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Fungi: Molds and Yeasts

Fungi: Molds and Yeasts. Types of Fungi. Yeast: unicellular Molds: multicellular. Molds. The cells are filamentous structures called hyphae (singular = hypha). Hyphae are little tubes.

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Fungi: Molds and Yeasts

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  1. Fungi: Molds and Yeasts

  2. Types of Fungi • Yeast: unicellular • Molds: multicellular

  3. Molds • The cells are filamentous structures called hyphae (singular = hypha). Hyphae are little tubes. • Some have individual cells separated by crosswalls called septum. These are known as septate hyphae. Those without septums are called aseptate or non-septate hyphae. You can only see this under a microscope. • The cell walls are made of polysaccharide (chitin or cellulose). • When a mass of hyphae are visible, it is called mycelium.

  4. Two kinds of hyphae in mycelium • 1. Vegetative hyphae: these procure nutrients by secreting enzymes into the substrate (food source) which catabolize (break down) the nutrients, which are then sucked up through the hyphae. The vegetative hyphae also serve as an anchor on which they are growing. These hyphae are heterotrophs because they get energy by breaking down organic matter. Molds are the decomposers of the food chain, and that is also their ecological niche. Ecology is the study of the interrelationships of living things with each other and their environment. An environment contains both living and non-living things. These relationships should be balanced. Every living thing has a place. We can disturb the balance with our waste products. Fungi return organic matter to the earth by breaking it down with their vegetative hyphae.

  5. Two kinds of hyphae in mycelium • 2. Aerial hyphae: living things also need to reproduce; that is the role of the aerial hyphae. They reproduce by spore production. How are these spores different than bacterial spores? One hyphae produces thousands of spores, for reproduction. One bacterium produces one spore, for survival. Very few soil bacteria also make reproductive spores.

  6. YEASTS • The term “yeast” refers to just the morphology (single cell fungus, reproduces by asexual budding, may or may not have sexual cycle); “yeast” is not the taxonomy. Yeasts look like bacteria; they are smooth with no mycelium. They divide asexually by either binary fission (symmetrical) like bacteria, or by budding (asymmetrical). One yeast that produces alcohol is Saccharomyces, and is used in fermentation of beer and other alcoholic beverages.

  7. Pathogenic Fungi and Their Diseases • OPPORTUNISTIC MYCOSES • Candida albicans (Candidiasis: yeast infection in women and thrush in children) • Aspergillus (Aspergillosis) • Cryptococcus neoformins (Cryptococcus) • Pneumocystis (Pneumocystis pneumonia; most common pneumonia) • CUTANEOUS MYCOSES (most common; fungus of the hair, skin, nails) • Microsporum (scalp infections and ringworm) • Epidermophyton (ringworm, jock itch, athlete’s foot) • Trichophytum (ringworm, jock itch, athlete’s foot) • SYSTEMIC MYCOSES (most serious; most often occurs in lungs) • Coccidiodes immitis (Valley Fever) • Histoplasma capsulatum (Histoplasmosis) • Blastomyces dermatitidis (Blastomycosis)

  8. Opportunistic pathogens • Candida • Aspergillus • Cryptococcus • Pneumocystis pneumonii • Dermatophytes True Pathogens • Histoplasma (true pathogen) • Blastomyces (true pathogen)

  9. Fungi Classification • Kingdom Mycetae (Fungi) • Division Amastigomycotina • A. Subdivision Zygomycota • B. Subdivision Ascomycotina • C. Subdivision Basidiomycota • D. Subdivision Deuteromycota

  10. Fungi Classification • Kingdom Mycetae (Fungi) • Division Amastigomycotina • A. Subdivision Zygomycota • 1. Rhizopusstolonifer (zygote) • 2. Rhizopusstolonifer (sporangiospore)

  11. Fungi Classification • Kingdom Mycetae (Fungi) • Division Amastigomycotina • A. Subdivision Zygomycota • 1. Rhizopusstolonifer (black bread mold) • Zygote (sexual spore) • Hyphae

  12. Fungi Classification • Kingdom Mycetae (Fungi) • Division Amastigomycotina • A. Subdivision Zygomycota • 2.Rhizopusstolonifer (black bread mold) • Sporangiospores (asexual spores) • Hyphae • Sporangium • Sporangiophore • Rhizoids • Columnella

  13. Hyphae Columnella Hyphae

  14. Rhizopus Zygospore

  15. A Young Rhizopus Zygospore

  16. Mature Rhizopus Zygospore

  17. Rhizopus Zygospores

  18. Fungi Classification • Kingdom Mycetae (Fungi) • Division Amastigomycotina • A. Subdivision Zygomycota • B. Subdivision Ascomycotina • C. Subdivision Basidiomycota • D. Subdivision Deuteromycota

  19. Fungi Classification • Kingdom Mycetae (Fungi) • Division Amastigomycotina • B. Subdivision Ascomycotina • 3. Penicilliumnotatum- ascospores (sexual spore) • 4. Penicilliumnotatum- phialospore (asexual spore) • 5. Morchella spp- ascospores (sexual spore) • 6. Aspergillus niger - phialospore (asexual spore) • 7. Saccaromycescerevisiae -yeast- (asexual spore)

  20. Fungi Classification • Kingdom Mycetae (Fungi) • Division Amastigomycotina • B. Subdivision Ascomycotina • 3. Penicilliumnotatum- ascospores (sexual spore) • Cleistothecium (completely closed fruit body) • Hyphae • Ascus (sexual spore-bearing cell) • Ascospore

  21. Penicilliumnotatumsexual spores Cleistothecium (enclosed fruiting body) Ascus with ascospores

  22. Fungi Classification • Kingdom Mycetae (Fungi) • Division Amastigomycotina • B. Subdivision Ascomycotina • 3. Penicilliumnotatum- phialospore (asexual spore) • Phialospores • Phialophore • Phialide • Metulae • Septa • Hyphae

  23. Penicilliumnotatumasexual spores Phialospores Phialide Phialophore

  24. PENICILLIUM • (Latin for penicillus = “paint brush”) • The branches off its phialophores are called metulae. This mold is famous for its use by Alexander Fleming in making penicillin, but it is also used to make aged cheeses like Brie, Blue cheese, and Roquefort. • The white top layer of Brie cheese is where the vegetative hyphae are. The cheese is made with lactic acid bacteria (the curd is the cheese) and it is inoculated with Penicillium for flavor. • The colony of Penicillium is green with a white ring.

  25. Penicillium

  26. Penicillium Penicillium

  27. Fungi Classification • Kingdom Mycetae (Fungi) • Division Amastigomycotina • B. Subdivision Ascomycotina • 5. Morchella spp- ascospores (sexual spore) • Hyphae • Ascus • Ascospore

  28. Morchella • Edible mushrooms with honeycomb appearance. • Mushroom hunters refer to them by their color (e.g., gray, yellow, black morels) Black Morel Yellow Morel

  29. Fungi Classification • Kingdom Mycetae (Fungi) • Division Amastigomycotina • B. Subdivision Ascomycotina • 6. Aspergillus niger - phialospore (asexual spore; a type of conidiospore) • Phialospores • Phialophore • Hyphae • Vesicle • Phialide

  30. Aspergillus

  31. Aspergillus • Aspergillus gets its name from “aspergillum”, the name of the item a Priest uses to bless with Holy water. Aspergillus is a very common fungi, pervasive (found everywhere). There are more than 600 species. Most are saprobic (non-pathogenic) and live off dead matter. In a young fruiting body, the “handle” of the conidia is called the conidiophore. The bulb at the top is called the vesicle. The philiae radiate out from the vesicle, and the spores form chains in the philiae. The older fruiting bodies look like a toilet brush because they are covered with spores at all angles.

  32. Aspergillum

  33. Aspergillus • Some Aspergillus fungi can ferment. That’s where we get citric acid for soft drinks and also soy sauce. • One pathogenic species is called Aspergillus flavus. It produces a toxin called aflatoxin (a mycotoxin) which is carcinogenic, especially in the liver (liver cancer). This species is fond of grains (corn, wheat), and peanuts, and jelly. Therefore, a peanut butter and jelly sandwich is a triple whammy for aflatoxin. It dissolves in the jelly, so scooping it off the top surface of the jar will not do any good. • To prevent aflatoxin, only buy peanut butter and jelly in the size jars you use up in a week, keep them refrigerated (the bread, too), and use a clean knife each time. Don’t leave the lid off for long, because that’s when it gets in. • Another disease Aspergillus causes is aspirgillosis, a lung disease.

  34. Aspergillosis • Aspergillosis: can occur anywhere in the body, but is most common in the lungs. • Some people just have allergies to this mold. • X-ray of aspergillosis shows aspergilloma (“fungus balls”) which are mycelium and white blood cells. • Although opportunistic diseases are usually seen in immunocompromised people, healthy people who are overexposed can also get sick. • Since this mold loves grains, farmers are especially at risk.

  35. Aspergillus

  36. Aspergillus Aspergillus

  37. Aspergillus

  38. Aspergillosis

  39. Aspergillosis Aspergilloma (Fungus balls)

  40. Fungi Classification • Kingdom Mycetae (Fungi) • Division Amastigomycotina • B. Subdivision Ascomycotina • 7. Saccaromycescerevisiae -yeast- (asexual spore) • Parent cell • Blastospore

  41. Saccaromyces (“sugar mold”) cerevisiae (“beer”)

  42. Saccharomycescerevisiae

  43. Fungi Classification • Kingdom Mycetae (Fungi) • Division Amastigomycotina • A. Subdivision Zygomycota • B. Subdivision Ascomycotina • C. Subdivision Basidiomycota • D. Subdivision Deuteromycota

  44. Fungi Classification • Kingdom Mycetae (Fungi) • Division Amastigomycotina • C. Subdivision Basidiomycota • Club fungi; mushrooms, rusts, smuts. • 8. Coprinus spp. • Basidium • Basidiospores • Basidiophore • Hymenium • (cup area where spores develop)

  45. Coprinus (mushroom)

  46. Coprinus with Basidiospores Coprinus

  47. Coprinus with Basidiospores

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