FILAMENTOUS ASCOMYCETES I IB 371 - General Mycology Lecture 21 Thursday, November 6, 2003 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 SEPTAL PORE


MEIOSIS & ASCOSPOROGENESIS In-class activity How is a crozier like a clamp connection?

ASCOGONIA TEM of crosier by Charles Mims Crosiers & Developing

Asci TEM of developing ascus by Charles Mims TEM of ascospores developing within an ascus by Charles Mims TEM of maturing ascospores within an ascus by Charles Mims

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 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

Hamathecium None Paraphyses Apical paraphyses Pseudoparaphyses

Catenophyses 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) 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 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 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 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)

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 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

dimorphic - yeast stage 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 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 Conidium of H. capsulatum Yeast stage of H. capsulatum VALLEY FEVER

aka desert rheumatism, California disease occurs in desert SW, Mexico, SA Coccidioides immitis (only imperfect state

known, connected to Onygenales by 18S rDNA sequences) Inhalation of conidia (arthrospores), symptoms somewhat similar to histoplasmosis

Most people recover but sometimes the disease is fatal 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

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 EUROTIALES Ubiquitous in distribution

Found commonly in soils and on plant litter

Associated with cellulosic, starchy or oily substrates EUROTIALES Decomposers

Agents of biodeterioration

Human pathogens (aspergillosis, penicilliosis) Aflatoxin & ochratoxin production

EUROTIALES Important in cheese industry

Production of industrially important acids (citric, gallic, fumaric, oxalic, gluconic), and enzymes (alphagalactosidase) Production of antibiotics (penicillin,

cephalosporin, griseofulvum PENICILLIUM Teleomorph genera Eupenicillum Talaromyces

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

ASPERGILLUS Teleomorph genera Eurotium Neosartorya Emericella

Eurotium/Aspergillus ASPERGILLUS Conidial state of Aspergillus (Picture from David Geiser)

Hlle cells (picture from David Geiser) Young conidiophores of Aspergillus (SEM from Charles Mims)

Mature conidiophores of Aspergillus (SEM from Charles Mims) SEM of conidiogenesis in Aspergillus (from Charles Mims) SEM of conidiogenesis in Aspergillus (from Charles Mims) EUROTIUM ASCI

ASCOSPORES OF EUROTIUM From Hanlin, 1998. Illustrated Genera of Ascomycetes Vol II

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