1. FILAMENTOUS ASCOMYCETES I
IB General Mycology
Lecture 21
Thursday, November 6, 2003

2. FILAMENTOUS ASCOMYCETES
Mycelium septate
Septa with single pore or many small pores
Woronin bodies present at pores
Nuclei haploid, except during meiosis
Antheridia & ascogonia may or may not be formed prior to meiosis
Ascogenous hyphae formed

3. SEPTAL PORE

4. Woronin Bodies

5. NUCLEUS PASSING THROUGH PORE

6. GENERAL LIFE CYCLE

8. MEIOSIS & ASCOSPOROGENESIS

10. In-class activity
How is a crozier like a clamp connection?

11. ASCOGONIA

13. TEM of crosier by Charles Mims

14. Crosiers & Developing Asci

15. TEM of developing ascus by Charles Mims

16. TEM of ascospores developing within an ascus by Charles Mims

17. TEM of maturing ascospores within an ascus by Charles Mims

22. TYPES OF ASC0MATA Cleistothecium - round & completely closed
Apothecium - open & saucer shaped
Perithecium - flask shaped with an opening at the top
Pseudothecium - may look like a perithecium but it is stromatic & is formed prior to the ascogenous hyphae

23. TYPES OF ASCI
Prototunicate - one functional wall that deliquesces early
Unitunicate - one functional wall that remains as one wall when ascospores are discharged
Bitunicate (fissitunicate) - two functional walls that separate when ascospores are discharged

24. Hamathecium None Paraphyses Apical paraphyses Pseudoparaphyses
Catenophyses

25. ONYGENALES
Sexual apparatus - antheridium surrounded by a coiled ascogonium
Homothallic or heterothallic
Asci unitunicate, globose to subglobose
Ascus wall breaks down to release ascospores (deliquescent)
Ascospores usually non-septate (amerospores)

26. ONYGENALES
Ascoma is a cleistothecium of thin cottony hyphae or very thin layer of pseudoparenchyma tissue
Peridial hyphae (peridium = wall of cleistothecium) similar to vegetative hyphae, colored and/or rough walled

27. ONYGENALES
Anamorphs are solitary holoblastic (determinate) or arthric (thallospores)
Taxonomic characters - peridial wall ornamentation, ascospore characters
Ecology - keratinophilic, cellulolytic - saprophytes and parasites of animals
Habitat - soil, plant debris, faecal pellets of carnivores, birds’ nests and droppings, hoofs and horns

35. PATHOGENS OF HUMANS ringworm (tinea), athletes foot, jock itch
Trichophyton (A)/ Arthroderma (T)
Microsporum (A)/ Nannizzia (T)
Geophilic - soil inhabiting species that are only occasionally pathogenic to humans
Zoophilic - live on animals but occasionally infect humans
anthropophilic - species that live only on humans

36. DERMATOPHYTES
Keratinophylic - live on hair, nails, dead skin cells (protein keratin)
Symptoms caused by enzymes that irritate epidermal cells
Treatment may be systemic (griseofulvum) or topical (azole antifungals, ciclopirox, others)

38. NORTH AMERICAN BLASTOMYCOSIS
Blastomyces dermatitidis (A) / Ajellomyces dermatitidis (T)
Thought to occur in soil in midwest, US-Canadian border from the Great Lakes to the east coast.
Infection through inhalation of conidia into the lungs

39. NORTH AMERICAN BLASTOMYCOSIS
fever, chills, cough, chest pain, pneumonia (sometimes fatal), skin lesions
fungus is dimorphic - filamentous in nature, yeast-like in body (or above 30C)
Itraconazole daily for six months or if life threatening, amphotericin B

40. dimorphic - yeast stage

41. HISTOPLASMOSIS
Histoplasma capsulatum (A) / Emmonsiella (Ajellomyces) capsulatum
Grows as hyphae in soil enriched with bird droppings
Ohio and Mississippi river valleys, Great Lakes to east coast, Florida, Texas
Infection by breathing in conidia

42. HISTOPLASMOSIS most people remain asymptomatic
fever, chills, headache, chest pain, malaise, nodules in the lung
chronic pulmonary histoplasmosis mimics TB (diagnosis is very important)
acute disease requires treatment with amphotericin B, followed by itraconazole
immunocompromised patients require lifelong treatment if infected

43. Conidium of H. capsulatum

44. Yeast stage of H. capsulatum

45. VALLEY FEVER
aka desert rheumatism, California disease - occurs in desert SW, Mexico, SA
Coccidioides immitis (only imperfect state known, connected to Onygenales by 18S r-DNA sequences)
Inhalation of conidia (arthrospores), symptoms somewhat similar to histoplasmosis
Most people recover but sometimes the disease is fatal

46. EUROTIALES Asci free on mycelium or in ascomata
Ascomal wall thin, mesh-like or solid layer
Sexual fusion usually by a trichogyne and undifferentiated hypha
Asci spherical to ovoid, evanescent

48. EUROTIALES Ascospores 1-celled, oblate, spherical, globose
Ascospores smooth or with reticulations, spines or thickened rings
Conidial states phialidic, conidia seceding schizolytically, in dry chains

49. EUROTIALES Ubiquitous in distribution
Found commonly in soils and on plant litter
Associated with cellulosic, starchy or oily substrates

50. EUROTIALES Decomposers Agents of biodeterioration
Human pathogens (aspergillosis, penicilliosis)
Aflatoxin & ochratoxin production

51. EUROTIALES Important in cheese industry
Production of industrially important acids (citric, gallic, fumaric, oxalic, gluconic), and enzymes (alpha-galactosidase)
Production of antibiotics (penicillin, cephalosporin, griseofulvum

52. PENICILLIUM
Teleomorph genera –
Eupenicillum
Talaromyces

53. Discovery of penicillin
Changed the world.
In 1928, Alexander Fleming found P. notatum growing on a Petri dish (dish is still preserved).
In 1939, Howard Florey & Ernest Chain began work on how to use and identify the antibiotic produced by P. notatum.
In 1941, work began in Peoria, IL, to increase production of the antibiotic. “Moldy Mary” brought in a moldy melon colonized by the high yielding species, P. chrysogenum.

54. Discovery of penicillin
In 1942, the first patient was treated successfully in New Haven, Connecticut (Anne Miller).
In 1945, Fleming, Florey & Chain received the Nobel Prize for their work.

57. PENICILLIUM

58. From Hanlin, 1998. Illustrated Genera of Ascomycetes Vol II

59. From Hanlin, 1998. Illustrated Genera of Ascomycetes Vol II

60. ASPERGILLUS
Teleomorph genera -
Eurotium
Neosartorya
Emericella

61. Eurotium/Aspergillus

62. ASPERGILLUS

63. Conidial state of Aspergillus (Picture from David Geiser)
Conidial state of Aspergillus (Picture from David Geiser)

64. Hülle cells (picture from David Geiser)

65. Young conidiophores of Aspergillus (SEM from Charles Mims)
Young conidiophores of Aspergillus (SEM from Charles Mims)

66. Mature conidiophores of Aspergillus (SEM from Charles Mims)

67. SEM of conidiogenesis in Aspergillus (from Charles Mims)

68. SEM of conidiogenesis in Aspergillus (from Charles Mims)

69. EUROTIUM ASCI

70. ASCOSPORES OF EUROTIUM

71. From Hanlin, 1998. Illustrated Genera of Ascomycetes Vol II