Introduction to Fungi 1 Flashcards
<p>What can fungi infect?</p>
<p>Plants</p>
<p>Insects</p>
<p>Amphibians</p>
<p>Mammals</p>
<p>What is fungas?</p>
<p>A chemo-organotrophic eukaryoate that lacks chlorophyll and forms spores</p>
<p>What does the cell wall of fungus contain?</p>
<p>Polysaccharides</p>
<p>Often chitin or glucan which absorbs nutrients</p>
<p>What is the classification based on?</p>
<p>Morphology (shape)</p>
<p>What do we informally refer to fungi as?</p>
<p>Moulds, yeasts or mushrooms</p>
<p>What are the 3 groups of fungus?</p>
<p>Basidomycetes</p>
<p>Ascomycetes</p>
<p>Zygomycetes</p>
<p>What is the sexual and asexual spore of basidomycetes?</p>
<p>Sexual spore is basidospore</p>
<p>Asexual spores is conidum</p>
<p>What is the sexual and asexual spore of ascomycetes?</p>
<p>Sexual spore is ascospore</p>
<p>Asexual spore is conidium</p>
<p>What is the sexual and asexual spore of zygomycetes?</p>
<p>Sexual spore is zygospore</p>
<p>Asexual spore is sporangiospore</p>
<p>What are examples of basidomycetes?</p>
<p>Mushrooms</p>
<p>What are examples of ascompycetes?</p>
<p>Neurospora</p>
<p>Saccharomyces</p>
<p>What are examples of zygomycetes?</p>
<p>Bread moulds</p>
<p>What are examples of basidiomycete pathogens?</p>
<p>Mucor</p>
<p>Rhizopus</p>
<p>What are examples of ascompycete pathogens?</p>
<p>Cryptococcus</p>
<p>Malassezia</p>
<p>What are examples of zygomycete pathogens?</p>
<p>Candida</p>
<p>Histoplasma</p>
<p>What is in the structure of a basidiomycete?</p>
<p>Basidospores</p>
<p>Sterigmata</p>
<p>Septum</p>
<p>Hypha</p>
<p>What is contained in ascomycetes and where?</p>
<p>Ascospores contained within a sac</p>
<p>What is the structure of a zygomycete?</p>
<p>Rough walled zygote, contains one or more zygospore</p>
<p>What are yeasts?</p>
<p>Fungi that favours a unicellular habit</p>
<p>What are examples of non-fetal diseases caused by fungi?</p>
<p>Athletes foot (caused by epidermophyton)</p>
<p>Thrush (caused by candida spp)</p>
<p>Pityriasis versicolor (caused by malassezia spp)</p>
<p>What is athelete's foot caused by?</p>
<p>Epidermorphyton</p>
<p>What is thrush caused by?</p>
<p>Candida spp</p>
<p>What is pityriasis versicolor caused by?</p>
<p>Malassezia spp</p>
<p>What are dermatophyte infections?</p>
<p>Fungi have enzymes that degrade and utalise keratin as a nutrient source which is caused by epidermorphyton</p>
What is degrading and utilising keratin as a nutrient known as?
Dermatophytosis
What are 3 fungi that cause skin disease?
Epidermophyton floccosum
Microsporum canis
Trichophyton mentagrophytes
What is pityriasis versicolour?
A yeast infection that also forms hyphae in infected skin
What are examples of fungi that can cause fatal disease?
Candida spp
Asperigillus spp
What does candida spp do?
Infects deep organs of patients with immune dysfunction
What does asperigllus spp do?
Infects deep organs of patients undergoing chemotherapy or stem cell transplantation
What are host factors that contribute to pathogenicity of fungal infections?
Favourable micro environments (warm, moist areas)
Broad antimicrobial agents reduce competition
Immunosuppresion creates window of opportunity for fungal infection
What can immunosuppresion of hosts be?
Iatrogenic (illness caused by treatment)
Disease processes
What are iatrogenic causes of immunosuppresion?
Steroids
Chemotherapy
Organ transplantation
What is iatrogenic?
Illness caused by treatment
What are disease processes that cause immunosuppresion?
AIDS
Leukaemia
What kinds of infections do candida infections cause?
Oral
Vaginal
Skin
Nail
Urinary tract
What kinds of fungi are the candida spp?
Yeasts
What is dissemination?
Spreading
What is the process of dissemination of candida spp?
1) Part of normal commensal gut flora
2) Antibacterial drugs wipe out competition
3) GI tract wall damaged
4) Spreads through blood
What is hyphae?
Long branching structure of a fungi
What is aspergillosis caused by?
Aspergillus spp
What diseases does aspergillosis lead to?
Asthma
Aspergilloma
What is the process of aspergillosis infecting?
1) Inhaled
2) Forms hyphae in lung tissue
3) Invades blood vessels
What is cryptoccososis caused by?
Cryptococcus spp
What are the cryptococcus spp?
Yeasts with a capsule
What diseases does cryptoccososis lead to?
Pulmanory cryptococcosis
Meningitis
Disseminated infection in severely compromised hosts
Why is too much and too little immunity to fungi a bad thing?
Too much leads to a hypersensitive response and too little leads to infection
How is fungi diagnosed?
Histopathology (under the microscope)
High resolution CT scan
What are the 3 main classes of anti-fungal drugs?
Triazoles (target steroids)
Echinocardins (target walls)
Polyenes (target membranes)
What do triazoles target?
Steroids
What do echinocandins target?
Cell wall
What do polyenes target?
Membrane
What are common problems with anti-fungal drugs?
Targets are not broad enough
High toxicity
How do triazoles work?
Inhibit production of sterols by targeting enzymes (Erg11)
What is an issue with triazoles?
Resistance has been developed my mutation of Erg11 which pumps the drug out
How do polyenes work?
Form pores in the cell wall that cahnges the internal environment and kill the fungi
How do echinocandins work?
Inhibit glucose synthesis to prevent glucans being made, which weakens the cell wall and they cannot grow
What is a problem with echinocandins?
Resistance is acquired by mutations of enzymes
