Fungi Flashcards
What are characteristics of fungi ?
- Eukaryotes
- Heterotrophs
- cell wall made of chitin
- multinucleated cells
- lacking chloroplasts and chlorophyll
- devoid of leaves, stems or roots
What are some characteristics of yeasts ?
single celled fundal forms
What are some characteristics of molds ?
multiple cells forming a filamentous mycelium
What are some characteristics of spores ?
- fungi reproduce by spores (sexually or asexually)
-morphology, arrangement, and mode of derivation of spores serve as criteria for genus and species identification
What are the habitats of fungi ?
- found in nearly every habitat on Earth where organic materials exist
What are the 4 ways fungi can harm humans ?
- allergic reaction
- reaction to toxin
- fungi that destroy the human food supply
- colonization of the human body by fungi (mycoses)
What are some examples of allergic reactions caused by fungi ?
mold allergy causes your immune system to overreact when you breathe in the spores
- exposure causes person to become sensitized
- can cause coughing, itchy eyes, etc
- can be linked to asthma and cause restricted breathing and other airway symptoms
How does a reaction to a toxin cause harm to humans ?
- hallucinogenic properties of some mushrooms
- poisonous effects of ergot fungus (rye smut)
- carcinogenic toxins of Aspergillus (aflatoxins)
What is an example of a reaction to a toxin caused by fungi ?
ergot fungi causes Ergotism
- causes severe vasoconstriction leading to gangrene due to loss of blood circulation
- ergot alkaloids may cause hallucinations and attendant irrational behavior, convulsions, and even death
- Ergometrine (from Ergot) is also used to induce uterine contractions and to control bleeding after childbirth
What is an example of a way that fungi destroy the human food supply ?
- Wheat Rust: Puccinia graminis
- Potato Blight: phytophthora infestans
What are the 3 ways the fungi colonize the human body through mycoses ?
- superficial
- intermediate
- systemic
What are some infections caused by superficial mycoses ?
- candidiasis (thrush, vaginal (yeast infection) )
- dermatophytes (athletes food, jock itch, nails)
- sporotrichosis (gardener’s hazard)
- blastomycosis (skin)
What is athlete’s foot (tinea pedis) ?
common skin infection of the webs of the toes and soles of the feet
- may spread to the palms, groin
- S&S: itching, scaling, and redness
- in severe cases it can cause skin blistering
What is candidiasis ?
develops in the mouth or throat (thrush), or oropharyngeal candidiasis. or in the vagina (yeast infection)
What are some infections caused by intermediate mycoses ?
- Aspergillus (lungs, gut-ingested spores, fungal ball)
- Candidiasis (children and immunocompromised)
- Cryptococcus (pulmonary, cerebral)
- All dimorphic (any organ)
- Mucormycosis: rhino cerebral (nasal passages and brain), pulmonary, GI, fungal ball
What is Aspergillosis ?
wide array of diseases caused by infection by fungi of the genus Aspergillus
- majority of cases happen in pt’s with underlying illnesses like TB, COPD
- pt’s that are immunocompromised are at higher risk for disseminated disease
What is a fungus ball ?
another name for Aspergillosis
What are the S&S of a fungal ball ?
may cause no symptoms
- may be discovered only with a chest X-ray
- or can cough up blood, chest pain, occasionally severe even fatal bleeding
What happens is Aspergillosis isn’t treated ?
can disseminate through the blood stream to cause widespread organ damage
What are some infections caused by systemic mycoses ?
- Mucormycosis (necrotizing, rapid, fulminating)
- Aspergillosis
- Candidiasis
- Cryptococcus
- All dimorphics
What are dimorphic ?
mycotic organisms that possess different morphological forms under different temp conditions
- histoplasmosis
- blastomycosis
- coccidiomycosis
What is Mucormycosis ?
serious but rare fungal infection caused by a group of molds called mucoromycetes
- affects people that are immunocompromised
- these molds live throughout the environment
- affects the sinuses or lungs after inhalation of spores from air or skin
What is Cryptococcus Neoformans ?
fungus that lives in the environment throughout the world
- infection occurs after breathing in microscopic fungus
- extremely rare in otherwise healthy adults
- most cases occur in immunocompromised pt’s (especially advanced AIDS/HIV)
What are some positive effects of fungi ?
for genetic and biochemical studies
- yeasts (produce human insulin, growth hormone, somatostatin, vaccine against viral hepatitis)
- fungi as food (mushrooms and yeast in breads and alcohol)
- in symbiosis (lichens)
What are 3 ways to identity fungal infections ?
- direct observation
- culture
- preliminary isolate observations
