1. The Need for Fungi Ecologically important decomposers Break down complex organic molecules into simple molecules that can be used by other organisms

2. Classification, Structure, and Growth of Fungi Yeasts Molds Hypha Mycelium Mycology Mycosis Figure 8.2: A false-colored SEM of Cladosporium cladosporioides, one of the most common fungi isolated from air samples (x300) © Dr. Dennis Kunkel/Visuals Unlimited

3. Classification, Structure, and Growth of Fungi Structure of fungi –Nuclei –Many fungi form spores –No chlorophyll –Reproduce sexually and asexually –Cell walls Contain chitin Septa

4. Classification, Structure, and Growth of Fungi Nutrition in fungi –Heterotrophic Digestive enzymes secreted outside cell Brokendown products are then absorbed by cell –Some fungi can make enzymes that very few organisms make. Cellulase Ligninase –Glucose stored as glycogen What other organism store carbohydrates as glycogen? –Some fungi exist as saprobes –Some fungi exist as parasites

5. Classification, Structure, and Growth of Fungi Nutrition in fungi –Usually exist in acidic conditions –Therefore fungi can grow in familiar acidic foods Sour cream Yogurt Citrus fruit Most vegetables Bread Cheese –Favorable contamination Cheese (e.g., blue cheese and Penicillium requeforti)

6. Classification, Structure, and Growth of Fungi Reproduction in fungi –Asexual reproduction forms spores Hyphal fragmentation –Arthospores –Chlamydospores Mitosis – cell division where one parent cell results in two identical daughter cells that become spores –Spores »Most are formed on sporangium or conidiophore »Conidia are spores formed unprotected at the tip of a conidiophore. »Environmentally stable, like bacterial spores »Produces extremely large number of spores »All spores are genetically identical to parent cell

7. Classification, Structure, and Growth of Fungi Reproduction in fungi –Sexual reproduction Cell fusion and and spore formation Haploid parent cells (1n) Diploid progeny, called zygote (2n) Meiosis of zygote creates haploid spores (1n) Spores are environmentally resistant, like bacterial spores Spores germinate to form new haploid organism Results in fewer spores, but more genetic diversity when compared to asexual reproduction

8. Classification, Structure, and Growth of Fungi: Sexual Reproduction in Fungi Figure 8.5: Sexual Reproduction in Fungi Reproduced by permission of the National Research Council of Canada; O'Donnell, K.L., Ellis, J.J, Hesseltine, C.W. and Hooper, G.R. The Canadian Journal of Botany, 55(6): 662-675.

9. Divisions of Fungi Zygomycota Ascomycota Basidiomycota Deuteromycota

10. Divisions of Fungi Zygomycota –Called zygomycetes –Zygospores Thick-walled, environmentally resistant spores Develop from fusion of two sexually opposite cells –Rhizopus stolonifer: common black bread mold –Fermentation of rice into sake by one Rhizopus species –Cortisone production by different Rhizopus species

11. Divisions of Fungi Asomycota –30,000 species of ascomycetes (a.k.a., sac fungi) –Produce Asci – spore containing sacs –Most are filamentous –Some are yeasts –Septa allow mixing of adjacent cells’ cytoplasm –Ascospores – sexually produced Figure 8.6: Ascospores (A) and conidia (B) of the fungus Aspergillus quadrilineatus Reprinted with permission from the American Society for Microbiology (Polacheck I, Nagler A, Okon E, Darkos P, Plaskowitz J and Kwon-Chung, K.J.; J. Clin Microbiol, 1992 December; 30(12): 3290-3293.) Photo courtesy of Doctor K.J. Kwon-Chung

12. Divisions of Fungi Ascomycota –Various Penicillium species Antibiotics –Penicillin –Ampicillin –Amoxicillin –Methicillin Blue cheese –Various Aspergillus species Contaminate house dust Cause allergies, respiratory illness Aflatoxins Production of food products –Citric acid –Soy sauce –Vinegar –Beano –Claviceps purpurae -Infects rye -Ingestion results in ergot disease in humans -Potential headache cure, in low doses -Potential bioterrorism weapon