Download Fungi

VBP035 Perform
Microbiological
Procedures in the
Food Industry
CRICOS Provider Code: 01505M
RTO Number: 3045
DHS V1.2 2011
L 4b
Fungi
CRICOS Provider Code: 01505M
RTO Number: 3045
IV. Fungi
2. Classification
- Chytridiomycota
- Zygomycota
- Ascomycota
- Basidiomycota
Single celled members of these groups are all called
“yeasts”. They are distinguished from protists based
on a chitinous cell wall and absorptive (rather than
phagocytic) nutrition.
CRICOS Provider Code: 01505M
RTO Number: 3045
IV. Fungi
3. General Biology
- The organism is composed of threadlike
“hyphae”
CRICOS Provider Code: 01505M
RTO Number: 3045
IV. Fungi
3. General Biology
- The organism is composed of threadlike
“hyphae”
- The hypha can be coenocytic (without
divisions)
or septate (with incomplete cell walls
between)
CRICOS Provider Code: 01505M
RTO Number: 3045
IV. Fungi
3. General Biology
- The organism is composed of threadlike
“hyphae”
- The hypha can be coenocytic (without
divisions)
or septate (with incomplete cell walls
between)
- These have a huge surface area/volume ratio
for absorption.
- The largest organisms known… 37 acres.
CRICOS Provider Code: 01505M
RTO Number: 3045
Fungal reproduction
Asexually, by forming conidia
Sexually (three steps):
•Plasmogami (dikaryon)
•Karyogami (zygote forms)
•Meiosis (sexual spore forms):
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RTO Number: 3045
•Zygospore
•Ascospore
•Basidiospore
Zygomycota
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RTO Number: 3045
IV. Fungi
4. Ecological Roles
- decomposers: Fungi decompose lignin and
cellulose, which most free-living bacteria can’t digest.
CRICOS Provider Code: 01505M
RTO Number: 3045
IV. Fungi
4. Ecological Roles
- decomposers: Fungi decompose lignin and
cellulose, which most free-living bacteria can’t digest.
* antibiotics
CRICOS Provider Code: 01505M
RTO Number: 3045
IV. Fungi
4. Ecological Roles
- decomposers: Fungi decompose liginin and
cellulose, which most free-living bacteria can’t digest.
* antibiotics
- mycorrhizae: fungal symbiotes of certain plants. The
fungus increases the absorbance area of roots
dramatically, and passes water and nutrients to the plant.
The plant feeds the fungus with glucose.
CRICOS Provider Code: 01505M
RTO Number: 3045
IV. Fungi
4. Ecological Roles
- decomposers: Fungi decompose liginin and
cellulose, which most free-living bacteria can’t digest.
* antibiotics
- mycorrhizae: fungal symbiotes of certain plants.
The fungus increases the absorbance area of roots
dramatically, and passes water and nutrients to the plant.
The plant feeds the fungus with glucose.
- lichens – symbiote with alga
CRICOS Provider Code: 01505M
RTO Number: 3045
IV. Fungi
4. Ecological Roles
- decomposers: Fungi decompose liginin and cellulose,
which most free-living bacteria can’t digest.
* antibiotics
- mycorrhizae: fungal symbiotes of certain plants. The fungus
increases the absorbance area of roots dramatically, and
passes water and nutrients to the plant. The plant feeds the
fungus with glucose.
- lichens – symbiote with alga
- pathogens – Athlete’s foot, ringworm, yeast infections
- parasites – entomophagous fungi
CRICOS Provider Code: 01505M
RTO Number: 3045
Fungi are important in
nature
As decomposers
As pathogens of plants,
animals and humans, and in food
spoilage
As producers of secondary
metabolites, e. g. penicillin
In cheese, bread and wine
making
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RTO Number: 3045
CRICOS Provider Code: 01505M
RTO Number: 3045
Fly agaric
(flugsvamp)
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Ergot of rye
•Caused by Claviceps
purpurea.
•Cause of ergotism:
“Holy Fire” or “St.
Anthony’s Fire”.
•Sclerotia are
dangerous.
•Witch hunts.
•Caused low fertility
and death in 14th18th century Europe.
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RTO Number: 3045
Other toxins made by fungi
•Endophytic fungi (Acremonium) in
grasses can be toxic to cattle (fescue
toxicosis)
•Other mycotoxins:
• Ochratoxins
• Aflatoxins - carcinogenic
• Fumonosins - blind stagger of horses
• Patulin - bleeding in lungs and brain, kidney damage, cancer
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Medicines that come from fungi
•Penicillin. Penicillium chrysogenum.
Alexander Fleming, 1928.
•Cephalosporin
•Cyclosporin
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Fungal diseases of humans - mycoses
•Trichophyton rubrum. Causal agent of athlete’s
foot. Came from tropics.
•Candida albicans. Causes candidiasis = yeast
infections.
• Around genitalia.
• Disease of mouth and throat.
•Blastomycosis, Cryptococcosis,
Histoplasmosis, Aspergillosis are other
diseases.
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RTO Number: 3045
Smut infection of a wheat field in
Eastern Washington (1956)
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RTO Number: 3045
Ustilago maydis - the corn smut fungus
CRICOS Provider Code: 01505M
RTO Number: 3045
Ustilago maydis
is a popular food
delicacy in Mexico
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RTO Number: 3045
CRICOS Provider Code: 01505M
RTO Number: 3045
Examples of symptoms
caused by fungi:
Cankers
Storage rots of fruits and
vegetables
Rust, mildews
Leaf spots
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RTO Number: 3045
Pathogen life styles
Necrotrophs - kill
host cells with
Biotrophs toxins and
specialize on a
hydrolytic
living host.
enzymes.
Ex. Powdery
Ex: Botrytis
mildews and rusts.
cinerea.
Hemibiotrophs - start out
biotrophic. Then, they kill the
host cells. Ex. Phytophthora
infestans.
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RTO Number: 3045
Four phyla of fungi
oChytridiomycota - no sexual
spore
oZygomycota - zygospore
oAscomycota - ascospore
oBasidiomycota - basidiospore
CRICOS Provider Code: 01505M
RTO Number: 3045
Characteristics of fungi
Fungi have hyphae. A
mass of hyphae is a
mycelium. The hyphae
may be septate or
aseptate.
Specialized hyphae,
haustoria are feeding
structures.
CRICOS Provider Code: 01505M
RTO Number: 3045
Zygomycota
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IV. Fungi
B. Zygomycetes
- coenocytic hypha
- asexual reproduction
haploid hypha produces
sporangia and releases
spores.
CRICOS Provider Code: 01505M
RTO Number: 3045
IV. Fungi
B. Zygomycetes
- sexual reproduction
– hypha touch, and produce
gametangia. Gametes
produced inside – fusion
into dikaryotic cells (2
nuclei). Each dikaryon then
becomes diploid (fusion of
nuclei and undergoes
meiosis. Spores are
released.
- many are imporant
mycorrhyzal symbionts.
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RTO Number: 3045
Gametangia fuse to produce a zygospore (Rhizopus
stolonifer)
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RTO Number: 3045
Zygomycota
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RTO Number: 3045
IV. Fungi
C. Ascomycetes
- septate hypha
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IV. Fungi
C. Ascomycetes
- septate hypha
- characterized by
production of spore-bearing
“asci”
- baker’s yeast
(levening and fermentation)
- molds – pathogens of
plants such as Aspergillus,
Penicillium, Neurospora,
Chestnut Blight, Dutch Elm
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disease,
etc.
RTO
Number: 3045
IV. Fungi
C. Ascomycetes
- life cycle
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RTO Number: 3045
IV. Fungi
D. Basidiomycetes
- bear puffballs or
mushrooms as fruiting bodies
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RTO Number: 3045
IV. Fungi
D. Basidiomycetes
- bear puffballs or
mushrooms as fruiting bodies
- haploid hyphae fuse in
dikaryotic hyphae.
- these dikaryotic hyphae
form the fruiting structure.
CRICOS Provider Code: 01505M
RTO Number: 3045
IV. Fungi
D. Basidiomycetes
- bear puffballs or
mushrooms as fruiting bodies
- haploid hyphae fuse in
dikaryotic hyphae.
- these dikaryotic hyphae
form the fruiting structure.
- at the tip of each hyphae,
the basidium forms, in which
meiosis occurs to produce
new haploid spores.
CRICOS Provider Code: 01505M
RTO Number: 3045
- life cycle
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RTO Number: 3045
Ascomycota
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RTO Number: 3045
CRICOS Provider Code: 01505M
RTO Number: 3045
Penicillium and
Aspergillus
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RTO Number: 3045