Endocrinology

What Is Fungus? What Are Fungi?

of fungi (Mycology) was a subdivision of botany. Robert H. Wittaker (USA, 1920-1980) a vegetation ecologist introduced a 5-Kingdom taxonomy, granting fungi equal status with animals and plants. The 5-Kingdom taxonomy included: *Kingdom Animalia (animal kingdom) *The Kingdom Plantae (plant kingdom) *Kingdom Fungi (fungi kingdom) *Kingdom Protista (types of eukaryotic organisms; containing complex structures enclosed within membranes) *Kingdom Monera (types of microscopic single-celled organisms whose genetic material is loose in the cell, instead of being held in the cell"s nucleus) Today some countries, such as the USA use a 6-Kingdom system: *Kingdom Animalia *Kingdom Plantae *Kingdom Fungi *Kingdom Protista *Kingdom Archaea *Kingdom Bacteria Archaea are single-cell microorganisms with no nucleus or other microscopic organ-like parts (organelles). while many British, Irish and Australasian scientists use a 5-Kingdom system: *Kingdom Animalia *Kingdom Plantae *Kingdom Fungi *Kingdom Protista *Kingdom Prokaryota/Monera Current mycologists say that as some slime molds, mildews and water molds have similar feeding stages to amoebas, plus some other qualities, they should be part of a separate kingdom called Kingdom Protista, while others talk about Kingdom Stremenopila for water molds and downy mildews that have no chitin, as well as some other characteristics. Kingdoms are divided into phila Today, the main criteria for fungus classification is the type of spores and fruiting bodies it produces. All Kingdoms are divided into phyla (singular: phylum). A phylum is a primary division of a kingdom. Fungi are commonly divided into four broad phyla: *Chytridiomycota (Chytrids) - these are microscopic fungi and are mostly found in freshwater or damp/drenched soil. The majority of chytrids are parasites of algae and animals. Some are saprobes (living on decomposed organic matter). A chytrid called Batrachochytrium dendrobatidis causes disease in amphibians. Scientists have identified over 800 species of chytrids. *Zygomycota - these mold that forms on bread and many other foods. The mold has tiny black dots (sporangia) which produce sporangiospores - asexual spores. Many types of zygomycota are insect and spider parasites. *Ascomycota - there are about 33,000 identified species of ascomycetes that feed on both living and dead matter. Ascomycetes are primary decomposers of plants. They are also important causes of plant and human diseases. They are used in brewing, baking, winemaking, and as s of therapeutic drugs. They are also used in the production of some cheeses, such as Camembert, Roquefort and Stilton. *Basidiomycota - Both edible and poisonous mushrooms are types of basidiomicetes. They cause devastating plant diseases. Basidiomicetes are commonly found in birds" nests. Most decomposition of living or dead wood that occurs in forests as well as inside man-made structures is caused by basidiomicetes. Leaf ants live exclusively on a type of basidiomicetes, as do some termites. Cryptococcosis, a human infection caused by inhaling a basidiomicetes fungus called Cryptococcus neoformans, commonly infects patients with weakened immune systems, such as those with HIV/AIDS, or people receiving medications that suppress their immune system. Infection is usually limited to the lungs, but can spread to other parts of the body, causing meningitis. What do humans use fungi for? *Fungi as a food or used in food preparation Humans have been eating fungi since before we started walking on our hind legs. Today we eat an enormous variety of edible fungi, including truffles, mushrooms, quorn, shitake and hundreds others. We also use fungi, e.g. yeast, in food manufacturing. Yeast is needed for the fermentation of wine, beers and other alcoholic drinks. We add yeast to dough to make the bread rise when we bake it. *Fungi used in industry and agriculture Fungi are used in the production of ethanol. They are used extensively to produce industrial chemicals, such as citric acid, gluconic acid, malic acid, and biological detergents. The production of many deliberately faded garments would be much more difficult without using fungi. They are used in bioremediation - the detoxification of polluted water or soil. Fungi are also used in agriculture for pest control and to protect crops from diseases. *Fungi used in medicine *Antibiotics - Many types of antibiotics come from fungi, such as penicillin (Penicillium chrysogenum), cephalosporin (Acremonium) , and griseofulvin (Penicillium griseofulvin). Penicillin works by destroying the wall of a bacterial cell. Fungal antibiotics are extensively used for treating tuberculosis, syphilis, and leprosy, to name but a few diseases. *Chemotherapy - Antibacterial chemotherapy uses fungi. Lentilan, a drug used in cancer treatment, is d from the shiitake mushroom. *Immunosuppressants - Cyclosporin is a medication that transplant patients take to suppress their immune system. It is produced by the fungus Beauveria nivea and significantly lowers the risk of transplanted organ refection. Many successful transplant procedures could not have occurred without this drug. Laboratory studies indicate that Agaricus blazei may stimulate the human immune system and could have major implications for human health - especially in the treatment of many cancers. US researchers reported that a rapid production of therapeutic human drugs using modified mushrooms may help mount a quicker response to various public health problems. The reishi mushroom (Ganoderma lucidum) and green tea may both enhance the body"s immune functions and hold the potential for treatment and prevention of many types of cancer, scientists from Pharmanex BJ Clinical Pharmacology Center in Beijing reported. Extracts of the mushroom Phellinus linteus may halt breast cancer growth , according to scientists from the Methodist Research Institute in Indianapolis, USA. *Traditional Chinese Medicine includes several types of mushrooms, such as Agaricus, Ganoderma, and Cordyceps among its various therapies. Fungi that cause human diseases - pathogenic fungi Mycosis is a disease caused by a fungus (plural: mycoses). Fungi that cause diseases are called pathogenic fungi. Mycoses can be divided into four broad groups; these groups are classified according to how deeply the fungus penetrates into the body: *Superficial mycosis The fungus does not penetrate at all. It is present only on the surface of the skin or on the patient"s hair. This may include various types of ringworm (tinea), including athlete"s foot, scalp ringworm, and body (skin) ringworm. Candida albicans is a yeast that causes candidiasis. As a superficial mycosis candidiasis usually affects the vagina of females or the mouth of both males and females. It exists normally in the vagina or gastrointestinal tract, but may multiply rapidly, especially if the person is ill or has a weakened immune system. Taking antibiotics may sometimes result in rapid reproduction of Candida albicans. Fungi that obtain nutrients from keratinized material are called dermatophytes. Dermatophytes cause superficial and cutaneous mycosis (below). *Cutaneous mycosis The infection is generally limited to the nonliving keratinized layers of skin, hair, and nails - no living tissue is invaded. Also includes tinea (ringworm), as well as candidiasis of the skin, mucus membranes and nails (Candida albicans and related species). *Subcutaneous mycosis The fungi reach below the skin and infect subcutaneous (area just below the skin), connective and bone tissue. These infections are usually chronic (long-lasting) and often occur when the skin is pierced or wounded, allowing the fungi to enter, usually in the form of vegetable matter. These infections may be hard to treat and often require removal of damaged skin (debridement). Subcutaneous mycoses are much more common in the tropics. Sporotrichosis caused by Sporothrix schenckii is an example of subcutaneous mycosis. Sporotrichosis used to be common in Europe, but is very rare there today. It is more common in Australia, South Africa and in the warmer regions of the Americas. Infection may occur as a result of an insect bite, a thorn prick or a scratch from any sharp object. Infection risk is higher among florists, farmers, gardeners and people who work with hay and moss. *Systemic mycosis This is a fungal infection that may reach any part of the body, including the brain and heart, as well as the bloodstream. The fungi usually enter via the lungs, gastrointestinal tract or intravenously. An example of systemic mycosis is cryptococcosis, which is caused by Cryptococcus neoformans, a type of yeast. It can cause subacute or chronic meningitis. The fungi enter the body by inhalation. Infected patients may also develop lung infections. Cryptococcus neoformans may be found in pigeon droppings. Written by Christian Nordqvist Copyright: Medical News Today Not to be reproduced without permission of Medical News Today

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