Fungi are ..whether you encounter in our know it or not ... in our everyday lives....whether you know it or not! Very diverse group of organisms Tremella mesenterica(Witches Butter)

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Fungi are Fungi are organisms that we organisms that we encounter in our encounter in our everyday lives..everyday lives..

..whether you ..whether you know it or not!know it or not!

Very diverse Very diverse group of group of organismsorganisms

Tremella mesenterica (Witches Butter)

Athlete’s Foot Metatrichia vesparium (Slimemold)

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Ring Worm Peltiger venosa

Geastrum tripex (Earthstar) Various cultivated mushrooms

Roquefort or Blue Cheese Camembert or Brie

Cheese

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Leavened and Unleavened BreadSoy Products

Rhizopus stolonifer (Zygospore) Alcoholic Beverages

Aseroe rubra (Stinkhorn)

ButWhat is a Fungus?

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A very diverse group of

organisms..

..genetically and in

appearance

What is a fungus?

What is a Fungus?1.Alexopolous (1952)

"nucleated, achlorophyllous organisms which typically reproduce sexually and asexually, and whose usually filamentous branched somatic structures are surrounded by cell walls"Excluded slime molds!

What is a Fungus?2.Alexopolous (1962)

"nucleated, achlorophyllous organisms which typically reproduce sexually and asexually, and whose usually filamentous branched somatic structures are surrounded by cell walls"composed of cellulose or chitin or bothIncluded slime molds!

What is a Fungus?3.Currently, in the sense of

most mycologists??? organisms that are nucleated, achlorophyllous, typically reproduce sexually and asexually by sporesspores, and whose somatic structure is composed of filamentous branched or yeastyeast, which are surrounded by cells walls composed of chitinchitinExcludes slime molds and others!

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Characteristics of Fungi1.Heterotrophs

a.Heterotroph categories:i.Saprobesii.Parasitesiii.FacultativeFacultative saprobes and

parasitesiv.Symbionts (mutulalistic)

Characteristics of Fungi

2.Fungus bodybody

b.Yeast

a.Hypha (pl.=Hyphae)Mycelium (pl.=Mycelia)


Mycelium forming circular colony from radial growth (left) and mycelium as observed with microscope (right)


2.Fungus bodybodya.Hypha (pl.=Hyphae)

Mycelium (pl.=Mycelia)i.Coenocyticii.Septate

Coenocytic Coenocytic HyphaHypha

MyceliumMycelium

Septate HyphaSeptate HyphaSeptum Septum (pl.=septa)(pl.=septa)

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Characteristics of Fungi2.Fungus bodybody

b.Yeast: unicellular, asexual reproduction, budding or fission.

c.Dimorphic: Having a yeast and mycelium phase in the same fungus. RhodotorulaRhodotorula:

YeastTremella

mesenterica:Dimorphic

YeastYeast

MyceliumMycelium

Budding YeastBudding Yeast

3.Reproduce by sporessporesa.Variable in size, shape and

color. Sexual or asexual.

Spores are often borne directly on modified hyphae

Penicillium notatum colony and conidia and conidiophore (asexual)

Spores are not always borne directly on mycelium.

Fruitbodies, e.g. mushrooms formed from mycelium produce spores (sexual).

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Fruiting Bodies can be of Fruiting Bodies can be of various shapes, sizes and colorvarious shapes, sizes and color

All are composed of tightly interwoven mycelium.

Characteristics of Fungi4.Presence of cell wall: ChitinChitin

5.Eukaryotes: Membrane bound organelles, e.g. nuclei, mitochondria, plasma membrane, etc.

and infrequently celluloseand infrequently cellulose

Characteristics of Fungi6.Mode of nutrition: Absorption

a. Fungi “live” in their food.b. Digestive enzyme(s) released to

act on InsolubleInsoluble food.c. Break-down (digestion) of food.d. Fungi “absorbabsorb” (=eat) digested

food.e. Only sequence of events differ

from animal ingestion of food.

Characteristics of Fungi6.Mode of nutrition: Absorption

f. If food is solublesoluble, e.g., composed of simple molecules such as sugars and amino acids, digestive enzymes are not necessary.

g. Soluble food can be directly absorbed into cells.

Summary of AbsorptionAbsorptionSexual vs. Asexual

Reproduction1.Sexual Reproduction

a. Two parents required.b. Children borne will all be

genetically unique.c. Children will inherit

characteristics from bothparents.

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Sexual vs. Asexual Reproduction

2.Asexual Reproductiona. Only one parent is involved.b. Children borne will all be

genetically identical to parent.

Post Scripts

Fairy ring is about 25 ft. in diameter

World’s largest fairy rings:

Mushroom Armillaria gallica reported on April 2,1992

1.Mycelium (rhizomorphrhizomorph) of mushroom covered 37 acres

2.Over 1500 years old.


Mushroom Armillaria ostoyae reported on May 18,1992

1.Rhizomorphs of mushroom covered 1500 acres

2.Age???


Mushroom Armillaria ostoyae.1.Rhizomorph of mushroom

covered 2,200 acres

2.Over 2400 years old.

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Misconceptions About Fungi

1.Temperature: Fungi grow best at warm temperaturesa. Probably most grow better

at 70-90°F., But…b. Some can thrive at

temperatures of 130-150°F.c. Some can thrive at temperatures

below 32°F (below freezing).


2.Water: Fungi need lots of water.a. Again, mostly true. But…b. Some can grow in very dry

conditions, e.g. contaminate grains and dried fruits.

c. Some can grow underwater.


3.Light: Fungi grow best in the dark.a. Light is usually not important

in growth of fungib. Some species do have a light

requirement for reproduction, but not for growth.

Summary of Characteristics

5.Eukaryotes

2.Body composed of hypha-mycelium or yeast, or both.

3.Reproduce by spores

4.Cell Wall, usually of chitin, rarely cellulose.

1.Heterotrophs.

6.Mode of nutrition, absorption

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Fungi are ..whether you encounter in our know it or not ... in our everyday lives....whether you know it or not! Very diverse group of organisms Tremella mesenterica(Witches Butter)