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About the course
• syllabus
• website: HMB436H – Medical & Veterinary Mycology
http://individual.utoronto.ca/jscott/courses/medmyco/medmyco.html
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Dr. James Scott
Dalla Lana School of Public Health
University of Toronto
lectures (lots)
lectures
(lots)
readings (lots)
tests (2)
assignments (5)
2
More about your assignments
1.
2.
3.
4.
5.
Wikipedia
• Handout
Set up account/ orientation (Sept 18) (5%)
Online Interactive Training (Sept 25) (5%)
Fact outline and references (Oct 16) (5%)
Peer commentary (Oct 30) (5%)
Final article (Nov 5) (15%)
– Welcome to Wikipedia
– search wikipedia:introduction
• Homework (complete this by Friday September 18, 2014)
– Get a Wikipedia account
– Enrol in the Wikipedia component of the course
– Email me your user name (james.scott@utoronto.ca)
to find me, search user:medmyco
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Now to the main part of the course
Now to the main part of the course
HMB436H – Medical & Veterinary Mycology
Lecture 1 – Fungi form & function
Dr. James Scott
Dalla Lana School of Public Health
University of Toronto
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Amanita muscaria
© Michael Wood (2004)
Cladonia cristatella
© Ron Cillizza (2003)
Geastrum sp., North Carolina
Ritas Vilgalys
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Aleuria rhenana
© Taylor F. Lockwood (2004)
Penicillium digitatum
Penicillium chrysogenum
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Bacteria
Cyanobacteria
Archaeglobus
Clostridium
Mycoplasma
Methanobacterium
Methanococcus
Thermologa
Cordyceps militaris
Joey Spatafora
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Fungi
Slime moulds
Pyrococcus
Deinococcus
Green nonsulfur
bacteria
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Animals
Plants
Pyrobaculum
Borrelia
photographersdirect.com
Eukarya
Archaea
Purple Gram
bacteria positives
Termitomyces titanicus
Flagellates
Trichomonads
Microsporidia
Aquifex
Origin
Source: Oak Ridge National Laboratory
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*
*
*
Hibbett et al. Mycol Res 111 (2007): 509‐547
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Most are filamentous (more about this later)
Form & function
Hypha (plural "hyphae")
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hypha
Cell wall composition of some "fungal" groups
mitochondrion
Phylum
Fibrillar components
Matrix components
Oomycota
Cellulose, beta‐(1,3) / beta‐
(1,6)‐d‐glucans
Glucan
Chtrydiomycota
Chitin, Glucan
Glucan
Zygomycota
Chitin, Chitosan
Polyglucuronic acid, glucuronomannoproteins
Ascomycota
Chitin, beta‐(1,3) / beta‐
(1,6)‐d‐glucans
alpha‐(1,3)‐d‐glucan,
galactomannoproteins
Basidiomycota
Chitin, beta‐(1,3) / beta‐
(1,6)‐d‐glucans
alpha‐(1,3)‐d‐glucan,
xylomannoproteins
NOTE: chitin = poly‐N‐acetylglucosamine
From Deacon
nucleus
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Nutrient uptake
Enzyme
secretion
Fungi are heterotrophic and digest their food outside their cells
this is the
stomach
Release of metabolites
and antimicrobial materials
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Filamentous
growth
They can have multiple growth forms
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Hypha
Yeast
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Spores
• can arise from sexual reproduction (meiosis)
– e.g., ascospores, basidiospores, zygospores
Spores
• can be asexually produced
– sporangiospores
i
(i
(in Zygomycota)
)
• always produced internally in a sporangium
– conidia (in Ascomycota and some Basidiomycota)
• conidia are hyphae that have become modified through evolution for dispersal purposes
• they are always produced externally on a conidiophore
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Sexual reproduction
• most fungi are vegetative haploids
– a few are diploid, like the yeast Candida albicans
• sexual reproduction
– compatible mycelia fuse by anastomosis
ibl
li f
b
i
– one mycelium receives one or more compatible haploid nuclei (this cell becomes a dikaryon)
– the nuclei either undergo meiosis immediately (e.g., Ascomycota), or the mycelium continues to grow and mating occurs later (Basidiomycota)
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Phylogenetic organization
Hibbett et al. Mycol Res 111 (2007): 509‐547
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Chytridiomycota
Percentage of tota
al estimated
number of species
s known (%)
Estimated completeness of taxonomic knowledge for some common groups
100
90
80
70
60
50
40
30
20
10
0
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Mammals
Insects
Vascular plants
Algae
Fungi
Bacteria
Viruses
• mostly aquatic, typically fresh water
• largely saprotrophic, but many parasites of plants (e.g., roots, pollen grains, etc.)
• Synchytrium endobioticum (potato wart disease)
• Batrachochytrium dendrobatidis
h h i
d d b idi (amphibian decline)
Taxonomic category
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Zygomycota (Mucoromycotina)
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Zygomycota
Rhizopus
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Reproduction in Zygomycota
• hyphae mostly lack septa (coenocytic)
• "Zygomycota" includes 5 phylogenetic groups
– Mucormycotina
• mostly saprotrophs but some parasites
tl
t h b t
it
• very fast growing, like simple sugars, some like ↑ temp
– Entomophthoromycotina
• sexual reproduction by zygospores
– two compatible gametangia meet, grow apart, then grow towards each other and anastomose
– Their nuclei move to a central cell which becomes Their nuclei move to a central cell which becomes
a zygosporangium, containing a single zygospore
– the emptied gametangia are called suspensors
• asexual reproduction by sporangiospores
• sophisticated insect pathogens
– Glomeromycotina
– borne inside a stalked sac called a sporangium
– can be a single or multiple, some are very fancy
• symbionts of plant roots
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Rhizopus oligosporus
Zygospores of Rhizopus sp.
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Rhizopus sp.
Sporangia & sporangiospores
Patrick Roper
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Basidiomycota
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Basidiomycota
Cortinarius armillatus
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Basidiomycota
• asexual reproduction by conidia (modified hyphae), yeasts, but many lack asexual forms
• sexual reproduction by basidiospores
– produced externally on a basidium
– conidial forms include Sporotrichum
– yeast forms include Sporomolomyces & Cryptococcus
• can produce a vegetative dikaryon
can produce a vegetative dikaryon
– dikaryotic hyphae often have clamp connections
– hyphae always septate
• lots are saprotrophs, especially causing wood rot
• others are plant symbionts or parasites
• more about these in another lecture
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Clamp connection formation
Dikaryotic hypha
(2 different nuclei per cell)
From Wong: http://www.botany.hawaii.edu/faculty/wong/Bot201/Basidiomycota/Clamp_connection_formation.htm
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Ascomycota
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Ascomycota
Scutellinia scutellata
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Ascomycota
• sexual reproduction by ascospores
• Sexual spores (ascospores) develop in sacs called asci (sing. ascus)
– produced inside an ascus (pl. asci)
– asci grow inside (or on) the ascoma (pl. ascomata)
• Commonly called "cup fungi"
Commonly called "cup fungi"
– floppy cup‐like fruiting bodies called apothecia
– but far more make tiny whisker‐like ascomata
• ones with necks are called perithecia or pseudothecia
• ones that are entirely closed are called cleistothecia
• ones like little "tumbleweeds" are called gymnothecia 47
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Podosphaeria
Mark Double (WVU)
Cryphonectria parasitica
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Ascomycota
• only exist as vegetative monokaryons
– NEVER have clamp connections
• many Ascomycota have asexual forms
– asexual reproduction by mitotic spores (conidia)
l
d i b i i
( idi )
– their structure is often highly specialized
– some fungi only make conidia (e.g., moulds)
• vast ecological diversity
– saprotrophs, parasites, mutulists
Myxotrichum deflexum
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Their naming can be complicated
Talaromyces
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=
Penicillium
sexual stage called:
asexual stage called:
teleomorph
anamorph
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