Geomyces

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Geomyces[1]
Scientific classification
Kingdom: Fungi
Subkingdom: Dikarya
Phylum: Ascomycota
Subphylum: Pezizomycotina
Class: Leotiomycetes
Order: Helotiales
Family: Myxotrichaceae
Genus: Geomyces
Traaen (1914)
Type species
Geomyces auratus
Traaen (1914)

Geomyces is a genus of filamentous fungus in the family Myxotrichaceae. Members of the genus are widespread in distribution, especially in northern temperate regions.[2] Known to be psychrotolerant and associated with Arctic permafrost soils,[3][4] they are equally prevalent in the air of domestic dwellings,[5] and children's sandpits.[6] Species of Geomyces have previously been placed in the genus Chrysosporium.[7]

Description[edit]

This genus is characterized by short but distinct branched conidiophores that have chains of spores formed directly from the cells of the branches.[8] Sometimes only the tips of the branches become spores. The spores (conidia) are 1-celled, and either white or yellow.[8] The teleomorph of species in this genus, if they exist, are in Pseudogymnoascus or Gymnostellatospora.

Geomyces species are known to form ericoid mycorrhizae with the roots of alpine Ericales and other perennial hosts, helping these plants adapt to low-nutrient environments.[9]

The Geomyces are keratinophilic fungi, able to degrade hairs and nails. They have been investigated for possible use in the biodecomposition of waste poultry feathers.[10]

Adaptive capabilities[edit]

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.[11]

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,[12][13] a phenomenon called homeoviscous adaptation.

White-nose syndrome[edit]

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.[4] 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.[3] Finally, in spring 2009 the source of the infection was identified as a new species, Geomyces destructans.[14] 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,[15] and have been isolated from the cave cricket Troglophilus neglectus.[16]

Biocorrosion[edit]

Using phylogenetic analyses of ribosomal DNA sequences, Geomyces species have been implicated in the biodeterioration of antique and optical glass.[17] Feeding off organic residues ubiquitously present on historical glass, such as dust or dead fungal and bacterial material,[18] fungal colonization by Geomyces may ultimately lead to etching, pit corrosion, or the formation of cracks or patinas due to secretion of acidic metabolic byproducts, or penetration of fungal mycelia into the paint layer.[19]

Bioactive compounds[edit]

A number of asterric acid derivatives, some with antibacterial or antifungal 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.[20]

Species[edit]

This species is ubiquitous in soil, from temperate to Antarctic regions, and is the predominant micro-organism associated with the degradation of soil-buried polyester polyurethane in landfills.[7][21] The variant G. pannorum var. pannorum is occasionally reported as an etiological agent of superficial infection of skin and nails in humans.[22]
Named for the purplish-red or vinaceous colony color. The teleomorph form is Pseudogymnoascus roseus.

References[edit]

  1. ^ "UniProt: Geomyces". Retrieved 2008-11-03. 
  2. ^ Bisby, Guy Richard; Ainsworth, G. C.; Kirk, P. M.; Aptroot, André (2001). Ainsworth & Bisby's Dictionary of the fungi / by P. M. Kirk... [et al.]; with the assistance of A. Aptroot... [et al.] Oxon: CAB International. ISBN 0-85199-377-X. 
  3. ^ a b Blehert DS, Hicks AC, Behr M, et al. (October 2008). "Bat White-Nose Syndrome: An Emerging Fungal Pathogen?". Science 323 (5911): 227. doi:10.1126/science.1163874. PMID 18974316. Retrieved 2008-11-02. 
  4. ^ a b National Geographic: "Deadly Bat Disease Linked to Cold-Loving Fungus". Retrieved 2008-11-02. 
  5. ^ Hunter CA, Grant C, Flannigan B, Bravery AF. (1988). Mould in buildings. The air spora of domestic dwellings. International Biodeterioration 24(2): 81-102.
  6. ^ <Marchisio VF. (1986). Keratinolytic and keratinophlic fungi of children's sandpits in the city of Turin Italy. Mycopathologia 94(3): 163-172.
  7. ^ a b "Geomyces pannorum". Retrieved 2008-11-02. 
  8. ^ a b "Geomyces". Retrieved 2008-12-07. 
  9. ^ Dalpe Y, Litton W, Sigler L. (1989). Scyalidium vaccinii sp. nov., an ericoid endophyte of Vaccinium angustifolium roots. Mycotaxon 35: 371-377.
  10. ^ Saxena P, Kumar A, Shrivastava JN. (2005). Keratinophilic fungi: A microbial way to manage poultry waste feathers. Indian Journal of Microbiology 45(2): 151-154.
  11. ^ Kochkina GA, Ivanushkina NE, Akimov VN, Gilichinskii DA, Ozerskaya SM. (2007). Halo- and psychrotolerant Geomyces fungi from Arctic cryopegs and marine deposits. Microbiology 76(1): 31-38.
  12. ^ Finottei E, Moretto D, Marsella R, Mercantini R. (1993). Temperature effects and fatty-acid patterns in Geomyces species isolated from Antarctic soil. Polar Biology 13(2): 127-130.
  13. ^ Weinstein RN, Montiel PO, Johnstone K. (2000). Influence of growth temperature on lipid and soluble carbohydrate synthesis by fungi isolated from Fellfield soil in the maritime Antarctic. Mycologia 92(2): 222–229.
  14. ^ Gargas A, Trest MT, Christensen M, Volk TJ, Blehert DS (April–June 2009). "Geomyces destructans sp. nov. associated with bat white-nose syndrome". Mycotaxon 108: 147–154. doi:10.5248/108.147. Retrieved 2009-09-03. 
  15. ^ Mosca AML, Campanino F. (1962). Soil mycological analyses of natural caves in the Piedmont. Allonia 8: 27-43.
  16. ^ Gunde-Cimerman N, Zalar P, Glavan G, Cimerman A. (1996). Extracellular enzymatic activities of fungi isolated from the cave cricket Troglophilus neglectus. Mededelingen Faculteit Landbouwkundige en Toegepaste Biologische Wetenschappen Universiteit Gent 61(4A-B): 1425-1426.
  17. ^ Schabereiter-Gurtner C, Piñar G, Lubitz W, Rölleke S. (2001). Analysis of fungal communities on historical church window glass by denaturing gradient gel electrophoresis and phylogenetic 18S rDNA sequence analysis. Journal of Microbiological Methods 47(3): 345-354.
  18. ^ Karpovich-Tate N, Rebrikova NL. (1990). Microbial communities on damaged frescoes and building materials in the cathedral of the nativity of the virgin in the Pafnutii-Borovskii monastery, Russia. Int. Biodeterior. 27, 281–296.
  19. ^ Berner M, Wanner G, Lubitz W. (1997). A comparative study of the fungal flora present in medieval wall paintings in the chapel of the castle Herberstein and in the parish church of St. Georgen in Styria, Austria. Int. Biodeterior. Biodegrad. 40: 53–61.
  20. ^ Li Y, Sun B, Liu S, Jiang L, Liu X, Zhang H, Che Y (September 2008). "Bioactive asterric acid derivatives from the Antarctic ascomycete fungus Geomyces sp". J. Nat. Prod. 71 (9): 1643–6. doi:10.1021/np8003003. PMID 18720971. 
  21. ^ Cosgrove L, McGeechan PL, Robson GD, Handley PS (September 2007). "Fungal Communities Associated with Degradation of Polyester Polyurethane in Soil". Applied and environmental microbiology 73 (18): 5817–24. doi:10.1128/AEM.01083-07. PMC 2074895. PMID 17660302. Retrieved 2008-11-02. 
  22. ^ Gianni C, Caretta G, Romano C (2003). "Skin infection due to Geomyces pannorum var. pannorum". Mycoses 46 (9–10): 430–2. doi:10.1046/j.1439-0507.2003.00897.x. PMID 14622395. Retrieved 2008-12-06. 

External links[edit]