Mycology - BIO 335, September 12, 2012
Zoosporic Fungi
Reading: Text chapters 1 and 2; Mushrooms Demystified pp. 4-22.
Objectives:
1) Know the lifestyles of Stramenopile Protists and Chytrid Fungi.
2) Consider how the combination of dispersal by both wind and water
(instead of just wind or just water) make them more dangerous
pathogens - and threats to biodiversity of plants and animals (e.g.
amphibians). How are these organisms changing human history?
http://en.wikipedia.org/wiki/Great_Famine_(Ireland)
http://www.historyplace.com/worldhistory/famine/index.html
Summary from Lecture 1 (last lecture)
•
Fungi are Eukarotes, they have absorptive nutrition, and their
cells are surrounded by cell walls, often composed of chitin
(Beta 1-4 N-acetylglucosamine).
• These features more or less distinguish fungi from other groups
of organisms.
• Fungal growth is vegetative (=somatic) or reproductive.
Vegetative growth is either unicellular (=yeasts) or filamentous.
Filamentous cells are called hyphae. Hyphae grow at their tips
and can branch to form many growing tips.
• A fungal colony (=a mycelium) growths radially (like the rays of
the sun or the spokes of a wheel) from the centre out. A circular
colony on a petri dish is a good example.
• Fungi reproduce mainly by spores.
Spores can be produced via
mitotic or meiotic nuclear divisions. A spore is a 1 to manycelled propagule (it germinates to form a new individual).
Fungi are eukaryotes:
Fungi are most closely related to animals:
There are four main groups of fungi (recognized as phyla or classes)
http://tolweb.org/Eukaryotes/3
You can determine what a name means by ending
and whether it is italicized:
Kingdom: EUMYCOTA
Phylum: Dikaryomycota
Subphylum: Basidiomycotina
Class: Holobasidiomycetes
Order: Agaricales
Family: Agaricaceae
Genus: Agaricus
Species: Agaricus brunnescens
-- the edible (supermarket) mushroom.
From your Text, “The Fifth Kingdom”
There are three main types of life cycles:
Mainly haploid
- zygotic meiosis
Mainly diploid
- gametic meiosis
Alternation of
multicellular haploid
and multicellular diploid
- sporic meiosis
Oomycota were thought to be fungi, but now are Protists,
in the groupings “Stramenopiles” or “Chromista”
Oogamy: sexual fertilization
Of large, female gamete by
Smaller male gamete.
Picture shows eggs in an
Oogonium.
Oomycetes are diploid. Most
fungi are haploid.
http://www.ucmp.berkeley.edu/chromista/oomycota.html
Oomycota were thought to be fungi, but now are Protists,
in the groupings “Stramenopiles” or “Chromista”
Key feature of Stramenopiles,different from fungi:
2 different flagella (whiplash + tinsel with mastigonemes).
Cell Walls contain cellulose, a polymer of Beta-(1->4) linked D glucose.
http://www.ucmp.berkeley.edu/chromista/oomycota.html
All Eukaryotic flagella share the same structure and function:
A chytrid fungus: Allomyces zoospore
(left) under the light microscope (phase
contrast; 1,000 x magnification).
The amazing thing about flagella is that
wherever we find them among eukaryotic
organisms, they have essentially the same fine
structure: along the shaft of the flagellum run 9
pairs of peripheral microtubules and 2 central
microtubules -- the 9 + 2 pattern. Each
microtubule is built from a protein called
tubulin, its subunits arranged in 13 vertical
stacks (count them in the picture below) around
a hollow centre. Images & text from “The Fifth
Kingdom.”
Oomycota: Saprolegnia is a typical
aquatic oomycete and is a fish
parasite.
Phytophthora infestans is a
terrestrial oomycete; it
caused the Irish Potato
Famine
http://eap.mcgill.ca/Publications/EAP73.htm#KNOW%20YOUR%20FUNGUS
Cabbagetown is a neighbourhood located on the east side of downtown
Toronto, Ontario, Canada. It comprises "the largest continuous area of
preserved Victorian housing in North America", according to the
Cabbagetown Preservation Association.
Cabbagetown's name derives from the Irish immigrants who moved to the
neighbourhood beginning in the late 1840s, said to have been so poor that
they grew cabbage in their front yards. Canadian writer Hugh Garner's
most famous novel, Cabbagetown, depicted life in the neighbourhood during
the Great Depression.
Much of the original Cabbagetown was razed in the late 1940s to make
room for the Regent Park housing project. The Cabbagetown name came to
be applied to the Victorian neighbourhood a few blocks to the north,
previously known as Don Vale. Corktown, to the south of Regent Park, dates
to the 1820s and now includes some of the original Cabbagetown.
http://en.wikipedia.org/wiki/Cabbagetown_(Toronto)
DISEASES: Sudden oak death, ramorum leaf blight, ramorum shoot blight
PATHOGEN: Phytophthora ramorum
HOSTS: More than 100 species of forest trees, native shrubs, herbaceous plants, and woody
ornamental plants
Phytophthora ramorum is a recently emerged pathogen with a host range of
more than 100 plant species. This protist causes sudden oak death on
certain members of the oak family, and has killed over 1 million trees in
coastal forests in California. The pathogen also causes ramorum leaf blight
or shoot blight on native plant species and horticultural nursery crops, and
has plagued some nurseries in California, Oregon, Washington, British
Columbia and in Europe.
In BC found on
Rhododendron in Nurseries:
http://www.agf.gov.bc.ca/cro
pprot/sod.htm
P. Ramorum and P. infestans have similar life cycles: ability of
sporangium to blow in wind or to produce multiple swimming
zoospores allows dispersal by air and water depending on
environmental conditions!
http://rapra.csl.gov.uk/images/lifecycle.gif
Fungi are eukaryotes:
Fungi are most closely related to animals:
There are four main groups of fungi (recognized as phyla or classes)
http://tolweb.org/Eukaryotes/3
Chytridiomycota are true fungi (chitin cell walls, etc.).
Their spores (zoospores) have one backward, whiplash flagellum.
Chytrids are found in a variety of moist habitats; some are parasites.
Synchytrium endobioticum causes wart disease of
potato.The pathogen is widespread in Europe, and
has spread to Newfoundland, but resistant
varieties of potato help to keep the disease under
control.
However, in Fall 2000, a small corner of one field
in Prince Edward Island, Canada, was found to be
affected by the disease. This brought an
immediate embargo on shipments from PEI to the
USA.
Chytrids parasitize algae
and dinoflagellates.
From your text, “The Fifth Kingdom.”
Tim James papers all available as PDFs at
http://www.umich.edu/~mycology/publications.html
Chytrid infection is causing loss of amphibian diversity worldwide -Humans have likely spread infection from an endemic source.
BD-Maps includes global surveillance data for
Batrachochytrium dendrobatidis.
Annual Review Microbiology 2009. vol. 63: 291-310. Excellent Review Paper.
Hotlinked from your BIO 335 Study Guide Above MAP is up-to-date (2012) from http://www.bdmaps.net/
Batrachochytrium uses
keratin as a nutrient
source, causing clinical
infections of adult
amphibian skin in and
nonclinical infections of
keratinized mouthparts
in juveniles.
The spherical sporangia
seen inside frog
epidermis (right) allow
diagnosis.
http://www.cdc.gov/ncidod/EID/vol5no6/daszak.htm
Mycology - BIO 335, September 12, 2012
Zoosporic Fungi
Reading: Text chapters 1 and 2; Mushrooms Demystified pp. 4-22.
Objectives:
1) Know the lifestyles of Stramenopile Protists and Chytrid Fungi.
2) Consider how the combination of dispersal by both wind and water (instead of just wind or just
water) make them more dangerous pathogens - and threats to biodiversity of plants and animals
(e.g. amphibians). How are these organisms changing human history?
,
http://en.wikipedia.org/wiki/Great_Famine_(Ireland)
http://www.historyplace.com/worldhistory/famine/index.html
Next Lecture: Zygomycota and Glomeromycota fuzzy bread and peaches, bbq tempeh, and the
origins of terrestrial plants….