Fungi and medicine L20 Flashcards
What are mycoses?
Fungal infections in humans.
Who is most vulnerable to serious fungal infections?
Immunocompromised individuals (e.g. HIV, transplant patients, chemotherapy).
what are dermatophyte and what do they cause?
these are fungi that infect keratinised tissues
cause ringworn, athletes foot, nail infections
how do dermatophytes infect?
use keratinases to digest keratin in skin, hair and nails
what is Candida albicans?
a commensal yeast that can become pathogenic, causing trust and systemic infections
why is Candida albicans dangerous in immunocompromised people?
because it can cause system candidiasis which is life threatening
what is unique about c.albicans morphology
it is dimorphic so it switches between yeast and hyphal forms
Name two fungi that cause lung infections in immunodeficient patients.
Aspergillus fumigatus and Cryptococcus neoformans.
What helps Cryptococcus neoformans survive in hosts?
Thick capsule, growth at 37°C, melanin for oxidative protection.
What do azoles (e.g. fluconazole) target?
Ergosterol synthesis in the fungal membrane.
What do polyenes (e.g. amphotericin B) do?
Bind ergosterol, create pores in membranes – toxic to fungi (and humans!).
what is ergosterol ?
a molecular found in fungal cell membranes, similar to cholesterol in animal cells
What do echinocandins (e.g. caspofungin) inhibit?
β(1,3)-glucan synthesis – weakens fungal cell walls.
What does flucytosine do?
Inhibits DNA and protein synthesis – used with amphotericin B.
What is aflatoxin B1 and why is it dangerous?
A carcinogenic mycotoxin from Aspergillus flavus, causes liver cancer.
What is cordycepin?
A bioactive compound from Cordyceps fungi, studied for health benefits.
What is ergotamine and where is it from?
An alkaloid from Claviceps purpurea (ergot), used to treat migraines and childbirth bleeding.
What is LSD derived from?
: Lysergic acid, originally isolated from Claviceps purpurea.
What causes St Anthony’s Fire?
Poisoning by ergot alkaloids from contaminated grains.
What causes toxicity when alcohol is consumed with ink cap mushrooms?
Coprine – inhibits aldehyde dehydrogenase.
What psychoactive compounds are found in Psilocybe species?
A: Psilocin and psilocybin
What mushrooms contain amatoxins, and what do they do?
Amanita phalloides – inhibit RNA polymerase II, causing liver failure.
What is muscarine, and what are its effects?
A toxin from Amanita and Clitocybe species – causes parasympathetic overstimulation (sweating, blurred vision).
What is orellanin, and what does it damage?
: A toxin from Cortinarius spp. that causes kidney failure.
