Chytridiomycota: Difference between revisions
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==Fossil record== |
==Fossil record== |
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The earliest [[fossil]]s of chytrids are from the [[Scotland|Scottish]] [[Rhynie chert]], a [[Devonian]]-age locality with anatomical preservation of [[plant]]s and fungi. Among the microfossils are chytrids preserved as [[parasite]]s on [[rhyniophyte]]s. These fossils closely resemble the genus ''[[Allomyces]]''.<ref>{{cite journal | author = Taylor, T.N. | coauthors = W. Remy, & H. Hass. | year = 1994 | title = ''Allomyces'' in the Devonian | journal = Nature | volume=367 | pages=601 | doi = 10.1038/367601a0 | issue=6464}}</ref> Holocarpic chytrid remains were found in cherts from Combres in central France that dates back to the late [[Visean]]. These remains were found along eucarpic remains and are ambiguous in nature though are thought to be chytrid remains. <ref>{{cite journal | author = Krings, Micheal | coauthors = Nora Dotzler, Thomas Taylor, & Jean Galtier. | year = 2009 | title = Microfungi from the upper Visean (Mississippian) of central France: Chytridiomycota and chytrid-like remains of uncertain affinity | journal = Review of Palaeobotany and Palynology | volume=156 | pages=319-328 | doi = 10.1016/j.revpalbo.2009.03.011 | issue=3-4}}</ref> Other chytrid-like fossils were found in cherts in Western Europe, especially France, dating between 300 and 350[[ma]]. Another such example is the chert from the upper [[Pennsylvanian]] in the [[Saint-Etienne Basic]] in [[France]]. <ref>{{cite journal | author = Krings, Micheal | coauthors = Jean Galtier, Thomas N. Taylor, and Nora Dotzler. | year = 2009 | title = Chytrid-like microfungi in Biscalitheca cf. musata (Zygopteridales) from the Upper Pennsylvanian Grand-Croix cherts (Saint-Etienne Basin, France). | journal = Review of Palaeobotany and Palynology | volume=157 | pages=309-316 | doi = 10.1016/j.revpalbo.2009.06.001 | issue=3-4}}</ref> While none of the fossils found before the [[Permian]] [[System_(stratigraphy)|system]] are specifically chytrids, their chytrid-like qualities give impressive insight into the evolutionary path of Fungi. |
The earliest [[fossil]]s of chytrids are from the [[Scotland|Scottish]] [[Rhynie chert]], a [[Devonian]]-age locality with anatomical preservation of [[plant]]s and fungi. Among the microfossils are chytrids preserved as [[parasite]]s on [[rhyniophyte]]s. These fossils closely resemble the genus ''[[Allomyces]]''.<ref>{{cite journal | author = Taylor, T.N. | coauthors = W. Remy, & H. Hass. | year = 1994 | title = ''Allomyces'' in the Devonian | journal = Nature | volume=367 | pages=601 | doi = 10.1038/367601a0 | issue=6464}}</ref> Holocarpic chytrid remains were found in cherts from Combres in central France that dates back to the late [[Visean]]. These remains were found along eucarpic remains and are ambiguous in nature though are thought to be chytrid remains. <ref>{{cite journal | author = Krings, Micheal | coauthors = Nora Dotzler, Thomas Taylor, & Jean Galtier. | year = 2009 | title = Microfungi from the upper Visean (Mississippian) of central France: Chytridiomycota and chytrid-like remains of uncertain affinity | journal = Review of Palaeobotany and Palynology | volume=156 | pages=319-328 | doi = 10.1016/j.revpalbo.2009.03.011 | issue=3-4}}</ref> Other chytrid-like fossils were found in cherts in Western Europe, especially France, dating between 300 and 350[[Mya_(unit)|ma]]. Another such example is the chert from the upper [[Pennsylvanian]] in the [[Saint-Etienne Basic]] in [[France]]. <ref>{{cite journal | author = Krings, Micheal | coauthors = Jean Galtier, Thomas N. Taylor, and Nora Dotzler. | year = 2009 | title = Chytrid-like microfungi in Biscalitheca cf. musata (Zygopteridales) from the Upper Pennsylvanian Grand-Croix cherts (Saint-Etienne Basin, France). | journal = Review of Palaeobotany and Palynology | volume=157 | pages=309-316 | doi = 10.1016/j.revpalbo.2009.06.001 | issue=3-4}}</ref> While none of the fossils found before the [[Permian]] [[System_(stratigraphy)|system]] are specifically chytrids, their chytrid-like qualities give impressive insight into the evolutionary path of Fungi. |
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==In popular culture== |
==In popular culture== |
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Revision as of 21:28, 23 October 2013
| Chytridiomycota Temporal range:
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Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Fungi |
| Division: | Chytridiomycota M.J. Powell 2007[1] |
| Type species | |
| Chytridium spp. A. Braun, 1851
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Chytridiomycota is a division of the kingdom Fungi. The name is derived from the Greek chytridion, meaning "little pot", describing the structure containing unreleased spores. In older classifications, chytrids (except the recently established order Spizellomycetales) were placed in the class Phycomycetes under the subdivision Myxomycophyta of the kingdom Fungi. Also, in an older and more restricted sense (not used here), the term "chytrids" referred just to those fungi in the order Chytridiales. The chytrids have also been included among the Protista, but are now regularly classed as fungi.
The chytrids are one of the early diverging lineages of the fungi and are mostly saprobic, degrading refractory materials such as chitin and keratin. The thalli are coenocytic and usually form no true mycelium (having rhizoids instead). Some species are unicellular. As with other fungi, the cell wall in chytrids is composed of chitin.
Many chytrids are aquatic (mostly found in fresh water). There are approximately 1,000 chytrid species, in 127 genera, distributed among 5 orders.
Reproduction
Both zoospores and gametes of the chytrids are mobile by their flagella, one whiplash per individual.
In Allomyces, the thallus (body) is attached by rhizoids, and has an erect trunk on which reproductive organs are formed at the end of branches. The life cycle has the ability to change from haploid and diploid generations. The haploid thallus forms male and female gametangia from which flagellated gametes are released and merge to form a Zygote. Gametes and female gametangia attract the opposite sex by producing pheromones. The germinated zygote produces a diploid thallus with two sorts of sporangia; thin-walled zoosporangia which release diploid zoospores resulting in a diploid thalli and thick-walled sporangia which after meiosis release haploid zoospores which form haploid thalli.
As a parasite
The chytrid Batrachochytrium dendrobatidis (itself commonly known as "Chytrid"[2]) is responsible for a recently discovered disease of amphibians, chytridiomycosis. Discovered in 1998 in Australia and Panama this disease is known to kill amphibians in large numbers, and has been suggested as a principal cause for the worldwide amphibian decline. In one example an outbreak of the fungus was found responsible for killing much of the Kihansi Spray Toad population in its native habitat of Tanzania.[3] Another example is that it's also responsible for the extinction of the golden toad in 1989. The process leading to frog mortality is thought to be the loss of essential ions through pores made in the epidermal cells by the chytrid during its replication. [4]
Chytrids may also infect plant species; in particular, maize-attacking and alfalfa-attacking species have been described. Synchytrium endobioticum is an important potato pathogen.
Fossil record
The earliest fossils of chytrids are from the Scottish Rhynie chert, a Devonian-age locality with anatomical preservation of plants and fungi. Among the microfossils are chytrids preserved as parasites on rhyniophytes. These fossils closely resemble the genus Allomyces.[5] Holocarpic chytrid remains were found in cherts from Combres in central France that dates back to the late Visean. These remains were found along eucarpic remains and are ambiguous in nature though are thought to be chytrid remains. [6] Other chytrid-like fossils were found in cherts in Western Europe, especially France, dating between 300 and 350ma. Another such example is the chert from the upper Pennsylvanian in the Saint-Etienne Basic in France. [7] While none of the fossils found before the Permian system are specifically chytrids, their chytrid-like qualities give impressive insight into the evolutionary path of Fungi.
In popular culture
Tom Clancy's Splinter Cell: Fallout (2007), a novel by Tom Clancy, features a species of the chytridiomycota fungus that feeds on petroleum and oil-based products. The species is enhanced using nuclear radiation, increasing its survivability and rate of feeding. It is then used by Islamic extremists in an attempt to destroy the world's oil supplies, thereby taking away the technological advantage of the United States.[8]
References
- ^ Hibbett, D.S.; et al. (2007). "A higher level phylogenetic classification of the Fungi". Mycol. Res. 111 (5): 509–547. doi:10.1016/j.mycres.2007.03.004. PMID 17572334.
{{cite journal}}: Explicit use of et al. in:|author=(help); Unknown parameter|month=ignored (help) - ^ http://reporting.journalism.ku.edu/fall06/fred-musser/2006/12/pandemic_fungus_killing_frogs.html
- ^ Saving Tiny Toads Without a Home, by Cornelia Dean. The New York Times. February 1, 2010.
- ^ (Voyles, J., L. Berger, S. Young, et al. 2007. Electrolyte depletion and osmotic imbalance in amphibians with chytridiomycosis. Dis Aquat Organ. 77: 113-118.)
- ^ Taylor, T.N. (1994). "Allomyces in the Devonian". Nature. 367 (6464): 601. doi:10.1038/367601a0.
{{cite journal}}: Unknown parameter|coauthors=ignored (|author=suggested) (help) - ^ Krings, Micheal (2009). "Microfungi from the upper Visean (Mississippian) of central France: Chytridiomycota and chytrid-like remains of uncertain affinity". Review of Palaeobotany and Palynology. 156 (3–4): 319–328. doi:10.1016/j.revpalbo.2009.03.011.
{{cite journal}}: Unknown parameter|coauthors=ignored (|author=suggested) (help) - ^ Krings, Micheal (2009). "Chytrid-like microfungi in Biscalitheca cf. musata (Zygopteridales) from the Upper Pennsylvanian Grand-Croix cherts (Saint-Etienne Basin, France)". Review of Palaeobotany and Palynology. 157 (3–4): 309–316. doi:10.1016/j.revpalbo.2009.06.001.
{{cite journal}}: Unknown parameter|coauthors=ignored (|author=suggested) (help) - ^ Michaels, David (2007). Tom Clancy's Splinter Cell: Fallout. Penguin Group. ISBN 978-0-425-21824-2.
External links
- Chytrid Fungi Online: by the University of Alabama
- Introduction to the Chytridiomycota: at the UC Museum of Paleontology
- Impact of chytrid fungus on frogs (Foundation for National Parks & Wildlife)
- 'Amphibian Ark' aims to save frogs from fungus
- The Aquarium Wiki Encyclopaedia on Chytrid Fungus and how it impacts amphibians kept as domestic pets.
- NIH
- Chytridiomycota at the U.S. National Library of Medicine Medical Subject Headings (MeSH)