Geomyces
Encyclopedia
Geomyces is a genus
of filamentous fungus
in the family
Myxotrichaceae
. Members of the genus are widespread in distribution, especially in northern temperate regions. Known to be psychrotolerant and associated with Arctic
permafrost
soils, they are equally prevalent in the air of domestic dwellings, and children's sandpits. Species of Geomyces have previously been placed in the genus Chrysosporium
.
that have chains of spore
s formed directly from the cells of the branches. Sometimes only the tips of the branches become spores. The spores (conidia) are 1-celled, and either white or yellow. The teleomorph of species in this genus, if they exist, are in Pseudogymnoascus or Gymnostellatospora.
Geomyces species are known to form ericoid mycorrhiza
e with the roots of alpine Ericales
and other perennial hosts, helping these plants adapt to low-nutrient environments.
The Geomyces are keratin
ophilic fungi, able to degrade hairs and nails. They have been investigated for possible use in the biodecomposition of waste poultry feathers.
Studies suggest that one biochemical mechanism of low-temperature tolerance is achieved by altering the composition and total content of fatty-acids in their membrane, a phenomenon called homeoviscous adaptation
.
. It is not yet certain if the fungus is a causative agent in the bat deaths, or merely an opportunistic pathogen. It is known however that Geomyces species are found in caves and bat hibernacula
, and have been isolated from the cave cricket Troglophilus neglectus.
sequences, Geomyces species have been implicated in the biodeterioration of antique and optical glass. Feeding off organic residues ubiquitously present on historical glass, such as dust or dead fungal and bacterial material, fungal colonization by Geomyces may ultimately lead to etching
, pit corrosion, or the formation of cracks or patina
s due to secretion of acidic metabolic byproducts, or penetration of fungal mycelia into the paint layer.
activity, have been isolated from an unidentified Geomyces isolate found in a soil sample from King George Island, Antarctica: ethyl asterrate, n-butyl asterrate, and geomycins A-C.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of filamentous 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...
in the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Myxotrichaceae
Myxotrichaceae
Myxotrichaceae is a family of fungi. Recent phylogenetic analysis suggests that the family's traditional classification in the order Onygenales is incorrect, and that it should be placed with the Leotiomycetes class.-Genera:*Byssoascus*Geomyces...
. Members of the genus are widespread in distribution, especially in northern temperate regions. Known to be psychrotolerant and associated with Arctic
Arctic
The Arctic is a region located at the northern-most part of the Earth. The Arctic consists of the Arctic Ocean and parts of Canada, Russia, Greenland, the United States, Norway, Sweden, Finland, and Iceland. The Arctic region consists of a vast, ice-covered ocean, surrounded by treeless permafrost...
permafrost
Permafrost
In geology, permafrost, cryotic soil or permafrost soil is soil at or below the freezing point of water for two or more years. Ice is not always present, as may be in the case of nonporous bedrock, but it frequently occurs and it may be in amounts exceeding the potential hydraulic saturation of...
soils, they are equally prevalent in the air of domestic dwellings, and children's sandpits. Species of Geomyces have previously been placed in the genus Chrysosporium
Chrysosporium
Chrysosporium is a type of hyaline hyphomycetes .Chrysosporium colonies are moderately fast growing, flat, white to tan to beige in colour; they often with a powdery or granular surface texture. Hyaline, one-celled are produced directly on vegetative hyphae by non-specialized conidiogenous cells...
.
Description
This genus is characterized by short but distinct branched conidiophoresConidium
Conidia, sometimes termed conidiospores, are asexual, non-motile spores of a fungus and are named after the greek word for dust, konia. They are also called mitospores due to the way they are generated through the cellular process of mitosis...
that have chains of 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...
s formed directly from the cells of the branches. Sometimes only the tips of the branches become spores. The spores (conidia) are 1-celled, and either white or yellow. The teleomorph of species in this genus, if they exist, are in Pseudogymnoascus or Gymnostellatospora.
Geomyces species are known to form ericoid mycorrhiza
Ericoid mycorrhiza
Ericoid mycorrhiza are a symbiotic relationship between fungi and the roots of plants from the order Ericales. Ericoid mycorrhiza are considered crucial for the success of the family Ericaceae in variety of edaphically stressful environments worldwide...
e with the roots of alpine Ericales
Ericales
The Ericales are a large and diverse order of dicotyledons, including for example tea, persimmon, blueberry, Brazil nut, and azalea. The order includes trees and bushes, lianas and herbaceous plants. Together with ordinary autophytic plants, the Ericales include chlorophyll-deficient...
and other perennial hosts, helping these plants adapt to low-nutrient environments.
The Geomyces are keratin
Keratin
Keratin refers to a family of fibrous structural proteins. Keratin is the key of structural material making up the outer layer of human skin. It is also the key structural component of hair and nails...
ophilic fungi, able to degrade hairs and nails. They have been investigated for possible use in the biodecomposition of waste poultry feathers.
Adaptive capabilities
Research has shown that laboratory cultures of G. pannorum isolated from various environments may have extreme differences in morphology and physiology. In fact, the limits of cold adaptation in a particular isolate can vary depending on the source of isolation, even though the isolates are genetically identical.Studies suggest that one biochemical mechanism of low-temperature tolerance is achieved by altering the composition and total content of fatty-acids in their membrane, a phenomenon called homeoviscous adaptation
Homeoviscous adaptation
The maintenance of proper cell membrane fluidity is of critical importance for the function and integrity of the cell, essential for the mobility and function of embedded proteins and lipids, diffusion of proteins and other molecules laterally across the membrane for signaling reactions, and...
.
White-nose syndrome
A 2008 study of white-nose syndrome, a fungal infection causing high mortality rates in bats, determined that the fungus found on the muzzles, wings, and ears of infected bats is a member of the Geomyces genus. Later, the conidial morphology of this isolate was shown to be morphologically distinct from the conidia of other characterized members of the genus, despite the phylogenetic similarity. Finally, in spring 2009 the source of the infection was identified as a new species, Geomyces destructansGeomyces destructans
Geomyces destructans is a psychrophilic fungus that is associated with White nose syndrome , a fatal disease that has decimated bat populations in parts of the US. Unlike other species of Geomyces, Geomyces destructans forms asymmetrically curved conidia...
. It is not yet certain if the fungus is a causative agent in the bat deaths, or merely an opportunistic pathogen. It is known however that Geomyces species are found in caves and bat hibernacula
Hibernaculum (zoology)
Hibernaculum plural form: hibernacula is a word used in zoology to refer to a place of abode in which a creature seeks refuge, such as a bear using a cave to overwinter. Insects may hibernate to survive the winter. The word can be used to describe a variety of shelters used by various kinds of...
, and have been isolated from the cave cricket Troglophilus neglectus.
Biocorrosion
Using phylogenetic analyses of ribosomal DNARibosomal DNA
Ribosomal DNA codes for ribosomal RNA. The ribosome is an intracellular macromolecule that produces proteins or polypeptide chains. The ribosome itself consists of a composite of proteins and RNA. As shown in the figure, rDNA consists of a tandem repeat of a unit segment, an operon, composed of...
sequences, Geomyces species have been implicated in the biodeterioration of antique and optical glass. Feeding off organic residues ubiquitously present on historical glass, such as dust or dead fungal and bacterial material, fungal colonization by Geomyces may ultimately lead to etching
Etching
Etching is the process of using strong acid or mordant to cut into the unprotected parts of a metal surface to create a design in intaglio in the metal...
, pit corrosion, or the formation of cracks or patina
Patina
Patina is a tarnish that forms on the surface of bronze and similar metals ; a sheen on wooden furniture produced by age, wear, and polishing; or any such acquired change of a surface through age and exposure...
s due to secretion of acidic metabolic byproducts, or penetration of fungal mycelia into the paint layer.
Bioactive compounds
A number of asterric acid derivatives, some with antibacterial or antifungalAntifungal
* Antifungal medication, a medication used to treat fungal infection s such as athlete's foot , ringworm, candidiasis, etc.* Antifungal protein, a protein family* an adjective referring to a fungicide compound...
activity, have been isolated from an unidentified Geomyces isolate found in a soil sample from King George Island, Antarctica: ethyl asterrate, n-butyl asterrate, and geomycins A-C.
Species
- Geomyces asperulatus Sigler & J.W. Carmich. (1976)
- Geomyces auratus Traaen (1914)
- Geomyces cretaceus Traaen (1914)
- Geomyces destructansGeomyces destructansGeomyces destructans is a psychrophilic fungus that is associated with White nose syndrome , a fatal disease that has decimated bat populations in parts of the US. Unlike other species of Geomyces, Geomyces destructans forms asymmetrically curved conidia...
Gargas et al. (2009) - Geomyces laevis Zhong Q. Li & C.Q. Cui (1989)
- Geomyces pannorum (Link) Sigler & J.W. Carmich. (1976)
- This species is ubiquitous in soil, from temperate to AntarcticAntarcticThe Antarctic is the region around the Earth's South Pole, opposite the Arctic region around the North Pole. The Antarctic comprises the continent of Antarctica and the ice shelves, waters and island territories in the Southern Ocean situated south of the Antarctic Convergence...
regions, and is the predominant micro-organism associated with the degradation of soil-buried polyesterPolyesterPolyester is a category of polymers which contain the ester functional group in their main chain. Although there are many polyesters, the term "polyester" as a specific material most commonly refers to polyethylene terephthalate...
polyurethanePolyurethaneA polyurethane is any polymer composed of a chain of organic units joined by carbamate links. Polyurethane polymers are formed through step-growth polymerization, by reacting a monomer with another monomer in the presence of a catalyst.Polyurethanes are...
in landfillLandfillA landfill site , is a site for the disposal of waste materials by burial and is the oldest form of waste treatment...
s. The variant G. pannorum var. pannorum is occasionally reported as an etiological agent of superficial infection of skin and nails in humans.
- Geomyces pulvereus A.D. Hocking & Pitt (1988)
- Geomyces sulphureus Traaen
- Geomyces vinaceus Dal Vesco (1957)
- Named for the purplish-red or vinaceous colony color. The teleomorph form is Pseudogymnoascus roseus.