MycologyFungi, fungi, biological characteristics, significance
LIVING THINGS • 3 DOMAINS of Life: • BACTERIA • Prokaryotic Cells • ARCHAEA • Prokaryotic Cells • EUKARYA • Eukaryotic Cells
(Semi-Living Things) • Viruses • Non-cellular
Domain Eukarya • Kingdom Protista • Single-celled, Autotrophs or Heterotrophs, variable • Kingdom Plantae • Multicellular (mostly), Autotrophs, “Producers” • Kingdom Animalia • Multicellular (mostly), Heterotrophs, “Consumers” • Kingdom Fungi • Multicellular (mostly), Heterotrophs, “Decomposers”
Mycology • Mycology – from Greek “mykes” = mushroom, cap & “logos” = discourse, study. • Fungus (Fungi) – Latin, from the greek “Sphongous” = sponge-like, spongy.
Mycology • Mushrooms, Toadstools, Boletes, Yeasts, Molds, Mildews, Puffballs, Stinkhorns….
FUNGI • Huge group of very successful organisms – found in virtually all ecological niches on Earth. • Largest single organism on Earth is a fungus. (Armillaria ostoyae) • ~100,000 species* so far described, but there are likely many more (up to 2 million). • Inadequate sampling • *Species? Individual? • Traditionally, fungi (particularly mushrooms) have been studied by botanists, however, they are “achlorophyllous”.
Fungi vs fungi • Fungi are a monophyletic (closely related) group of organisms all sharing a common ancestry and evolutionary history, and sharing many common characteristics. “TRUE Fungi” • fungi are organisms that share many characteristics with Fungi (and so superficially resemble them), but DO NOT share a common ancestry and evolutionary history. “fungus-like organisms”
FUNG-ISMS • Myco… • …mycetes • …mycota • …mycotina • Pathogenic/pathogen vs free-living • Dimorphism (Anamorph, Teliomorph --- Holomorph)
Characteristics of Fungi • Heterotrophic (Saprobic or Parasitic) • Extracellular digestion • Enzymes (hydrolytic, proteases, etc.) break down macromolecules dimers & monomers. • These digestion products are then absorbed. • An adaptive morphology allows for sufficient surrounding of food and sufficient energy intake to counteract the energy spent in digestive enzyme production…
Characteristics of Fungi • Most are filamentous (adaptive morphology for increased surface area). • Vegetative body called a Mycelium (pl. Mycelia). • A Mycelium is composed of numerous Hyphae (sing. Hypha), each 1 cell wide.
Characteristics of Fungi • Some are small “uni-cells” • Yeasts • Chytridiomycota Yeasts Filamentous Stage Chytrids
Characteristics of Fungi Cell Wall
Characteristics of Fungi • Cell Wall is composed of Chitin. • Complex, N-containing Polysaccharide (a carbohydrate polymer). • Helps maintain osmotic pressure in the cells.
Characteristics of Fungi • The vegetative (somatic) body of a fungus is the Mycelium: the absorptive, “adult”, feeding stage.
Hyphae • Septa (sing. Septum) are partitions between hyphal cells. • Aseptate taxa are coenocytic (multi-nucleate). • Septate taxa typically have a Septal Pore.
Characteristics of Fungi • Rhizomorphs – root like masses of hyphae.
Characteristics of Fungi • A fraction of the vegetative mycelium is devoted to reproduction. • Specialized hyphae bearing Spores. • Spores are tiny propagules.
Spores • Dispersal • Protection • Survival • Reproduction. • Asexually-produced spores are disseminative. • Sexually-produced spores are reproductive AND disseminative.
Asexually-Produced Spores • Spores are borne on hyphal tips called Conidia (sing. Conidium) or in Sporangia (sing. Sporangium).
Asexually-Produced Spores • Produced by Mitosis & Cell Division. • Clones (genetically-identical progeny) are produced.
Sexually-Produced Spores • Spores are borne on unique and specialized structures, depending on the type of fungus. • Produced by Meiosis & Cell Division. • Genetically-unique progeny are produced. • Sexual Reproduction = combined genetic contributions of two parents. • Life cycles.
Life Cycles HAPLOID STAGE (1N) MEIOSIS FERTILIZATION DIPLOID STAGE (2N)
Gametic Life Cycle 1N 2N
Gametic Life Cycle • Meiosis produces gametes (sperm or egg). 1N 2N
Zygotic Life Cycle • Meiosis produces spores (mini-zygotes). 1N (Gametes here produced by Mitosis) (Spores) 2N
Classification of Fungi • Fungi comprise a monophyletic group broken into 4 lineages (therefore also 4 Phyla): • Phylum: Chytridiomycota • Phylum: Zygomycota • Phylum: Ascomycota • Phylum: Basidiomycota • “Phylum”: Deuteromycota is an artificial group representing fungi that do not or have yet to exhibit a sexual stage (meiosis & syngamy).
Phylogeny of Fungi Morphological Character state changes
Chytridiomycota • Swimming Zoospores.
Zygomycota The “Bread Molds”
Zygomycota • Sporangium (sporangia) • Asexual spores
Zygomycota • Zygospore • Sexual “spore” (Suspensors)
“Glomeromycetes” • Mycorrhizal Fungi • (Endomycorrhizal) • VAM fungi: Vesicular-Arbuscular Mycorrhizae
Ascomycota The Sac Fungi Morchella esculenta
Ascomycota • Ascus (sac) is where the sexual spores (Ascospores) are borne. • 8 Ascospores are typical in each ascus.
Basidiomycota The ‘Club’ Fungi
Basidiomycota • Sexual Basidiospores borne on a Basidium. • 4 spores per Basidium. Basidiospores Basidium
Studying FUNGI • Both Macroscopic and Microscopic organisms. • Cultures • 1-member, 2-member • Growth Media (sing. Medium) • Agar, Broth • Petri Plates or Culture Tubes.
Significance & Importance • Sources of important chemicals • Medicines. • Antibiotics like Penicillin, Cephalosporin. • Eastern Medicine, herbal remedies, anti-tumor, etc. • Metabolites • Plant growth hormones, steroids. • Mycotoxins, biological control agents. • Transformative enzymes. • Alcohol fermentation with CO2 production by Saccharomyces cerevisiae (yeast). • Cheese ripening, sausage production, miso
Significance & Importance • Food sources. • Mushrooms • Shiitake, Oyster, Porcini, Portobello, Morel, Truffle… • Wild Mushrooms….Poisonings. • Cheeses, Miso, Beer, Wine, Bread. • Cultivation…by humans and other animals. • Spiritual ceremony & shamanism. • Natives of Mexico & Central America – hallucinogenic religious rites involving Psilocybe cubensis. (more recently studied by Wasson, McKenna, & others). • Mushroom effigies associated with many primitive (& modern) cultures.
Significance & Importance • Ecosystem Contributions • Decomposers of cellulose, lignin (wood). (often found in human-manufactured items) • Control of nutrient cycling. • Soil retention. • Mycorrhizal associations with plants. • Plant pathogens • Potato blight (Oomycete) • Chestnut blight (Cryphonectria parasitica) • Dutch elm disease (Ophiostomasp.) • Ergot of Rye (Claviceps purpurea)
Significance & Importance • Animal Pathogens • Insects (Oomycetes, Laboulbeniales, Septobasidium). • Humans (‘mycoses’) • Ringworm, histoplasmosis, yeast infections. • Scientific “lab rats” • Especially Genetics • Schizophyllum commune, Neurospora