Cordyceps

Awesome video about cordyceps right hurrrrrrr.

BIOL 3007 W: 17 Nov 2010

I took a nap in class today. It was amazing. We talked about ascomycota or something.

BIOL 3007W: 11/15/10

THis lecture is on the basal fungal groups: Chytrids, zygomycetes, and glomeromycota. None of them make large fruiting bodies.

chytrid: characterized by anchoring structures.
Zygo = yoke. zygospore is formed.
Arbusculus = small tree. (glomeromycota.)

basidio and ascomycota are the higher fungi. Chytrids appear to be polyphyletic, as do zygomycetes.

Chytrids: typically found in aquatic (freshwater) organisms. They occur as parasites on terrestrial organisms. They are the only fugi with motile cells in their life cycle (posterior, whiplash flagella = opisthokonta.) THey are mostly saprobic, and are important biodegraders. Some of them live in guts of herbivores as cellulose degraders (in which case they are obligate anaerobes. SOme are parasites on algae and other fungi (useful in case of feeding on algal blooms.)

Chytrid baits: chitin , cellulose (cellophane, wood), keratin (eg red hair), pollen grains (pine, spruce, oak) , seeds.
Thallus form: Monocentric thallus (one center with rhizoids.) Inside the host  they do not make rhizoids.  They make a sporangium (center of the picutre) anucleate rhizoids that anchor it. Papilla (where the zoospores emerge from.)

Life cycle of allomyces. allo=different. It is a tropical/subtropical fungus.  One of the best studies chytrids. Starting with the sporophyte: Fusion of two different size gametes. Starts growing by dichotomous branching. The branches have two kinds of sporangia on them. Resistant sporangia are brown. Germinate immediately to produce diploid zoospores. The resistant sporangia lie dormant for many months, so they are released under stress. They produce haploid gametophytes. The gametophytes will produce two kinds of gametangia (make and female.) The female gamete produces sirenin, which will cause male gametes to swim to the females. The AoG is isomorphic.

Chitridiomycosis: parasite of amphibians. (frogs) and has caused mass extinction. The cause is not certain. It attacks the skin of the frog, making the skin thick and inhbiting the ability of frogs to respire.

Zygomycetes: not a monophyletic group. Variable life styles: saprobic, arthropod guts, pathogens. fluffy white growth on bread and strawberries is prime example. They have both sexual and sexual reproduction. The mycelium is coenocytic.

Sexual reproduction involves a zygospore, whereas the asexual reproduction involves non-motile sporangiospores. Sporangia sitting on aerial mycelium. Sterile part = columella.

Mature: protogametangia (two cells that grow towards each other and then swell up.) they each cut off a cell at the tip, called suspensores. We see plasmogamy and karyogamy to produce the zygote, and the zygopore is like a yoke between the two cells,

Mucor: Sticky or slimy sporangia. Don’t get blown away. Insects or water disperse the sporangia.
rhizopus: dry spores. The wall breaks and the wind carries them away.
Thamnidium: Sporangium at the tip have sticky spores. The things down at the bottom are smaller sporangia which are dispersed by the wind.
coemansia: Sporangia have one spore. They are desert organisms. A droplet of water develops around it….
Cunninghamella: like thamidium, but also with 1 spore per sporangium.

Spirodactylon aureum. There ar a lot of spiraly things, which prevent the dispersal by air.
Entomophthora. Destroy flies and stuff. They parasitize flies and other insects. They are ballistospores, so they are shot away. They penetrate the exoskeleton
Pilobolus: Hat throw (the sporangia is the cap.) The sporangia can be shot for over 6 feet. They are adapted to be eaten by animals. They move according to the sun, and shoot at about 9 in the morning. Sticky stuff in the ring at the bottom of the spore.  Great video on pilobolus spore dispersal:

Life cycle of rhizopus: Asexual reproduction by sporangiospores. THey have two mating types (+ and -) There are compounds produced which diffiuse through the agar (and then through the air) to form the gametangia. The gametangia fuse to form the zygosporangium. When the zygosporangium germinates, it forms a sporangium (undergoing meiosis.) The mycelium is haploid, unlike in the oomyces.

Mating types: + and -. Takes two different thalli for mating (heterothallic)

Zygomycetes products: tempeh. Rhizopus oligosporus.

Glomeromycota: They make endomycorrhizae. Within a cell of a root, it looksl ike a root (arbuscule.) The fungus collapses without any obvious impact on the plant cell.

AM vs VAM: VAM: vesicle forms between the cells. It is storage structure that contains nutrients.  Herbaceous and woody plants usually make the arbuscular mycorrhizae.

Glomeromycota are obligate symbionts. They are difficult to grow in culture. They push in the plasma membrane, but the membrane remains intact. The arbuscule is short lived. They penetrate the cell wall, though. We don’t understand the life cycle at all.  They make large spores. Extension of the root system, aggregate the soil, glue together fine soil particles. They aid in phosphate and nitrogen uptake. Defense against parasites.

BIOL 3007W: 2010 Nov 8

Lab summary of stuff:

	Chlorophyta	Cryptophyta	Rhodophyta	Euglenophyta	Dinophyta	Haptophyta
Chloroplast	Primary endosymbiosis	Secondary endosymbiosis of red algae	Primary endosymbiosis	Secondary endosymbiosis of green algae	Secondary endo of red algae	Secondary endosymbiosis
Pigments	Chlorophyll a, b and carotenoids	Chlorophylls a, c and carotenoids	Chlorophyll a, phycobilins	Chlorophyll a, b and carotenoids	Chlorophyll a and c	Chlorophyll a and c
Supergroup	Archeplastida	Chromalveolata	Archeplastida	Excavate	Chromalveolata	Chromalveolata
Flagella	–	2 flagella, interior slightly unequal; apical tinseled	—	2: one emergent, one non-emergent	2: 1 extending	0 or 2 flagella
Storage molecule	starch	Pyrenoids ???	Floridean starch	Paramylon: starch like	Starch	chrysolaminarin

/* Humor
Prof: “How do red algae differ from green algae? It’s obvious! Red Algae are red and Green algae are green!”
Class: “LOL.”
*/

/* Not Humor:
Prof: “Final is on Dec 18: 4-6 PM.”
Class: “BOO.”
*/

Unilocular sporangia always pertain to meiosis, multilocular sporangia pertain to mitosis (preservation of ploidy.)

Resumption of lecture:

Kelps: Important economically. Harvested as though it is a lawn being mowed. Apical meristem: keep growing upwards. Extracted for algin. Mucilagenous cell wall material. Protects the thallus from buildup of organisms. Used as an emulsifier in food, paper coatings, paints, etc.

NEED TO KNOW: Kelp life cycle. Alternation of generations.

Starting in spring: fertilization occurs, zygote forms, zygote grows into typical sporophyte (holdfast, stipe, blade.) They grow all summer. They will undergo reproduction (meiosis)  by producing unilocular sporangia. They will produce two motile cells to produce the male and female gametophyte stages. The male gametophyte appears more hairy?

Alternation of generations is obligatory: selection for sexual reproduction. There is no asexual phase of the life cycle.

/* TECHNICAL PROBLEMS. FORGOT TO PLUG IN INTERNET.*/

Video resumed. Some information on kelp and various ecological roles of kelp can be found on this website. I believe this is the video being shown in class. Very well made.

Stramenophiles: Moving on: Oomycetes, then progress to slime molds.

Xanthophyta: mainly freshwater. “Yellow-green algae.” They are stramenophiles that lack green algae. They mimic the green algae. They have chlorophylls a and b, they have typical motile cells, storage products are not starch based (differentiate them from green algae.)

We will be looking at Vaucheria. Similarity to the oomycetes (morphological:) oogonium fertilized by male gametes from the coiled antheridium.  Relatively easy organism to find.

Oomycota: the “egg” give the fungi their name. Resting stage is called the oospore. Oogamy: egg is much larger than the male gamete. THERE IS NO MOTILE MALE GAMETE IN THE OOMYCETES.

Similarities to the true fungi: heterotrophic nutrition, and acquire nutrients by extracellular degradation. secretion of enzymes to digest substrate followed by absorption of substrate.

Why are oomycota not true fungi? Zoopores with whiplash and tinsel, cellulose and beta glucan in cell walls.

Phytophthora: plant destroyer. caused irish potato famine. Originated in South America, crossed over the Atlantic. Late blight of potatoes and tomatoes. Sporangia disperse. The zoospores are the only motile cells in the life cycle and require water. Derives nutrition initially from living plant tiuuse, then from dead tissue.

The Bordeaux mixture: lime and copper sulfate, used as the first fungicide. Last summer, there was a major outbreak of p. infestans. Another species: p. ramorum. Oaks are susceptible. Brown stuff exuding from the bark is evident in infected plants. Nurseries spread it around.

Genomes of phytophthora: 3 have been sequenced. One is from P. infestans. – 2.5-4 times the other two. one of the other organisms is p. ramorum. Problem: It can change very rapidly. Most of the expansion is non-coding. The disease-causing genese are in the expansion region, and are increasing in copy number.  http://www.nature.com/nature/journal/v461/n7262/full/nature08358.html

Oomycota: Water molds: Did stuff in lab today with putting fly in lake water. Need to keep it dilute. Terrestrial group are the plant pathogens.

Watermolds are abundant in freshwater. Theyir nutrition is mostly saprophytic or parasitic. They reproduce sexually and asexually.  The vegetative state is a coenocytic filament. They have sexual and asexual phases. Transition triggered by deterioration in the environment. The antheridia grow to the oogonia.  Life cycle can be found here. NEED TO KNOW LIFE CYCLE.

White rust: Albugo. We get a white powder on the surface. They are obligate parasites. Can’t grow them in culture. They attack species in the cabbage families. Infects the leaves, grows inside the leaves. Makes chains of sporangia (sporangiophore) which pop out on the surface. The spores are distributed by wind. If conditions are good, they’ll make the zoospore to infect host.

11/03/2010 BIOL 3007 Lecture

Short blurb on coral bleaching.

Stramenophiles aka heterokonts (kont = flagellum.) Common theme: two flagella. One is tinseled, the other is whiplashed. Stramenophiles: straw, hairs. Hairs are tripartite.

They include the golden algae, the brown algae, the diatoms, and oomycota (a fungal group.)

/*this prof really loves the etymology of names, eh*/

Golden algae: chrysophyta. They like unpolluted waters. Mostly cold, freshwater dwelling.  Active during the winter. Won’t survive in warm conditions. They can cause toxic blooms. Can also influence the quality of water. They may be unicellular or colonial. Sitting in a cuplike protective structure: Similar to tricholomonas.

All stramenophiles have the same kind of pigments: chlorophylls a and c, as well as fucoxanthin. The fucoxanthin gives them a yellow colour. golden algae produce chrysolaminarin. They may have scales with silica or walls with cellulose.

Tinsel flagellum is longer than the whiplash flagellum. They have 3 types of hair: thin hair at the top, stouter hair in the middle which connects to a thicker hair at the bottom. The scales have silica.

They also produce cysts in the resting state. Cysts can be produced by asexual or sexual reproduction. THey begin to deposit the silica inside the cytoplasm. They make a bottle, and sit in the bottle. They make a plug, and unplug the bottle during germination.

DIATOMS:

Important components of phytoplankton. THey are both marine and freshwater organisms. THey are major contributors to photosynthesis. ~25% of global carbon is fixed  by diatoms. Important food source of many marine organisms. Their walls have silica and pectin (very distinctive.)

Colonial diatoms, can literally be unfolded or aggregate into starlike shapes. Many are single celled. Some are radially symmetric (Centric diatoms: mostly floating and planktonic), and others are bilaterally symmetric (mostly bottom dwelling on vegetation; little groove that runs through the shell to enable gliding motility.) The surfaces have all sorts of ribbing and sieve like components.

FRUSTULE: ONE PIECE BIGGER THAN THE OTHER. Overlapping halves. Asexual reproduction by mitosis. Formation of a membrane that lies between the two nuclei, made of silica. Makes two new BOTTOMS. They’d have to become smaller and smaller if they kept dividing that way…

/* I wonder if that’s gonna be on the test */

Gametic meiosis . Very large zygote called the auxospore is formed. Divides tor produce some very large cells, then goes through a cascade of shrinking down.

Perforation: solid glass wall would make them sink. Perforation helps them be lighter. Also promotes water and nutrient exchange. http://onlinelibrary.wiley.com/doi/10.1002/adfm.200700609/abstract

Diatomaceous earth: used to make filtered liquids, production of antibiotics, insulation, etc. Also yields geological information of  lakes and oceans. Slide on “Rock Snot“

Brown algae: last group. They do not have any unicellular or multicellular forms. They are usually filamentous (morphologically complex thalli.) Diverse life histories. Grow best in cold water.

The storage products are a little different (laminarin instead of chrysolaminarin.) Ectocarpus is a simple brown alga. Alternation of generations (isomorphic.) They have different types of sporangia. Unilocular in which meiosis occurs to make haploid zoospores (germinate to make gametophytes) and plurilocular which has many chambers, and makes diploid asexual zoospores (motile.)

Fucus, conceptacles. diploid life cycle.