Originally, the fungi were grouped with Kingdom Plantae. Recently, it has been shown that if anything, fungi are more closely related to animals than plants.
Kingdom Fungi is broken into 4 major phyla: Deuteromycota, Basidiomycota, Ascomycota, and Zygomycota. Chytridiomycota are sometimes included in this kingdom as a 5th phylum, and some molecular biologist group the Deuteromycota with their closest relatives in the other phyla rather than separating them into their own. According to current accepted theories, slime molds and water molds (Oomycota, Myxomycota, and Acrasiomycota are not phylogenetically related to the fungi, and therefore, they will not be covered here).
Deuteromycota These "fungi imperfecti" generally do not exhibit a sexual reproductive function. If they are found to do so, they are then grouped with their proper phylum.
Basidiomycota The "club fungi" include mushrooms, smuts, puffballs, shelf fungi, and many others. Beginning with the haploid spore, the life cycle starts by the spore germinating into a hypha, or long filament. The hypha divides and grows, and when it meets with another hypha, some of the cells in the hyphae will fuse by plasmogamy. The dikaryotic cells will continue to form hyphae, and at the tip, they will form basidiocarps, or fruiting bodies. Certain cells in the fruiting bodies can have their nuclei fuse (karyogamy) to make diploid cells, which can then go through meiosis to make 4 basidiospores. The spores are released, and the cycle repeats.
Ascomycota These "cup fungi" include the common molds and mildews that spoil food and attack plants, yeasts, truffles, and morels. An ascomycete Claviceps purpurea is also the cause of ergot, which is the source of lysergic acid diethylamide, everyone's favourite LSD. The life cycle of the ascomycete begins with the release of the haploid spore. The spore then germinates, forming a hypha. Several hyphae often come together, forming a mycelium. In this mycelium, many hyphae branch through asexual reproduction, but some of the hyphae may go through plasmogamy to become dikaryotic. The dikarya can then go through karyogamy to form a zygote, which then goes through meiosis to form between 2 and 8 ascospores encased in an ascus. The spores are released, and the cycle starts over. In the single-celled ascomycetes, such as the yeasts, the cycle is the same, save the formation of hyphae.
Zygomycota The zygomycetes include the common black bread mold Rhizopus. The life cycle of zygomycetes is simpler than the other fungi. The spore, once liberated, germinates and forms a mycelium of hyphae. Some of the hyphae can grow erect and form sporangia filled with haploid spores. This is its more common asexual reproductive stage. If conditions are adverse, and compatible opposite mating types are near each other, the hyphae will form gametangia. The gametangia fuse, forming a zygote, which immediate goes through meiosis to form four zygospores.
Chytridiomycota The chytrids are primitive, single-celled, colonial, or mycelial fungi that appear to reproduce asexually most of the time, only reproducing sexually in times of dire need.
Diseases caused by fungi
Some of the more well-known diseases caused by fungal infections include:
Fungi in Biochemistry and Molecular Biology
Several fungi are important as models for genetic and biochemical phenomena, including:
Fungi are one of the strangest of life's kingdoms. They are ubiquitous and very important to science and commerce. Fungi are responsible for everything from the creation of beer and cheese and life-saving pharmaceuticals such as penicillin. They are also the cause of deadly diseases like histoplasmosis and they can cause severe damage to crops and material goods.
Fungi may be more closely related to animals than plants. They are a taxonomical nightmare, however, because of their inherent variability. Along with this variability, which often entails multiple alleles for a single locus, other characteristics which make fungi special are:
From the BioTech Dictionary at http://biotech.icmb.utexas.edu/. Used with permission. For further information see the BioTech homenode.
Fungi are one of the five types of microbes1.
Fungi are plant-like organisms, but unlike plants they do not have chlorophyll. Because of this they cannot make their own food. Instead, fungi absorb food from dead organic matter. The function of fungus in the ecosystem is to break down complex organic substances and recycle carbon and other elements. Some fungi are biotrophic, meaning they feeding from living cells; others are necrotrophic, meaning they kill cells and then feed on them. Most fungi feed on plant material rather than animal material.
The main types of fungus are:
Some common fungal Diseases that affect humans are listed below.
The approximately 100,000 species of the Fungus kingdom are divided into four phyla, based on sexual characteristics.
The lichens (Mycophycophyta) were formerly considered to be a fifth fungus pyhla, but this is no longer true.
The visible part of a fungus is usually a "fruiting body" such as a mushroom. This is usually a small portion of the overall organism. The main body of most fungi is a web called the mycelium. The mycelium is made of very fine threads called hyphae. The hyphae branch and intertwine throughout the fungus' food source (such as soil or wood). A fungal mycelium is generally too fine to be seen by the naked eye, unless the hyphae are packed densely together.
The cell wall of a fungus is made of chitin, which is also found in insects. This is something that distinguishes fungi from plants - the cell walls of plants are made of cellulose.
Fungi are capable of two types of reproduction:
Each of the fungi phyla have a different form of sexual reproduction.
The types of diseases caused by fungi can be divided into 3 major categories:
The most well-known example of an allergic reaction to fungus is "toxic mould" and "sick building syndrome" in buildings. (This was in the news in April 2002. Celebrity Ed McMahon sued his insurance company over a botched repair that caused fungus to spread throughout his home, making his family ill and allegedly killing his dog, Muffin. On doctor's orders, the McMahons moved out of their six-bedroom home in September 2001. The suit was settled in May 2003 for $7.2 million US.) The resulting condition is Allergic fungal sinusitis which causes a variety of symptoms, and in extreme cases can result in anaphylactic shock. Note that while moulds are very common in buildings, and will grow anywhere that there is moisture, 'toxic' moulds such as Stachybotrys chartarum are very rare. More common indoor moulds include Penicillium (the basis for the drug Penicillin).
The most well-known examples of fungal toxins are toadstool poisoning. Toadstools such as the Death cap (Amanita phalloides) and Destroying angel (Amanita virosa, A. verna, A. bisporigera, A. ocreata) ultimately cause death due to kidney and liver failure. Another famous example is the Liberty Cap or Magic Mushroom ( Psilocybe semilanceata) which affects the central nervous system inducing a hallucinogenic response. Another example is ergotism, a syndrome which can cause gangrene, hallucinations, and death. It is caused by consumption of rye products contaminated with toxins produced by the mould Claviceps purpurea. This fungus' toxins may have caused illness and delirium in Salem, Mass. leading to the Salem witch trials!
Some fungal infections, called primary pathogens, can cause disease regardless of the previous health of the victim. Others, referred to as opportunistic, affect people with immune systems that are already weakened by other factors. Diseases caused by fungal infection include:
Fungi are the major cause of disease in plants, accounting for over 70% of major crop diseases. The Irish Potato Famine was caused by a fungus an oomycete*, Phytophthora infestans. (The distinction between fungus and oomycete is fairly recent.) Although P. infestans did not infect humans, humans were certainly affected by it!
* oomycete correction by cordyceps.
"FUN-gee". A two player game derived from John Horton Conway's "sprouts". All you need to play is a sheet of paper and one or two pencils/pens.
The name comes from an analogy of how some fungi ("FUN-guy") mate: by extending "tentacles" to meet each other and exchange genetic information.
Begin by drawing a horizontal line across the center of the paper, extending from one edge to the other. Agree on an even number of "diamonds" (usually 6 or 8), and draw half that number of diamonds on either side of the line. Place one less than that number of dots on the line itself. For example, for a game with 6 diamonds:
<> <> <> <----*----*----*----*----*----> <> <> <>
That's called a 6/5 game, for there are 6 diamonds and 5 dots. Note that if the number of dots is not exactly one less than the number of diamonds, it is a wildly unfair game. Leave a good amount of space between the line and the diamonds.
A valid move (for either player) is connecting two dots, considering diamonds as dots as well, with a line and then placing another dot somewhere along that line. "Line" here is used in a topological sense, in that it can curve and bend and twist (?), so long as it passes through no other lines. A dot may have no more than three lines emerging from it, considering a line passing through a dot as two emerging lines, one on either side. I know it seems very complicated, but it's quite simple; you just have to see it. Bear with me.
There are two players, the "offense" and the "defense". The goal of the offense is to interconnect all diamonds. So if the offense wins, you could start at any of the diamonds and run your finger down some series of line segments to get to any other diamond. The defense's goal is to stop this from happening. Offense goes first.
So, on the board above, a simple opening move could be:
<> <> <> \ * \ <---*---*---*---*---*---> <> <> <>
Don't forget to put the dot on your new line!
An example of a situation in which this game would be considered an offense win would be:
/------\ <> <>-*--<> | \ / *-------*---/ \ <---*---*---*---*---*---> \ / \------*-----/ | <> /<>| <> \--*---* / \--/
Admittedly, the defense played rather poorly in this game. A similar game in which the defense won would look something like:
/------\ <> <>-*--<> | \ / *-------*---/ \ <---*---*---*---*---*---> \ /*/ / \------*-----/ <> <> <>
Connecting that dot back into the line made it impossible for any of the three lower diamonds to connect in with the rest of the crowd. Thus, it's an offense lose.
Play a little with a friend or just experiment with it by yourself. At first it will seem like either the offense or the defense is greatly biased toward (for me, it seemed impossible to defend), but soon new strategies will emerge and you will see that it is, in fact, quite balanced.
Two defensive strategies to get you started:
And two offensive strategies:
One more tip: Start at a 2/1 game, and observe why that is an obvious defense win. Move to a 4/3 game, and analyze its strategy before going to the more challenging 6/5 and 8/7. I played on 20/19 once, and that wasn't too fun: too much to keep track of. But maybe I just don't understand its strategy yet :)
Happy gaming!
Fun"gi (?), n. pl. (Bot.)
See Fungus.
© Webster 1913
A group of thallophytic plants of low organization, destitute of chlorophyll, in which reproduction is mainly accomplished by means of asexual spores, which are produced in a great variety of ways, though sexual reproduction is known to occur in certain Phycomycetes, or so-called algal fungi.
⇒ The Fungi appear to have originated by degeneration from various algæ, losing their chlorophyll on assuming a parasitic or saprophytic life. By some they are divided into the subclasses Phycomycetes, the lower or algal fungi; the Mesomycetes, or intermediate fungi; and the Mycomycetes, or the higher fungi; by others into the Phycomycetes; the Ascomycetes, or sac-spore fungi; and the Basidiomycetes, or basidial-spore fungi.
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