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Fungal Biodiversity

Fungal Biodiversity. Structure eukaryotic - individual cells are typically larger and more complex than bacterial cells

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Fungal Biodiversity

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  1. Fungal Biodiversity

  2. Structure eukaryotic- individual cells are typically larger and more complex than bacterial cells Dimorphic - unicellular (yeasts) or multicellular (molds ... mycelium that is a mesh of elongated filamentous hyphae that are frequently branched, with perforated septa between cells to ensure unimpeded movement of nutrients from one region of the mycelium to another) ... some fungi are dimorphic (change back and forth from yeast to mold) Chitin in cell walls of most, but some contain cellulose instead; protect the cytoplasm from osmotic pressure changes and provides cell shape Membranes- glycerol-based phospholipids with ester linkages which form typical bilayer membranes Ribosomes-80S RNA/protein particles which are required for protein synthesis Characteristics of Fungi

  3. Genetics • chromosome - multiple, non-identical DNA molecules complexed with histones; the DNA contains the "blueprint" for all cell structure and activity in regions called genes • introns and exons are present in fungi, as they are in the typical eukaryote • gene exchange - recombination during meiosis generates diversity

  4. Reproduction - generally via modified hyphae that form reproductive spores • sexual - fusion of haploid nuclei leading to formation of spores • asexual • binary fission • budding - unequal binary fission • fragmentation of hyphal elements • arthrospores formed directly from hyphal fragmentation • chlaymdospores formed from directly hyphal fragmentation, but surrounded by a thick wall • Spores - thick walls help them withstand dry, cold, low-nutrient conditions

  5. Physiology • aerobic (some facultatively anaerobic, but none are anaerobic) organotrophs • absorptive nutrient uptake- these cells secrete digestive enzymes to break down macromolecules to their subunits, then internalize the subunits to derive energy and structural building blocks • most are mesophilic (20-35C optima); some are psychrophilic, some are mildly thermophilic • pH optimum near 5.5, but some grow at extremes of the pH range 2-9 • Habitat - generally prefer dark, moist habitats containing organic material • terrestrial or aquatic (some live in freshwater, others in marine, habitats) • symbiotes with plants (mycorrhizae) or algae or cyanobacteria (lichens) • Importance • most saprophytic (decomposers); some are pathogenic for plants or animals • some are symbiotic, especially those that are the fungal component of lichens • important commercially in food production and spoilage, as well as pharmaceutical and industrual chemical production

  6. Groups of Fungi (~100,000 species)

  7. Chytridiomycota - Chytridiomycetes or Chytrids morphology - globe-shaped cells with rhizoids • Reproduction • habitat/importance • saprophytic decomposers which grow in on decaying plants or animals, mainly in freshwater habitats (including mud) • parasitic - some infect living plants, animals and other fungi

  8. Zygomycota- Zygomycetes, zygosporangium-forming fungi (~600 species) Morphology - mycelial Habitat/importance generally saprophytic decomposers in soil, important in plant decay Rhizopusstolonifer (common bread mold) is used commercially to produce tempeh (from tofu), pharmaceuticals including anaesthetics, contraceptives, industrial alcohols, meat tenderizer, yellow dye for margarine

  9. Ascomycota-Ascomycetes, sac fungi (~35,000 species) Morphology - dimorphic (yeast or mycelium with septatehyphae) Habitat/importance - generally saprophytic decomposers in soil, but some are used for food and some are parasitic • helpful - Morchellaesculenta (morels) and Tuber brumale (truffles) are edible; Saccharomyces (cerevisiae, carlsbergensis, ellipsoideus) used to make bread, beer, wine; Neurosporacrassa genetics research tool (spoilage-inducing bread mold) • damaging (parasites, etc.) - Clavicepspurpurea causes ergot of rye; 

  10. Basidiomycota -Basidiomycetes, club fungi, aka mushrooms (~30,000 species) • morphology - dimorphic (yeast or mycelium with septatehyphae and fruiting bodies we recognize as mushrooms, shelf fungi, puffballs, etc.) • reproduction • sexual spores are basidiospores - formed by the basidium (club-shaped structure at tip of hyphae; may be inside a fruiting body called a basidiocarp) • asexual reproduction - budding, fragmentation of the mycelium, and by production of conidiospores, arthrospores, or oidia (Coprinuslagopus) • habitat/importance - generally saprophytic decomposers in soil, but some are used for food and some are parasitic • helpful - Agaricuscampestrisbisporus is an edible mushroom • damaging (parasites, etc.) - Amanita phalloides is poisonous (produces phalloidin and alpha-amanitin); Cryptococcus neoformans, human pathogen; Pucciniagraminis causes black stem wheat rust; Ustilagomaydis - causes corn smut

  11. Thanks

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