Medical Mycology: Fungi Properties, Benefits & Harmful Ef...

--- MEDICAL MYCOLOGY — EXAM NOTES (MBMM3334) --- SECTION 1: INTRODUCTION & GENERAL PROPERTIES Mycology = study of fungi ( mykes = mushroom in Greek). Fungi inhabit almost every environmental niche. Historical milestones: 1835 — Bassi: first documented animal fungal infection 1910 — Sabouraud published Les Teignes → Father of Medical Mycology --- Beneficial Effects- Decomposition → nutrient/carbon recycling Fermentation → alcohols, fats, organic acids (citric, oxalic, gluconic) Antibiotics → Penicillin from Penicillium spp. Model organisms → Neurospora crassa (genetics); S. cerevisiae (recombinant DNA, Hep B vaccine) Food → mushrooms, vitamins, cofactors from yeasts Cheese flavouring → Penicillium spp. Ergot alkaloids ( Claviceps purpurea ) → uterine contractions, bleeding control, migraine treatment Biocontrol → Leptolegnia caudata & Aphanomyces laevis trap mosquito larvae (malaria control) Harmful Effects- Destroy lumber, paper, cloth Cause human/animal diseases and allergies Produce mycotoxins and poisonous mushrooms Cause crop diseases (e.g. potato blight) Spoil stored agricultural produce --- General Properties- Eukaryotic — membrane-bound organelles Rigid cell wall made of chitin (not cellulose like plants) No chlorophyll — cannot photosynthesize Chemoheterotrophs — need organic compounds for carbon AND energy Ergosterols in membranes — regulate permeability/fluidity → KEY antifungal drug target 80S ribosomes (eukaryotic; bacteria have 70S) Nutrients obtained as saprophytes (dead matter) or parasites (living matter) Need water and oxygen → no obligate anaerobes Reproduce by spores (sexually and/or asexually) Grow by budding (reproductive) or hyphal tip elongation (non-reproductive) Store food as lipids and glycogen Growth and Nutrition- Optimal pH: ~5.0 (acidic) Most grow at 25°C ; pathogens grow at 37°C Grow in high sugar concentrations (inhibits competing organisms) Use glucose and maltose for energy; store glycogen Mostly aerobic; fermentation yeasts can grow in low oxygen ---