Lecture 12 Fungi PDF

7/7/24 Lecture 12 Fungi Fu...

7/7/24 Lecture 12 Fungi Fungi - General Features We will start with Protists, so bring outline from Domain: Eukarya last time Kingdom: Fungi Size: From single celled yeast to 3-mile-wide Reading: Chapter 24 All Sections honey mushroom Other features: The term fungi evokes delectable dishes made Lack chlorophyll with wild or cultivated mushrooms; foods made Plasma membrane with the help of yeasts, such as beer, wine and bread; athletes foot and other infections, or Cell walls of chintin (polymer of N-acetylglucosamine) moldy food forgotten in the refrigerator. Nutrition: M. Schaechter, J.L. Ingraham, and F.C. - Saprophytes - nutrients from dead organic matter Neidhardt. 2005. Microbe. ASM Press. - Absorptive - secrete enzymes, absorb nutrients 1 2 Fungi Terms Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Aspergillus Fungi: The Great Decomposers Mycology - study of fungi Mycoses - disease caused by fungi able to break down many complex organic compounds including cellulose Mycotoxicosis - poisoning by fungal toxin Aflatoxins toxic compound - without fungi, dead plants and trees would - – Carcinogens substance cancer - > -> accumulate to great depths – Intercalate between DNA bases, cause Claviceps mutations without fungal activity and resulting CO2 Ergot alkaloids production - plant, and ultimately human life – LSD structure Lysergic acid diethylamide would cease - – Cause delusions and convulsions – Used to treat migraines and induce labor 3 4 Fungi Distribution Mostly terrestrial, some aquatic Can be part of human microflora Can be pathogens Can form associations Lichens = fungi and Cyanobacteria Mycorrhizal fungi and plants Truffles 80% of all land plants ↑ Fungus provides soil nutrient 5 6 Plant provides fungus carbohydrate ~ 1  7/7/24 Yeasts Molds Unicellular fungi Multicellular fungi Hyphae – filaments of a mold Saccharomyces cerevisiae Mycelium – mass of hyphae – bread, beer, wine Candida albicans Thrust – microflora of mouth, -Candida Aseptate- no cross walls vagina and intestinal tract infection of ⑯ Candida auris mouth Some fungi change from urgent threat Yeast to Mold form Drug resistant YM shift 7 8 Septate - cross wall 07:26 Fungi: Sexual Reproduction Fungi: Asexual Reproduction Often under stress or limiting nutrients Offspring genetically identical to parent Offspring genetically intermediate 3 mechanisms Binary fission Haploid cells opposite mating types (+,-) fuse Budding Pheromones signal between types Spore production chemical signal Ex: conidiospores, sporangiospores 9 10 Fungi Sexual Reproduction Fungal Subclasses Fusion creates single hypha with 2 distinct nuclei - dikaryon 18S rRNA analysis groups fungi into at least 7 Nuclei can fuse forming diploid zygote groups or subclasses Meiosis forms haploid spores Ex: Zygospores, Ascospores Lets consider features and members of four: Videotaped sequence of successful hyphal fusion (t = min) – Chytridiomycetes – Zygomycetes (Mucormycota) – Ascomycota 11 – Basidiomycota 12 Courtesy: P. McCabe, M.P. Gallagher, J.W. Deacon Univ. of Edinburgh 2  7/7/24 Chytridiomycetes Zygomycetes - (mucormycotal Simplist fungi Sexual zygospores, asexual aquatic sporangiospores Ex: motile flagellated zoospores. - rhizopus - bread mold Tempeh - rhizomes uses: fermented soybeans chytridiomycusis - massive frog meat tenderizer deaths birth control agents plant pathogen - Rice Seedling Blight 13 14 Does Rhizopus toxin cause Rice Seedling Blight? Page 524 Yes toxin produced by a-proteobacterium , within & Bulkholderia up growth Mold fungus Ascomycota Ascomycota Sac fungi – ascus Histoplasma capsulatum – sexual ascospores Histoplasmosis Dimorphic – asexual conidiospores Mold spores, called conidia, inhaled Yeast Germinate into yeast in lung Yeast grows in human macrophages Aspergillus Penicillium Saccharomyces Pseudogymnoascus White Nose Syndromd in bats Psychrophile Infects skin of hibernating bats Large scale killing 15 Fruiting Bodies (stoma) in Ascomycota Basidiomycota caterpillar heads Cordycepts Club fungi Insect pathogen Basidium - bears sexual basidiospores story page 518 - look terms for exam 3 Examples: Sexual reproduction involves meiosis of a Mushrooms diploid nucleus in an ascus, giving rise to Cryptococcus neoformans haploid ascospores; most also undergo asexual reproduction with the formation of conidiospores with specialized aerial hyphae called conidiophores. Many produce asci 18 within complex fruiting bodies called ascocarps. Includes saprophytic, parasitic forms; many form mutualisms with phototrophic microbes to form lichens. 3  7/7/24 Anatomy of a Mushroom Basidiomycota Mushrooms - Cap > - Genus: Agaricus- edible mushrooms Genus: Amanita - ↓ includes death angel Gills with Amanitin - peptide toxin basidia - Stalk + Target RNA polymerase ccup-like -volva Mycelium- 19 20 Basidiomycota Capsule Cryptococcus neoformans Calvatia gigantea Giant Puffbal - fruiting bodies – Pathogen in AIDS and other with internal basidiospores immunocompromised What two virulence factors are shown – Basidiospores inhaled in these pictures? – Source: Pigeon droppings Melanin Pigment – Infects lung, central nervous system – Can cross blood-brain barrier 21 4