Microbiology 205 Georgetta Seidel

1. Microbiology 205 Georgetta Seidel

2. Definitions • Mycologists--scientists who study fungi • Mycology--scientific discipline dealing with fungi • Mycoses--diseases caused in animals by fungi

5. The five kingdom system • Eukarya (includes all organism with a nucleus & membrane bound organelles) • Plants and Animals are fairly obvious • Fungi, are very distinct from the other kingdoms • Kingdom Protista is a “dumping ground” for organisms that don’t fit into the other eukaryotic kingdoms

7. Exoenzymes are found in fungi and some bacteria. They are digestive enzymes that are secreted into the environment, where they digest the food into small molecules that can be absorbed and used by the fungus.

9. FUNGI 100,000 species 100 human pathogens, fungi associated diseases are rising, due to nosocomial infections and in immunocompromised patients (ie. HIV, diabetes, lupus, transplant folks) Aspergillosis, Blastomycosis—pulmonary infections and dissemination may be involved 5,000 plant pathogens=$1 billion/yr

10. IMPORTANCE OF FUNGI • Fermentation industry • Remember fermentation is an anaerobic process • Wine (yeast) • Beer • Bread • Cheese (bacteria) • Soy sauce (filamentous fungi (Aspergillus oryzae provides a low protein diet with amino acids, yeast & bacteria) soy beans & flour are held in a container for mold to grow—moldy beans are incubated for several months • Sauerkraut • Vinegar (yeast and bacteria) • Yoghurt (Bacteria)

11. IMPORTANCE OF FUNGI • Drug manufacturing (usually their waste products are to our benefit) • Citric acid • Ethanol (yeast) • Antibiotic griseofulvin, penicillin • Cortisone (Rhizopus) • immunosuppressive agents (cyclosporine)

12. IMPORTANCE OF FUNGI (cont.) • SAPROPHYTE • Degrade complex organic materials into simple ones, which become available for other organisms

13. Importance of Fungi (cont.) • MYCORRHIZAE • Fungi associated with plants Symbiosis • Fungi help plant roots absorb minerals and water in the soil-serve as root extensions • Fungi benefit by absorbing nutrients exuded by plant roots

16. They are often called “ancient plants” • 4 broad classes exist • Algal fungi • Sac fungi • Imperfect fungi • Club (basidium) fungi

17. Algal fungi • All are microscopic and grow in water and damp soil • Many species in this group are responsible for blights (like Irish Potato Famine) • Some species, such as Rhizopus however, are used as a source of cortisone and other "drugs"

18. Sac fungi • yeasts and the blue and green molds often seen on decaying citrus fruits, in jellies and on leather • Some species, like Penicillium are economically useful, but others such as Ergot (Clavicep s purpurea) which infects rye crops, can cause mass destruction • In controlled doses, however, Ergot becomes an important alkaloid used to control hemmorrage (during the birthing process) as well as in the treatment of migraine • Candida albicans is another species of sac fungi that is parasitic in human beings and aids in the normal functioning of the digestive tract

19. Imperfect fungi • molds that mildew walls and spot clothes, as well as those that cause plant diseases, athlete's foot, and ringworm. • Some of these fungi are useful like Aspergillus, used in the production of miso (fermented soy paste)

20. Club (basidium) fungi • largest group of fungi which includes rusts and smuts that attack specific plants, such as corn, beans, apples, wheat, asparagus, coffee, roses and barberry • many of the mushrooms in this division are edible and delicious, a large number of them, such as the Amanita's are deadly poisonous

22. FUNGAL STRUCTURE • Thallus-”body” • Molds & fleshy fungi have these structures • Long filaments of cells (hyphae) • Septate-Cross Wall (Most Fungi) • Coenocytic-No cross wall, continuous mass with many nuclei

25. MYCELIUM • Intertwined filamentous mass formed by hyphae, visible to the unaided eye • Forms when environmental conditions are right

27. YEAST Facultative Anaerobes • Fermentation=ethanol and CO2 • Non-filamentous unicellular fungi • Spherical or oval • Reproduction • Two types exist • a)Fission or b) budding

28. Yeast Reproduction • FISSION • “even” reproduction, nucleus divides forming two identical cells, like bacteria • BUDDING • “uneven” reproduction, parent cell’s nucleus divides and migrates to form a bud and then breaks away

30. DIMORPHIC FUNGI • Growth as a mold or as a yeast • Most pathogenic fungi are dimorphic fungi • At 37o C yeast-like • At 25o C mold-like • Can also occur with changes in CO2 • Fungi grow differently in tissue vs nature/culture; often dictated by temp

31. Changes in CO2 Within Agar=mold, Agar Surface=yeast

32. Types of REPRODUCTION • Asexually-fragmentation of hyphae • Asexually and Sexually-spores • Spores: Used for Identification Four groups of true fungi • Zygomycetes (common bread mold—Rhizopus) • Basidiomycetes (puffballs & common mushrooms) • Ascomycetes (Dutch elm disease/rye smut) • Deuteromycetes (fungi imperfecti)

33. Classification of these groups • First three groups is based on their method of sexual reproduction • 4th group, the Deuteromycetes, have NO sexual reproduction

34. REPRODUCTION (cont.) • Asexual Reproduction • Progeny will be identical to parent • Spores (Conidiospores, Blastospores,Chlamydospores, Sporangiospores) • Hyphae fragmentation (Arthrospores)

35. IDENTIFICATION OF FUNGI • Examination of asexual spores • **Fungal spores are different than the endospores of bacteria • Endospores are not for reproduction, but an environmentally resistant life stage • Fungal spores are for reproduction, do not ensure resistance to environmental conditions

36. Asexual spores • Conidiospores • Chlamydospores • Sporangiospores • Blastospores

37. ASEXUAL SPORES Conidiospore • Multiple (chains) or single spores formed at the end of an aerial hypha • Not enclosed within a sac • Aspergillus spp. • Penicillium spp.

38. Conidial fungus • reproduces by means of asexual spores called conidia • Conidia vary greatly in shape, size and color • Most of the common household molds & mildews are conidial fungi

39. ASEXUAL SPORES (cont.) • Another type of Conidiophore: • Blastospores • A bud coming off the parent cell • Candida albicans Blastospore

40. Blastospores

41. ASEXUAL SPORES (cont.) • Chlamydospore • Formed within hypha • Thick-walled spore • Candida albicans

42. Chlamydospores • The chlamydospore is a method of producing a substantial resting spore very quickly • Nutrient is shunted from adjacent cells into a preferred cell and it swells up, converts nutrient materials to oil droplets for efficient storage, then rounds off with a thick, often roughened outer wall for protection

43. Chlamydospores

44. ASEXUAL SPORES • Sporangiospores • Hundreds formed within a sac (sporangium) at the end of an aerial hypha • Rhizopus spp.

46. Rhizopus spp

47. Arthrospores 1A 2 Chlamydospores 1 Conidiospores 3 1B Blastospores Sporangiospores

48. NUTRITIONAL ADAPTATIONS • Acidic pH (5.0) • Most molds are aerobic • Yeasts are facultative anaerobes

49. NUTRITIONAL ADAPTATIONS (cont.) • High osmotic pressure • Low moisture • Less N2 than bacteria • Complex carbohydrates • Lignin(component of wood) *Saprophytes