Biology of Fungi - mycologysite.files.wordpress.com fileBIOL 319- Spring 2017 Fungi in the Tree of...
Transcript of Biology of Fungi - mycologysite.files.wordpress.com fileBIOL 319- Spring 2017 Fungi in the Tree of...
Lecture: What are Fungi? BIOL 319- Spring 2017
Biology of Fungi
What are Fungi? BIOL 319
Fungi in the Tree of Life (cont.)
Coincides with the rapid
expansion of multi-
cellular organisms Major multicellular
eukaryotes are divided
into Kingdoms Animals
Artistic vision of mushrooms among plants.
Plants Source: interactive.usc.edu/members/jchen/ Fungi
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Fungi in the Tree of Life (cont.)
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Fungi in the Tree of Life
Living organisms on
earth first arose about
3.5 billion years ago Prokaryotic Anaerobic
Oldest fossils of fungi are about 460 million years old
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Fungi in the Tree of Life (cont.)
Each of these three kingdoms differ in
their basic cellular structure and mode of
nutrition (defined by Whittaker, 1969) Plants - photosynthetic, cellulosic cell walls
Animals - digestive systems, wall-less cells
Fungi - absorptive nutrition, chitinous walls
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Fungi in the Tree of Life (cont.)
The estimates for the expansion of
multicellular organisms are based upon
phylogenetic analyses of Carl Woese Examined ribosomal RNA (rRNA)
Present in prokaryotes and eukaryotes Relatively stable, but changes occur over time;
thereby acting as a chronometer Distinguished three separate groups
(Domains) of living organisms BIOL 319
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ascospores (arrow) within the ascocarp. Source: www.ucmp.berkeley.edu/fungi/fungifr.html
Fossilized perithecium of what is believed to be a fungus of the genus Savoryella. Note the
Lecture: What are Fungi? BIOL 319- Spring 2017
Fungi in the Tree of Life (cont.)
Domains - rRNA sequence differences
correlate with differences in cellular
structure and physiology Bacteria - “true bacteria”
Archaea - “ancient prokaryotes”
Eucarya - eukaryotes Taxonomic grouping of “Kingdom” lies
beneath that of “Domain” BIOL 319
Fungi in the Tree of Life (cont.)
Though the fossil evidence suggests
fungi were present on earth about 450 million years ago, aquatic fungi (Phylum
Chytridiomycota) most likely were present about a million years before this
time About 354 - 417 million years ago, fungi
evolved with primitive land plants
BIOL 319 Defining the Fungal Kingdom
Mycology is the study of fungi
Myco- = fungi -ology = the study of
Mycology originally arose as a branch of
botany because fungi were once believed
to be “achlorophyllic” plants
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Figure 1.1, Deacon (2006) Fungal Biology, 4th ed.
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Fungi in the Tree of Life (cont.)
These plant-associated fungi probably
helped their photosynthetic partners
gather nutrients from the harsh soils of
the time These fungi were the early ancestors of
the present day phylum Glomeromycota Despite plant-fungus co-evolution, fungi
are more closely related to animals BIOL 319
Why Study the Fungi?
There are over 100,000 species of
known fungi and probably 15 times that
many that have yet to be discovered Fungi are an extremely important part of
the ecosystem Recycling of minerals and carbon
Cause plant and animal diseases Source of food, medicines, and chemicals
Important models in scientific research BIOL 319
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Lecture: What are Fungi? BIOL 319 - Spring 2017
A Brief History of Fungi
Greeks (about 300 B.C.)
believed truffles were
produced by thunder Oldest illustration of
fungi was found among the ruins of Pompeii
A truffle. Source: www.truffle-and-truffe.com (A.D. 79) that depicted
edible mushrooms BIOL 319
A Brief History of Fungi
Euripides (A.D. 450-456) recorded the
first mushroom poisoning deaths
Amanita muscaria, one of the most
poisonous mushrooms in the world.
Euripides. Source: uk.wikipedia.org Source: www.myco-vaud.ch
BIOL 319 Copyright © 2009 Chester R. Cooper, Jr A Brief History of Fungi (cont.)
A Brief History of Fungi (cont.)
During a period of the Middle Ages
(A.D. 1470 to 1670), books on ‘herbals’
were published that included illustrations
and descriptions of fungi Remarkably similar to those of Greeks
Used same methods to divide mushrooms
and truffles into poisonous and non-poisonous varieties
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Jerome Bock. Source: www.nndb.com
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The German herbalist Jerome
Bock wrote in A.D. 1552: “Fungi and truffles are neither herbs, nor roots, nor flowers, nor seeds, but merely the superfluous moisture of earth, of trees, or rotten wood, and of other rotting things. This is plain from the fact that all fungi and truffles, especially those that are used for eating, grow commonly in thundery and wet weather.” [From Ainsworth (1976) Introduction to the History of Mycology, as cited in
Moore-Landecker (1996) Fundamentals of the Fungi, 4th ed.]
A Brief History of Fungi (cont.)
Other cultures also believed the fungi
originated from thunder and lightning Hindu god Soma was a child of thunderstorms who offered hallucinogenic fluids from Amanita muscaria, one of the world’s most poisonous mushrooms
Similar legends existed in Guatemala and
Mexico BIOL 319
A Brief History of Fungi (cont.)
Modern times in the
study of fungi began with the invention of the microscope (about 1590-1600) by Hans and Zacharias Janssen of Holland
Zacharias Janssen. Source: www.astrophotoclub.com/history/telescope.htm
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Lecture: What are Fungi? BIOL 319 - Spring 2017
A Brief History of Fungi (cont.)
A Brief History of Fungi (cont.)
Robert Hooke used
the microscope to make the first drawings of a microscopic fungus (Mucor or Rhizopus) in 1665 and published them in his book Micrographia
Hooke’s drawing in Micrographia.
Source: www.unb.br/ib/cel/microbiologia
In 1699, fungi are found
to be a component of
lichens Anton van Leeuwenhoek
observes yeasts using a
microscope (1673)
British Soldier Lichen. Source: www.buenavistatownship.org
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BIOL 319 A Brief History of Fungi (cont.)
Hereafter, the study of fungi exploded with many different contributions over the next 300 years, including the one gene-one enzyme hypothesis (Beadle
and Tatum, 1941) and the Source: www.laskerfoundation.org 2001 Nobel Prize for cell
division studies in yeast BIOL 319
Defining the Fungal Kingdom
Fungi are simple,
eukaryotic microbes Many are microscopic Studies typically Macroscopic (above; from
Kendrick) and microscopic (below;
employ standard from Cooper) fungi
microbiological
techniques
BIOL 319 Copyright © 2009 Chester R. Cooper, Jr.
Defining the Fungal Kingdom (cont.)
Defining the Fungal Kingdom (cont.)
Mycologists (fungal
biologists) have
traditionally studied
not only the true
fungi (e.g., mildew),
but also fungus-like
organisms (e.g.,
slime molds)
Physarum polycephalum, a slime mold, growing out of
Petri dishes (upper image) and a closer view of the
plasmodium phase (lower image) Source:
waynesword.palomar.edu/slime1.htm
The kingdom Mycota
is comprised of the
true fungi True fungi have the
following features: Eukaryotic
Transmission electron micrograph of a fungal cell
showing typical eukaryotic structures. Source:
www.stchas.edu/faculty/zfitzgerald/fungi.jpg
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Lecture: What are Fungi? BIOL 319 – Spring 2017
Defining the Fungal Kingdom (cont.)
Fungal features (cont.):
Typically grow as
filaments, termed hyphae
(sing., hypha) via apical
growth [the latter differs
from the growth of other
filamentous organisms]
Scanning electron micrograph of a fungal hyphae growing on the surface of a leaf. Source: www.abdn.ac.uk/ims/h-em/images/sem4/pages/fungal-hyphae-on-leaf.html
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Defining the Fungal Kingdom (cont.)
Apical growth of a fungal hypha of Sclerotinia sclerotiorum.
Source: Fungal Cell Biology Group (www.fungalcell.org) BIOL 319
Defining the Fungal Kingdom (cont.)
Hyphal strand of a Streptomyces species. Note the newly dividing cell (arrow). Source: zoology.okstate.edu/zoo_lrc/biol1114/sample_tests/preview_material/exam1/s03/preview-exam1_s03.htm
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Defining the Fungal Kingdom (cont.)
Fungal features (cont.): Fungal hyphae
repeatedly branch to
form a network of
filaments termed a
mycelium (sing.,
mycelia) Drawing of a mycelium. Source: www8.nos.noaa.gov/
coris_glossary/index.aspx?letter=m BIOL 319
Defining the Fungal Kingdom (cont.) Fungal features (cont.):
Some fungi grow as a single-celled entity,
termed a yeast, that grows either by a
budding process or via binary fission
Budding yeast (left) and fission yeast (left). Sources: www.biochem.wisc.edu/yeastclub and
www.steve.gb.com/science/model_organisms.html BIOL 319
Defining the Fungal Kingdom (cont.)
Fungal features (cont.): Some fungi can switch growth
forms between a hyphal phase and a yeast phase, a property known as dimorphism
Typically induced by environmental
conditions A number of such fungi are disease-
causing agents of humans and
animals
Dimorphism of Candida albicans. Source: www.explorepub.com/articles/darkfield_charts/fungus9.html
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Lecture: What are Fungi? BIOL 319 - Spring 2017
Defining the Fungal Kingdom (cont.) Fungal features (cont.):
Heterotrophic (chemo-organotrophs) -
require preformed organic compounds Absorb nutrients after degradation by
exogenously released enzymes BIOL 319
Defining the Fungal Kingdom (cont.) Fungal features (cont.):
Unique cell wall components Chitin
Glucans Rare instances of cellulose, but definitely fungal cell walls are not as rich in this polymer as are plants
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Defining the Fungal Kingdom (cont.) Fungal features (cont.):
Typically have haploid nuclei Hyphae often have a number of haploid nuclei present in each cell
Some yeasts have a single diploid nucleus Reproduce both sexually and asexually,
typically through the production of spores BIOL 319 Defining the Fungal Kingdom (cont.) Fungal features (cont.):
Other differences [ Deacon, Table 1.1] between fungi and animals and plants include:
Histone types Sensitivity of microtubules to inhibitors
Manner of lysine biosynthesis Membrane sterols
Organellar structure/morphology
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Defining the Fungal Kingdom (cont.)
Asexual mitotically-derived spores (conidia; orange arrow in
above figure) of the fungus Scedosporium apiospermum and
the meiotically-derived spores (ascospores within a specialized
structure termed a cleistothecium; white arrow in figure to the
right) of the sexual form of the same organism given the
designation Pseudallescheria boydii
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Major Activities of Fungi Plant parasites
Irish potato blight of
the 1840s Dutch elm disease
Disappearance of
frogs in Costa Rica
Phytophthora infestans growing into the leaf of a potato plant (above) and the
resulting rotting tuber from infection by this fungus (right). Sources: www.seedquest.com/News/releases/2005/may/12297.htm and
www.science.siu.edu/plant-biology/PLB117/JPEG%20files/potato.blight.jpg
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Lecture: What are Fungi? BIOL 319 - Spring 2017
Major Activities of Fungi Plant symbionts
Lichens (can also
form with
cyanobacteria) Mycorrhiza
Mycorhizzal fungus associated with roots of a pine. Source: www.virtualmuseum.ca/Exhibitions/Mushroom/English/Species/mycorrhizal.html
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Major Activities of Fungi (cont.) Biological control agents
Mycoparasites (other fungi)
Entomopathogens (insects)
Nematophagous (nematodes)
Nematode trapping fungus. Source: Kendrick BIOL 319
Major Activities of Fungi (cont.) Toxin production (mycotoxins)
Aflatoxins (peanuts and grains)
Mushroom poisoning
Moldy corn due to the aflatoxin producer Aspergillus flavus. Source: www.ipm.iastate.edu/ipm/icm/2001/10-22-2001/earrot.html
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Major Activities of Fungi (cont.)
Human pathogens
About 200 known species of fungi are
known to infect humans Diverse diseases including:
Dandruff “ring worm”
Pneumocystis infection of HIV-infected persons
Candidiasis (Candida yeast) BIOL 319
Major Activities of Fungi (cont.) Decomposition
Cellulose (plant material)
Rumen fungi in cows Dry rot
Dry rot due to the fungus Serpula lacrymans.
Source: www.grzyby.pl/gatunki/Serpula_lacrymans.htm
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Fungi in Biotechnology Foods and flavorings
Edible mushrooms 5 million tons produced worth $14 billion (1994)
Diverse types now widely available in
supermarkets Alcoholic beverages
Breads, cheeses, soy sauce
Quorn mycoprotein BIOL 319
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Lecture: What are Fungi? BIOL 319 – Spring 2017
Fungi in Biotechnology (cont.)
Fungal metabolites
Two categories Primary - intermediates or end products of
common metabolic pathways essential for
normal cellular function Secondary - diverse range of compounds
formed by specific pathways of a given
organism and not essential for growth (but may
provide some selection advantage) BIOL 319
Fungi in Biotechnology (cont.) Fungal metabolites (cont.)
Examples of secondary metabolites β-lactam antibiotics, e.g., penicillins and
cephalosporins Non-β-lactam antibiotics, e.g., griseofulvin,
gliotoxin, ciclosporins Pullulan - film-wrap for food in Japan
Chitosan - sewage clarification, plant defense
initiator BIOL 319
Fungi in Biotechnology (cont.)
Fungal metabolites (cont.)
Examples of primary metabolites Citric acid (estimated 200,000 tons produced in
the year 2000) [soft drinks] Gluconic acid (estimated annual production of
100,000 tons) [food additive] Itaconic acid (estimated annual production of
80,000 tons) [paint and adhesive manufacture]
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Fungi in Biotechnology (cont.) Enzymes and enzymic conversions
Extracellular enzymes Commercially valuable roles
Food industry
Bioconversions Heterologous gene products -
expression of foreign proteins by fungi
having medical/industrial applications BIOL 319
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