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.[4] It was assigned to the genus Pseudeurotium, along with thirteen other species.[5] 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.[5][6] 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.[5] 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.[7] Pseudeurotium ovale has been classified as a saprotroph, as it can thrive in a diverse set of environments, including soil, faeces and oatmeal agar.[4][8][9] In some instances, growths on the nematode Heterodera or Globodera rostochiensis have contained P. ovale.[4]
Growth and morphology
[edit]Pseudeurotium ovale is a member of the Ascomycota, and therefore the fruiting body of P. ovale is called an ascocarp.[8] Pseudeurotium ovale has a cleisothecium, or a fruiting body with a round shape.[8] 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.[8] The fungus germinates every 24 to 48 hours, and where the germ tube exits the fungal spores has yet to be identified.[4] 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.[4][8] The multilayered cell wall of Cephalotheca and the faecal-restricted growth environment for C. nipigonensis distinguish these fungi from P. ovale.[4][8]
Physiology
[edit]The smooth, dark brown, oval-shaped spores of Pseudeurotium ovale are unique compared to other members of the species.[8][9] The spore-bearing structures or asci are randomly distributed throughout the ascocarp in groups of eight.[8][9] They also range from being seven to nine microns in width, and six to eight microns in length.[8] The diameter of the fruiting body of P. ovale can be anywhere from 90 to 250 micrometers.[8] The tissue of its single layer peridium is described as being densely packed into irregular columns and rows of cells.[4][8] The cell wall of P. ovale spores are thin, growing into hyphae with no discernible septa.[9] Pseudeurotium ovale grows well below human body temperature, at around 25 °C.[4] An asexual state of P. ovale has also been identified, and has been classified as sympodial.[8] The asexual spores or conidia of P. ovale form around three days after germination.[4]
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.[10][11] Finger nails are very rarely infected by P. ovale.[11] In instances of P. ovale colonization of toenails, it was found with a dermatophyte, such as Trichophyton rubrum, or in an immunocompromised individual.[10] The nail appearance was severely altered, presenting with discolouration, and had lost their structural integrity.[10] In one infection, the dermatophyte Trichophyton rubrum was identified as the causative agent.[10] Pseudeurotium ovale has also been found with Cephalosporium sp. in cases of onychomycosis; however their role in disease was unclear.[10]
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.[12][13] Ovalicin is a secondary metabolite, produced by the mycelium. Its main component is β-trans-bergamotene, a volatile organic compound in sesquiterpene class.[12][13] Environmental stressors, such as competition with other fungi or nutrient deprivation, can trigger P. ovale to produce ovalicin as a response.[13] Past studies have demonstrated the potential for ovalicin as a tumour suppressing drug, as it targets methionine aminopeptidase type 2.[14] This protein is common to endothelial cells and is necessary for the formation of new blood vessels, which allow tumour growth.[14] β-trans-begamotene is also produced by Aspergillus fumigatus.[13]
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.
- ^ a b "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.