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Mycelium

Mycelium

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Mycelium (plural mycelia) is the vegetative
Vegetative reproduction
Vegetative reproduction is a form of asexual reproduction in plants. It is a process by which new individuals arise without production of seeds or spores...

 part of a fungus
Fungus
A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds , as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from plants, animals, and bacteria...

, consisting of a mass of branching, thread-like hypha
Hypha
A hypha is a long, branching filamentous structure of a fungus, and also of unrelated Actinobacteria. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium; yeasts are unicellular fungi that do not grow as hyphae.-Structure:A hypha consists of one or...

e. The mass of hyphae is sometimes called shiro, especially within the fairy ring fungi. Fungal colonies composed of mycelia are found in soil and on or within many other substrates. A typical single spore
Spore
In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoa. According to scientist Dr...

 germinates into a homokaryotic
Homokaryotic
Homokaryotic refers to multinucleate cells where all nuclei are genetically identical. It is the antonym of heterokaryotic....

 mycelium, which cannot reproduce sexually; when two compatible homokaryotic mycelia join and form a dikaryotic mycelium, that mycelium may form fruiting bodies
Sporocarp (fungi)
In fungi, the sporocarp is a multicellular structure on which spore-producing structures, such as basidia or asci, are borne...

 such as mushroom
Mushroom
A mushroom is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground on soil or on its food source. The standard for the name "mushroom" is the cultivated white button mushroom, Agaricus bisporus; hence the word "mushroom" is most often applied to those fungi that...

s. A mycelium may be minute, forming a colony that is too small to see, or it may be extensive:
It is through the mycelium that a fungus absorbs nutrient
Nutrient
A nutrient is a chemical that an organism needs to live and grow or a substance used in an organism's metabolism which must be taken in from its environment. They are used to build and repair tissues, regulate body processes and are converted to and used as energy...

s from its environment. It does this in a two-stage process. First, the hyphae secrete enzyme
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...

s onto or into the food source, which break down biological polymers into smaller units such as monomers. These monomers are then absorbed into the mycelium by facilitated diffusion
Facilitated diffusion
..Facilitated diffusion is a process of passive transport, facilitated by integral proteins. Facilitated diffusion is the spontaneous passage of molecules or ions across a biological membrane passing through specific transmembrane integral proteins...

 and active transport
Active transport
Active transport is the movement of a substance against its concentration gradient . In all cells, this is usually concerned with accumulating high concentrations of molecules that the cell needs, such as ions, glucose, and amino acids. If the process uses chemical energy, such as from adenosine...

.

Mycelium is vital in terrestrial and aquatic ecosystem
Ecosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....

s for its role in the decomposition
Decomposition
Decomposition is the process by which organic material is broken down into simpler forms of matter. The process is essential for recycling the finite matter that occupies physical space in the biome. Bodies of living organisms begin to decompose shortly after death...

 of plant material. It contributes to the organic fraction of soil, and its growth releases carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...

 back into the atmosphere. The mycelium of mycorrhiza
Mycorrhiza
A mycorrhiza is a symbiotic association between a fungus and the roots of a vascular plant....

l fungi increases the efficiency of water and nutrient absorption of most plants and confers resistance to some plant pathogens. Mycelium is an important food source for many soil invertebrates.

Sclerotia are compact or hard masses of mycelium.

Uses


One of the primary roles of fungi in an ecosystem is to decompose
Decomposition
Decomposition is the process by which organic material is broken down into simpler forms of matter. The process is essential for recycling the finite matter that occupies physical space in the biome. Bodies of living organisms begin to decompose shortly after death...

 organic compounds. Petroleum
Petroleum
Petroleum or crude oil is a naturally occurring, flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights and other liquid organic compounds, that are found in geologic formations beneath the Earth's surface. Petroleum is recovered mostly through oil drilling...

 products and pesticide
Pesticide
Pesticides are substances or mixture of substances intended for preventing, destroying, repelling or mitigating any pest.A pesticide may be a chemical unicycle, biological agent , antimicrobial, disinfectant or device used against any pest...

s that can be contaminants of soil are organic molecules. Therefore, fungi should have potential to remove such pollutant
Pollutant
A pollutant is a waste material that pollutes air, water or soil, and is the cause of pollution.Three factors determine the severity of a pollutant: its chemical nature, its concentration and its persistence. Some pollutants are biodegradable and therefore will not persist in the environment in the...

s from the soil environment, a process known as bioremediation
Mycoremediation
Mycoremediation, a phrase coined by Paul Stamets, is a form of bioremediation, the process of using fungi to degrade or sequester contaminants in the environment. Stimulating microbial and enzyme activity, mycelium reduces toxins in-situ...

.

Mycelial mats have been suggested (see Paul Stamets
Paul Stamets
Paul E. Stamets is an American mycologist, author, and advocate of bioremediation and medicinal mushrooms.- Research and advocacy :...

) as having potential as biological filters, removing chemicals and microorganism
Microorganism
A microorganism or microbe is a microscopic organism that comprises either a single cell , cell clusters, or no cell at all...

s from soil and water. The use of fungal mycelia to accomplish this has been termed "mycofiltration
Mycofiltration
Mycofiltration is the process of using mushroom mycelium mats as biological filters. The term was coined by mycologist Paul Stamets.Stamets originally came up with the technique to control E. coli in the water outflow from his property. After planting a mushroom bed in the gulch where the water was...

".

Knowledge of the relationship between mycorrhiza
Mycorrhiza
A mycorrhiza is a symbiotic association between a fungus and the roots of a vascular plant....

l fungi and plants suggests new ways to improve crop yield
Crop yield
In agriculture, crop yield is not only a measure of the yield of cereal per unit area of land under cultivation, yield is also the seed generation of the plant itself...

s.

When spread on logging roads, mycelium can act as a binder, holding new soil in place and preventing washouts until woody plants can be established.

Mycelium has been used to bind agricultural by-products to form products dubbed Greensulate
Greensulate
Greensulate is a renewable and biodegradable material that can be used for thermal insulation, fire insulation and also as a substitute for styrofoam and other plastics used in packaging and other applications....

 and Ecocradle, which are alternatives to plastic styrofoam
Styrofoam
Styrofoam is a trademark of The Dow Chemical Company for closed-cell currently made for thermal insulation and craft applications. In 1941, researchers in Dow's Chemical Physics Lab found a way to make foamed polystyrene...

 for packaging and insulation. Two inventors, Eben Bayer and Gavin McIntyre, and their company Ecovative Design LLC, developed the method to manipulate a network of mycelia into desirable shapes, with properties comparable to its plastic counterpart. The invention has won two awards and is now in use commercially by Steelcase
Steelcase
Steelcase is an international office furniture company founded in 1912 in Grand Rapids, Michigan — as The Metal Office Furniture Company. The company at the time specialized in file cabinets and safes. Today, the company sells products related to interior architecture, furniture and technology...

 as packaging for furniture. This use of mycelium has been discussed in Time Magazine, Popular Science and other media, as well as being the subject of a TED Talk "Are Mushrooms the New Plastic?" by Eben Bayer.http://www.ted.com/talks/eben_bayer_are_mushrooms_the_new_plastic.html

Is also used to produce mycoprotein- involved in the production of Quorn
Quorn
Quorn is the leading brand of mycoprotein food product in the UK and Ireland. The mycoprotein used to produce Quorn is extracted from a fungus, Fusarium venenatum, which is grown in large vats....

(a meat substitute for vegetarians).

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