Presentation on theme: "Characteristics of Kingdom Fungi The Kingdom Fungi includes very important organisms, both in terms of their ecological and economic roles."— Presentation transcript:
Characteristics of Kingdom Fungi The Kingdom Fungi includes very important organisms, both in terms of their ecological and economic roles.
How are fungi “Helpful”? By breaking down dead organic material, they continue the cycle of nutrients in ecosystems. Most plants could not grow without the symbiotic fungi, or mycorrhizae, that inhabit their roots. Fungi provide drugs (such as penicillin and other antibiotics), We eat foods like mushrooms, truffles & morels, they make bubbles in bread, champagne, and beer. A number of fungi, in particular the yeasts, are important " model organisms" for studying problems in genetics and molecular biology.
Ways Fungi are Harmful: Fungi cause a number of plant and animal diseases: in humans, ringworm, athlete's foot, and several more serious diseases are caused by fungi. Because fungi are more chemically and genetically similar to animals than other organisms, this makes fungal diseases very difficult to treat. Plant diseases caused by fungi include rusts, smuts, and leaf, root, and stem rots, and may cause severe damage to crops.
Originally classified as plants- Fungi are not plants, because they are heterotrophs Fungi are more closely related to animals than to plants. BUT- Unlike animals, they absorb their food rather than ingest it, They have cell walls. For these reasons, these organisms are now placed in their own kingdom, Fungi.
The Mushroom Some people associate fungi with the mushroom. When you think of a “mushroom” – you are actually looking at the fruiting body of Basidiomycota (We will look at several phylum) Image from wilipedia Amanita muscaria, commonly known as the fly agaric or fly Amanita, is a poisonous and psychoactive basidiomycete fungus, one of many in the genus Amanita.
C. Fungi Structures Hyphae -A hypha (plural hyphae) is a long, branching filamentous cell of a fungus Mycelium - is the vegetative part (The “body”of a fungus), consisting of a mass of branching, thread-like hyphae Basidiocarp - is the spore-producing part of a fungus (- the fruiting part or commonly known as the mushroom) Cell walls – made of chitin.
Like plants and animals, fungi are eukaryotic multicellular organisms Unlike these other groups, however, fungi are composed of filaments called hyphae their cells are long and thread-like and connected end-to- end, as you can see in the picture.
Describing Hyphae can be septate (individual cells divided by cells walls) or coenocytic (joined together- not separate cells). Because of this diffuse association of their cells, the body of the organism is given the special name mycelium, a term which is applied to the whole body of any fungus
Reproductive Hyphae form a large organized structure called a basidiocarp, or mushroom. This is produced solely for the release of spores, and is not the living, growing portion of the fungus.
The fungal cell wall: Chitin is a nitrogen-containing polysaccharide present in the cell walls of many fungi. Notice this is a different polysaccharide than the cellulose that makes up plant cell walls. Chitin is the same material that makes up the exoskeleton of insects and other arthropods like crabs & lobster.
Selected Phylums we’ll discuss: (Note: Some biologists refer to fungi phylum as divisions.) 1. Phylum Zygomycota- example- Bread fungus – Rhizopus stolonifer Black bread mold is the best known of this phylum of around 600 species. Zygomycota are terrestrial organisms -can be found in richly organic soils.
2. Phylum Basidiomycota example- button mushroom - Agaricus sp. Basidiomycota are often called club fungi because they produce small clublike reproductive structures called basidia (what you call the mushroom ). Many “mushrooms” in this phylum look like umbrellas growing from the ground or like shelves growing on wood, but some, such as the latticed stinkhorn, can look quite different.
Remember- A “mushroom” is the above-ground fruiting body (that is, a spore- producing reproductive structure) of a fungus, having a shaft and a cap. –The rest of the fungus- its mycelium- is usually hidden under bark, ground, rotted wood, leaves, etc. –The technical term for the spore-producing structure of "true" mushrooms is the basidiocarp. –The term " toadstool" is used typically to designate a basidiocarp that is poisonous to eat
Among the more famous families in phylum Basidiomycota are: Agaricus -- including the supermarket variety of button mushrooms Amanita -- including species that are deadly, delicious, or even hallucinogenic; including the delicious and beautiful –Chanterelle, one of the most prized wild mushrooms. These families include but a few of the mushrooms sought by collectors & gourmets from among the 25,000 species in this phylum.
Agaricus sp. a spore print- made by leaving a mushroom cap overnight on a piece of paper
3. Phylum Ascomycota example – yeast –Candida species There are many types of Ascomycota, including what are called sac-fungi that form ascocarp reproductive features. The most commonly known Ascomycota are”yeasts” like brewers & baker’s yeast (Saccharomyces visiae) and Candida sp.- the yeast that are parasitic to humans & other organisms.
Yeast infections are a very common cause of disease and discomfort. Most cases of yeast infection in the United States are caused by Candida albicans. "Yeast" is the term for a fungus that exists as a single-celled organism rather than as hyphae. There are about 500 species of yeasts in 60 genera, or about 1000 species of yeasts or yeast-like organisms. Some fungi are called yeast-like because they exist as a yeast for part of their life cycle, but can be hyphal for a significant portion of it.
Budding yeast The photo shows 2 yeast cells. The right one is “budding”- one form of reproduction. The term "yeast" is of no taxonomic significance. It is useful only to describe a morphological form of a fungus.
4. Lichens & Mycorrhizae These are symbiotic relationships between a fungus & another organism. The result is a new organism distinctly different from its component species. Though no longer considered a proper phylum, the radically different nature of these symbiots warrants separate treatment in this overview of the fungus kingdom. Mycorrhizae are symbiotic associations between a fungus & plant roots. They help each other- the fungi provide phosphates & nutrients for the plant & the plant provides sugar made from photosynthesis to the fungi.
Lichens are symbiotic relationships between a fungus (usually ascomycetes) & an algae or cyanobacteria. The fungus provides shelter & an anchor to rocks, bark while the algae or bacteria provides sugar. Lichens are important pioneer species, and while widespread through different ecosystems- can live in harsh environments like the tundra or on barren rock like on new volcanic islands. `
E. A warning about poisonous mushrooms: Unless you are absolutely certain about the identification of a mushroom, do not eat it! (no eating mushrooms found on hiking trails) NO MUSHROOMS ARE POISONOUS TO THE TOUCH HOWEVER EATING A POISONOUS MUSHROOM WILL MAKE YOU SICK & SOME SPECIES ARE LETHAL.
Galerina autumnalis The a-amanitin ultimately affects the central nervous system and kidneys. Unlike many fungal toxins it does not cause symptoms right away. As long as 6-24 hours after ingestion there may be an early feeling of unease, followed by violent cramps and diarrhea. On the third day, there is a remission of symptoms,but this is a false remission. On the 4th to 5th day the enzymes increase, and liver and kidneys are severely affected. Death often follows if a liver transplant or other heroic measures are not performed. There is no cure for ingestion of the poison once it gets this far, but doctors are getting much better at treating the symptoms. This is *not* a mushroom you want to mess around with. botit.botany.wisc.edu/toms_fungi/may2003.html From: Tom Volk's Fungus
Death Cap (Amanita phalloides) NO MUSHROOM is worthier of fear. This single, widespread species of mushroom is solely responsible for the majority of fatal and otherwise serious mushroom poisoning cases, worldwide as well as in North America. Indeed, one might argue that the Death Cap's notorious, relatively frequent victimization of Homo sapiens is far and away the best explanation (or rationalization) for the widespread fear of edible wild mushrooms.
Amanita verna & Amanita virosa (the destroying angel). Death takes place within 6-8 days due to liver and renal failure & cardiac damage.
Historical Note: Claviceps purpurea- funus that infects seeds of grains (like wheat, rye,etc) Common name is Ergot Chemicals that it produces, when eaten, can cause mental disturbances, convulsions, perceptual distortions. Disease is called erotism or “St. Anthony’s Fire” Scientists now think that many women accused of being witches during the 1692 Salem witch trials may have had this disease.
II. Humans & Fungi
References (in addition to those noted on slides) htmlhttp://botit.botany.wisc.edu/toms_fungi/jan99. html HOLT Biology textbook