Pseudeurotium ovale
| Pseudeurotium ovale | |
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| Species: | Pseudeurotium ovale
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| Pseudeurotium ovale Mycotaxon: Doveri (2013)[1]
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Pseudeurotium ovale is a species of fungus.
History and taxonomy[edit]
Pseudeurotium ovale was first classified by Amelia C. Stolk in 1954.[5] It was assigned to the genus Pseudeurotium, along with thirteen other species.[6] It was initially classified as a member of the family Eurotiaceae, but was reclassified forty years later by Malloch and Cain to its current family, Pseudeurotiaceae.[6][7] Further more recent studies indicated that P. ovale could be classified as incertae sedis, as a result of analysis of conserved regions of its genome.[6] Pseudeurotium ovale was originally identified on Jersey, an island in the English Channel, but has since been isolated in various regions, including Japan, South Africa, Italy and Sweden.[8] Pseudeurotium ovale has been classified as a saprotroph, as it can thrive in a diverse set of environments, including soil, faeces and oatmeal agar.[5][9][10] In some instances, growths on the nematode Heterodera or Globodera rostochiensis have contained P. ovale.[5]
Growth and morphology[edit]
Pseudeurotium ovale is a member of the Ascomycota, and therefore the fruiting body of P. ovale is called an ascocarp.[9] Pseudeurotium ovale has a cleisothecium, or a fruiting body with a round shape.[9] The membrane of the cleisothecium is continuous, and the spore-bearing structures or asci, lack germ pores. These normally allow germ tubes to exit the ascospores after they disperse from the fruiting body, and germination begins.[9] The fungus germinates every 24 to 48 hours, and where the germ tube exits the fungal spores has yet to be identified.[5] P. ovale is very similar in appearance to both Cleistothelebolus nipigonensis and Cephalotheca palearum, however there are slight differences between their physical characteristics that make them identifiable.[5][9] The multilayered cell wall of Cephalotheca and the faecal-restricted growth environment for C. nipigonensis distinguish these fungi from P. ovale.[5][9]
Physiology[edit]
The smooth, dark brown, oval-shaped spores of Pseudeurotium ovale are unique compared to other members of the species.[9][10] The spore-bearing structures or asci are randomly distributed throughout the ascocarp in groups of eight.[9][10] They also range from being seven to nine microns in width, and six to eight microns in length.[9] The diameter of the fruiting body of P. ovale can be anywhere from 90 to 250 micrometers.[9] The tissue of its single layer peridium is described as being densely packed into irregular columns and rows of cells.[5][9] The cell wall of P. ovale spores are thin, growing into hyphae with no discernible septa.[10] Pseudeurotium ovale grows well below human body temperature, at around 25°C.[5] An asexual state of P. ovale has also been identified, and has been classified as sympodial.[9] The asexual spores or conidia of P. ovale form around three days after germination.[5]
Pathology[edit]
Pseudeurotium ovale has not been found to be causative in human disease. It has only ever been identified in a few cases of onychomycosis of the toe nails in elderly individuals.[11][12] Finger nails are very rarely infected by P. ovale.[12] In instances of P. ovale colonization of toenails, it was found with a dermatophyte, such as Trichophyton rubrum, or in an immunocompromised individual.[11] The nail appearance was severely altered, presenting with discolouration, and had lost their structural integrity.[11] In one infection, the dermatophyte Trichophyton rubrum was identified as the causative agent.[11] Pseudeurotium ovale has also been found with Cephalosporium sp. in cases of onychomycosis; however their role in disease was unclear.[11]
Medical applications[edit]
Some toxins produced by Pseudeurotium ovale have been found to have antimicrobial effects, and can act ton the immune response, dampening it in some cases.[13][14] Ovalicin is a secondary metabolite, produced by the mycelium. Its main component is β-trans-bergamotene, a volatile organic compound in sesquiterpene class.[13][14] Environmental stressors, such as competition with other fungi or nutrient depravation, can trigger P. ovale to produce ovalicin as a response.[14] Past studies have demonstrated the potential for ovalicin as a tumour suppressing drug, as it targets methionine aminopeptidase type 2.[15] This protein is common to endothelial cells and is necessary for the formation of new blood vessels, which allow tumour growth.[15] β-trans-begamotene is also produced by Aspergillus fumigatus.[14]
References[edit]
- ^ Doveri, Francesco; Sarrocco, Sabrina; Vannacci, Giovanni (April–June 2013). "Studies on three rare coprophilous plectomycetes from Italy". Mycotaxon. 124: 279–300 – via Mycotaxon.
- ^ "Pseudeorotium ovale". Mycobank. Retrieved 26 October 2019.
- ^ "Pseudeurotium ovale". GBIF. Retrieved 20 November 2019.
- ^ "Pseudeurotium ovale". GBIF. Retrieved 20 November 2019.
- ^ a b c d e f g h i Stolk, Amelia (9 April 1954). "The genera Anixiopsis Hansen and Pseudeurotium Van Beyma". Antonie van Leeuwenhoek. 1 (21): 65–79. doi:10.1007/BF02543800. PMID 14350602. S2CID 30646008.
- ^ a b c Sogonov, M.V.; Schroers, H.J.; Gams, W.; Dijksterhuis, J.; Summerbell, R.C. (March 2005). "The hyphomcete Teberdinia hygrophila gen. nov., sp. nov. and related anamorphs of Pseudeurotium species". Mycologia. 97 (3): 695–709 – via Taylor and Francis Online.
- ^ Dennis, R.W.G. (1968). British Ascomycetes. Lehre, Germany: Verlag Von J. Cramer. p. 337-342.
- ^ "Occurrences". Global Diversity Information Facility. Retrieved 20 November 2019.
- ^ a b c d e f g h i j k l Doveri, Francesco; Sarrocco, Sabrina; Vannacci, Giovanni (Spring 2013). "Studies on three rare coprophilous plectomycetes from Italy". Mycotaxon. 124: 279–300. doi:10.5248/124.279.
- ^ a b c d Ellis, Martin B.; Ellis, J. Pamela (1988). Microfungi on miscellaneous substrates: an identification handbook. Portland OR, USA: Timber Press. p. 136. ISBN 0-88192-115-7.
- ^ a b c d e English, M. P.; Harman, R. R. M.; Turvey, J. W. J. (1966). Pseudeurotium Ovalis in Toenails. London: Chelsea School of Chiropody. pp. 553–556.
- ^ a b Griffiths, Christopher; Barker, Jonathan; Bleiker, Tanya; Chalmers, Robert; Creamer, Daniel (2016). Rook's Textbook of Dermatology, 4 Volume Set. Vol. 4 (9 ed.). UK: John Wiley & Sons. p. 56. ISBN 9781118441190.
- ^ a b Cane, David; King, G. (9 September 1976). "The Biosynthesis of Ovalicin: Isolation of B-trans-Bergamotene". Tetrahedron Letters. 51: 4737–4740. doi:10.1016/S0040-4039(00)93013-2.
- ^ a b c d Kramer, Rolf; Abraham, Wolf-Rainer (2012). "Volatile sesquiterpenes from fungi: what are they good for?". Phytochem Rev. 11: 15–37. doi:10.1007/s11101-011-9216-2. hdl:10033/214221. S2CID 18550511.
- ^ a b Griffith, Eric; Su, Zhuang; Turk, Benjamin; Chen, Shaoping; Chang, Yie-Hwa; Wu, Zhuchun; Biemann, Klaus; Liu, Jun (1997). "Methionine aminopeptidase (type 2) is the common target for angiogenesis inhibitors AGM-1470 and ovalicin". Chemistry and Biology. 4 (6): 461–471. doi:10.1016/S1074-5521(97)90198-8. PMID 9224570.