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Ascomycota (continued) MIKROSKOPIK YEAST, RAGI, KHAMIR… DLL KULIAH 7.

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Presentation on theme: "Ascomycota (continued) MIKROSKOPIK YEAST, RAGI, KHAMIR… DLL KULIAH 7."— Presentation transcript:

1 Ascomycota (continued) MIKROSKOPIK YEAST, RAGI, KHAMIR… DLL KULIAH 7

2 PEMBAGIAN ASCOMYCOTA Class 1: Laboulbeniomycetes parasitic attachments to arthropods. Class 2: Protoascomycetes lack of ascogenous hyphae and ascomata. Class 3: Euascomycetes most of the fungi which form ascomata. The orders are separated on the structure of the ascus and the manner of ascus opening. ascus

3 From Spatafora et al A five-gene phylogeny of Pezizomycotina. Mycologia 98:

4 Filamentous ascomycetes Sacccharomycetales Archiascomycetes Basidiomycetes Characterized by DNA sequence analysis Ascocarps; ascogenous hyphae; specialized ascus tip; conidia; Woronin bodies Absence of ascogenous hyphae and ascocarps; most asci without specialized tips Classification from Alexopoulos et al. 1996

5 RAGI Ascomycetous yeasts Characterized by absence of ascogenous hyphae and ascocarps Asci mostly prototunicate Occur in slime fluxes, nectar, fresh or decaying fruit—able to grow in high osmotic conditions (high sugar content) Others occur in soil, dung, water, digestive tracts of animals Many species are symbiotic with insects

6 Schizosaccharomyces

7 Saccharaomyces

8 Somatic structures Yeast A single-celled fungus that reproduces by budding (or fission) A single-celled fungus that reproduces by budding (or fission)Pseudomycelium Series of cells adhering after budding Series of cells adhering after budding

9 Budding Bipolar Multilateral

10 Asexual reproduction ConidiaArthrospores

11 plasmogamy copulation karyogamy budding 2n somatic cells meiosis Mature ascus 1n somatic cells

12 Identification Microscopic appearance Unicellular or budding Unicellular or budding Size & shape of yeast cells Size & shape of yeast cells Multilateral or bipolar budding Multilateral or bipolar budding Form, structure and mode of ascus formation Form, structure and mode of ascus formation Ascospore shape Ascospore shape

13 Identification Physiological tests—91 different tests Ferment different sugars Ferment different sugars Assimilation tests (carbon and nitrogen source) Assimilation tests (carbon and nitrogen source) Vitamin requirements Vitamin requirements Growth at 37C Growth at 37C Growth in cyclohexamide Growth in cyclohexamide Hydrolyse urea Hydrolyse urea Form acid Form acid

14 Importance BrewingBaking Food production Industrial applications Model systems (S. cerevisiae) Probiotics Animal pathogens

15 MICROSCOPIC(NON-YEAST)

16 From Hanlin, Illustrated Genera of Ascomycetes Vol II Ascospore by D. Geiser Aspergillus anamorph Cleistothecia yellow to orange-red Wall composed of single layer of flattened cells Ascospores flattened, usually with equatorial groove. Eurotium

17 Aspergillus anamorph Cleistothecial wall surrounded by hülle cells Ascospores small, colored, lens-shaped with flange From Hanlin, Illustrated Genera of Ascomycetes Vol II Emericella

18 Emericella Hülle cells, D. Geiser

19 Anamorphs--Aspergillus SEM by Charles Mims

20 Penicillium anamorph Cleisothecia hard, white becoming colored (yellow, orange, brown) Ascospores small, hyaline or yellowish, lens-shaped From Hanlin, Illustrated Genera of Ascomycetes Vol II Eupenicillium

21 Image by David Geiser

22 Anamorphs--Penicillium phialides Branches (metulae)

23 From Hanlin, Illustrated Genera of Ascomycetes Vol II Talaromyces Paecilomyces or Penicillium anamorph Cleistothecium whitish to bright yellow Wall composed of interwoven hyphae Ascospores ellipsoidal, with spiny walls

24 Anamorphs--Paecilomyces Divergent phialides with swollen base and long, tapering neck Colonies may be pink, purple, yellow, brown or white, but never green as in Penicillium spp.

25 The good and the bad Penicillium spp.—antibiotic production Penicillium roqueforti—blue cheese Penicillium spp.—blue and green molds on bread, cheese, fruits, vegetables Aspergillus flavus—aflatoxins (moldy peanuts) A. flavus/A. niger--aspergillosis

26

27 Penicillin Penicillium notatum growing in Alexander Fleming’s Petri dish of Staphylococcus in 1928 led to the discovery of penicillin Howard Florey & Ernest Chain (1939) began work on purification and trials 1941—work moved to US (NRRL in Peoria, IL) to escape bombing in London (WWII) Fermentation vessels and corn steep liquor Fermentation vessels and corn steep liquor Mary Hunt (“Moldy Mary”) brought in P. chyrogenum on a melon Mary Hunt (“Moldy Mary”) brought in P. chyrogenum on a melon 1945—Fleming, Florey & Chain received Noble Prize

28 Penicillium notatum Penicillin prevents cross-linking of small peptide chains in peptidoglycan, the main wall polymer in bacteria. Newly formed cells are abnormal in shape and susceptible to osmotic lysis.

29 Fungal taxon/groupEst. # species# known metabolites Aspergillus, Eurotium, Emericella Penicillium, Talaromyces, Eupenicillium Trichoderma, Hypocrea2054 Cephalosporium-like hyphomycetes Mucor, Rhizopus, Phycomyces7026 Oomycetes, Chytridiomycota4503 Yeasts60050 Basidiomycetes30,000300

30 POWDERY MILDEW Biotrophs of vascular plants Biotroph: an obligate parasite growing on another living organism Biotroph: an obligate parasite growing on another living organism 21 genera, 437 species infecting > 40,000 species of plants (mostly dicots) Most species are host specific, a few are omnivorous, infecting hundreds of host species

31 Powdery Mildew Symptoms Photo by Claudia Nitschwitz

32 Characteristics Mycelium is mostly superficial Anchored to host epidermis by appressoria Anchored to host epidermis by appressoria Nutrients obtained via haustoria Haustoria are intracellular structures Haustoria are intracellular structures Overwinter as mycelium in infected buds or as ascomata Asexual reproduction via conidia Sexual reproduction via ascospores formed in cleistothecia

33 Asexual reproduction Erect, hyaline conidiophores are usually formed on superficial mycelium; One-celled, hyaline thin-walled conidia are produced holoblastically in basipetal chains One colony can produce > 30,000 conidia

34 Conidia Wind-dispersed Germination can occur at low relative humidity Germination involves germ tube, appressorium and penetration peg formation Apex of penetration peg enlarges to form haustorium

35 From APSnet.org

36 Plant cell wall Plasma membrane Host cytoplasm Plasma membrane haustorium appressorium Penetration peg fungus

37 Microsphaera alni anamorph on Vaccinium

38 Sexual reproduction Cleistothecia formed on superficial mycelium in late summer/early fall Asci Formed in basal layer Formed in basal layer Globose to pyriform Globose to pyriform Discharge of spore by rupture of ascus tip Discharge of spore by rupture of ascus tip

39 Asci/Ascospores One to numerous asci/cleistothecium Ascospores hyaline, one-celled, ovoid 1-8 ascospores/ascus Number of asci/cleistothecium is important character in identification

40 From APSnet.org

41 Identification Anamorph type Number of asci/ascocarp Cleistothecial appendages Mycelioid Mycelioid Rigid Rigid Spear-like with inflated base With curled tips With dichotomously branched tips

42 Microsphaera alni cleistothecia

43 Sawadaea bicornis cleistothecia

44 Sawadaea bicornis cleistothecial appendages

45 Mycelioid Appendages Several asci/ascocarp: Eryisiphe (100 spp) Eryisiphe (100 spp) Oidium anamorph One ascus/ascocarp: Sphaerotheca (50 spp.) Sphaerotheca (50 spp.) Appendages with curled tips Oidium anamorph

46 Dichotomously branched appendage tips One ascus/ascocarp: Podosphaera (12 spp.) Podosphaera (12 spp.) Oidium anamorph Several asci/ascocarp: Sawadaea (6 spp.) Sawadaea (6 spp.) Oidium anamorph

47 Spear-like appendages-- Phyllactinia Ovulariopsis and Streptopodium anamorphs

48 Appendages with curled tips Uncinula (81 spp) Oidium anamorph Oidium anamorph Several asci/ascocarp Several asci/ascocarp


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