Transcript Mycology

Kingdom: Fungi
Five kingdom system of classifying living things showing that both fungi and animals may have
evolved from a common ancestor
Mycology
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Mycology is the study of fungi which includes yeast and
molds
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They are eukaryotic and are chemo-heterotrophs (require
organic compounds for energy and a carbon source)
Most have a cell wall of chitin
Molds are made of long filaments called hyphae
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Fungi
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Chitin cell walls
Use organic chemicals for
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multicellular consisting of
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composed of filaments called
hyphae.
Yeasts are unicellular.
Figure 1.1b
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Fungi are important as
pathogens of animals
and plants.
 Over 70% of all plant
diseases are caused by
fungi
Mycelium are of three kinds:
1- vegetative mycelium ( penetrates the surface of the
medium and absors nutrients
2- Aerial mycelium ( grow above the agar surface)
3- Fertile mycelium (bear reproductive structure such as
conidia or sporangia)
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Yeasts are non-filamentous, unicellular fungi that are
oval or spherical in shape.
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Yeasts reproduce by the process of budding or binary
fission.
Candida albicans
Classification Fungi based on there sexual
reproduction :
Zygomycetes: zygospores, ex. Mucor & Rhizopus
Mucor
Rhizopus
Mycology
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Fungi are classified based on the type of
sexual spore that they form
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Zygomycota
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Have non-septate hyphea
Have asexual sporangiospores
Form sexual zygospores. They are large spores
enclosed in a thick wall and formed from the fusion
of two cells
Zygospores
Ascomycetes : Ascospores, ex:
saccharomyces, Aspergillus & Penicillium
Yeast
Aspergillus
Penicillium
Mycology
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Ascomycota
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Have septate hyphae
Have asexual conidiospores
Have sexual ascospores. Ascospores result
from the fusion of nuclei of two cells. They
are produced in a sac-like structure called an
ascus.
Ascospores inside an ascus
Basidiomycetes: Basidiospores, ex.: Rust
fungi & Mushroom.
Rust fungi
Mushroom
Mycology
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Basidiomycota
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Have septate hyphae
Have asexual conidiospores
Have sexual basidiospores. Basidiospores are
formed externally on a base pedestal called a
basidium
Basidiospores
Deuteromycetes: not produce any
sexual spores, ex.: Monilia fungi &
Botrytis
Monilia fungi
Botrytis
Classification Fungi based on morphology:
Moulds (Molds): Filamentous fungi Eg. Aspergillus
Yeast : Eg. Saccharomyces
Yeast like: Similar to yeasts but produce psedohypha
Eg. candida albicans
Dimorphic: Two different morphological form at two
different enivormental conditions
Mycology
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Dimorphic fungi
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Some fungi, including most of the pathogenic fungi,
exhibit two forms of growth. This is known as
dimorphism and the organisms can grow either as a yeastlike form or a mold-like form.
Frequently the form that the organism grows as is
temperature dependent and at 370 C the organism grows
as a yeast-like form and at RT or at 250 C it grows in a
mold-like form. CO2 concentration or the presence of
serum may also be a determining factor
Classification Fungi according
to nutrion:
Saprophytic
Parasitic
Symbiotic or Mycorrhizal
How do Fungi get their
Nutrition?
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Heterotrophs
fungal cells
secrete digestive enzymes
 absorb digested material
into cell
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predators
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decomposer
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Laboratory identification fungi:
Specimen collection: soil, moldy food,
plants, water, air,……etc.
Microscopy: Lactophenol cotton blue
Culture : Potato Dextrose Agar (PDA)
Classification Fungi based on hypha:
Septate – Non septate
Somatic hyphae .A) Portion of a hypha having more than one
nucleus (nonseptate);
B) Portion of a septate hypha.
Cross Walls of Hyphae
Coenocytic hyphae where the
nucleis of each cell is
embedded in the cytoplasm
without a cell wall
Eg. Zygomycota, Oomycota
Hyphae with cross walls
Eg. Basidiomycota,
Ascomycota