Fungus

A single-celled or multicellular organism. Fungi can be true pathogens (such as histoplasmosis and coccidioidomycosis) that cause infections in healthy persons or they can be opportunistic pathogens (such as aspergillosis, candidiasis, and cryptococcosis) that cause infections in immunocompromised persons (including cancer patients, transplant recipients, and persons with AIDS). An example of a common fungus is the yeast organism which causes thrush and diaper rash (diaper dermatitis). Fungi are also used for the development of antibiotics, antitoxins, and other drugs used to control various human diseases.

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A general term used to encompass the diverse morphologic forms of yeasts and molds. Originally classified as primitive plants without chlorophyll, the fungi are placed in the kingdom Fungi and some in the kingdom Protista, along with the algae (all but the blue-green algae), the protozoa, and the slime molds. Fungi share with bacteria the important ability to break down complex organic substances of almost every type (cellulose) and are essential to the recycling of carbon and other elements in the cycle of life. Fungi are important as foods and to the fermentation process in the development of substances of industrial and medical importance, including alcohol, the antibiotics, other drugs, and foods. Relatively few fungi are pathogenic for humans, whereas most plant diseases are caused by fungi. [L. f., a mushroom]

- f. cerebri an ulcerated cerebral hernia with granulation tissue protruding from scalp wound.

- dematiaceous fungi (de-mat′e-a-ce-ous) dark fungi that form melanin. [Mod. L. Dematium (genus name), fr. g. demation, fine strand, fr. dema, band, fr. deo, to bind + suffix -aceous, characterized by]

- imperfect f. a f. in which the means of sexual reproduction is not yet recognized; these fungi generally reproduce by means of conidia.

- perfect f. a f. possessing both sexual and asexual means of reproduction, and in which both mating forms are recognized.

- ray f. a bacterium of the order Actinomycetales.

- thrush f. SYN: Candida albicans.

- umbilical f. a mass of granulation tissue on the stump of the umbilical cord in the newborn.

- yeast f. obsolete term for Saccharomyces.

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fun·gus 'fəŋ-gəs n, pl fun·gi 'fən-.jīalso 'fəŋ-.gī also fun·gus·es 'fəŋ-gə-səz often attrib

1) any of the kingdom Fungi of saprophytic and parasitic spore-producing eukaryotic typically filamentous organisms formerly classified as plants that lack chlorophyll and include molds, rusts, mildews, smuts, mushrooms, and yeasts

2) infection with a fungus

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n. (pl. fungi)

a simple organism (formerly regarded as a plant) that lacks the green pigment chlorophyll. Fungi include the yeast, rusts, moulds, and mushrooms. They live either as saprophyte or as parasite of plants and animals; some species infect and cause disease in humans. Some yeasts are a good source of vitamin B and many antibiotics are obtained from the moulds (see penicillin).

• fungal adj.

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fun·gus (fungґgəs) pl. funґgi [L.] an organism belonging to the Fungi. See also mycosis and mycotoxicosis. fungal adj