaneous candidiasis), oral cavity (thrush), genitalia (vulvovaginal yeast infection), large intestine --> off-white pasty colony with yeasty odor

(1) is a very common airborne soil fungus that infects (2)- a major threat to (3) patients

1- Aspergillosis 2- lungs 3- AIDS, leukemia, transplant Pts (if invasive it can involve many organs)

Cryptococcus neoformans causes (1), is usually found in (2), and infects (3); commonly in (4) patients

``` (opportunistic infection) 1- Cryptococcosis 2- soil around pigeon roosts 3- lungs + others/brain 4- AIDS, cancer, DM Pts ```

(1) is caused by saprobic fungi found in soil/water/organic debris/food and is usually harmless but can invade (2) areas and have bad consequences particularly in (3) patients

(opportunistic infection) 1- zygomycosis/mucormycosis 2- nose, eyes, heart, brain 3- DM, malnutrition Pts

Pneumocystis jiroveci is a small unicellular fungus that causes (1) and is the most prominent opportunistic infection in (2) patients

1- pneumocystis pneumonia (PCP) 2- AIDS (fatal if not controlled with medication)

describe transport of fungal specimens

- hardy organism --> no special transport media required for culture submission - sterile containers used to prevent bacterial contamination

describe the common fungal culture medium

- solid media, SDA (Sabouraud Dextrose Agar): pH- 5.4 - Antibiotics: gentamicin, chloramphenicol (inhibit bacterial contamination) - Cycloheximide to inhibit saprophytic fungi - Other Agars: potato dextrose agar, brain heart infusion agar, Czapek Dox agar - Special Media used if particular fungus is suspected

septate fungi lesion are nearly always (1) aseptate fungi lesions are (2)

1- ascomycetes | 2- zygomycetes

pseudohyphae is a characteristic of ___ infections

Candida spp.

low-angle hyphal branching is characteristic of (1) right angle branching is characteristic of (2)

1- Aspergillus spp. | 2- zygomycetes

hyphae coloration is describe as (1) or (2)

1- dematiaceous (dark) | 2- hyaline (transparent)

enclosed spores = (1) open spores = (2)

1- sporangia | 2- conidiophores

what are Phialides

flask shaped cells from which conidia bud (a spore produced asexually by various fungi at the tip of a specialized hypha)

(1) are cells that become conidia as they break off from hypha, (2) are produced by budding from the ends of phialides or sides of hypha

1- arthrospores | 2- chlamydospores

big spores = (1) | small spores = (2)

1- macroconidia | 2- microconidia

define tuberculate

refers to 'knobby' appearance of a spore

describe typical microscopic features of yeast

oval/spherical, budding, or encapsulated

describe typical microscopic features of molds

hyphae, spores + spore forming structures

fungal samples may be prepared for stain by treatment with (1) where only the (2) feature survives and is visible in LM as (3)

1- 10% KOH 2- chitinous hyphae 3- hyaline shadows

Calcofluor white stain binds to (1) and is critical because it (2)

1- chitin | 2- fluoresces under UV light

____ is a key Gram+ fungi

Candida albicans

_____ is stain used to demonstrate hyphae, spores, and conidiophores

gomori methenamine silver staining

list ways to control fungal infections

- anti-fungal compounds that target specific pathways - surgical removal of damaged tissue (some cases) - prevention of infection via masks and protective clothing to reduce contact w/ spores Note- immunization is usually not effective

list two key pathways targeted by anti-fungals

- inhibition of ergosterol, β-glucan, chitin biosynthesis | - inhibition of DNA synthesis by depleting thymine pools

L37- Fungi Flashcards

(60 cards)