Didinium
Didinium | |
---|---|
Didinium nasutum as illustrated by Schewiakoff , 1896
| |
Scientific classification | |
Domain: | Eukaryota |
Clade: | Diaphoretickes |
Clade: | SAR |
Clade: | Alveolata |
Phylum: | Ciliophora |
Class: | Litostomatea |
Order: | Haptorida |
Family: | Didiniidae |
Genus: | Didinium Stein, 1859 |
Didinium is a
Appearance and reproduction
Didinia are rounded, oval, or barrel-shaped and range in length from 50 to 150
The macronucleus is long and may be curved, horseshoe-shaped, or twisted into a shape resembling a figure eight.[7] A contractile vacuole and anal aperture are in the posterior of the cell.[8]
Like all ciliates, Didinia
Didinium nasutum
Much of what has been published about this genus is based on numerous studies of a single species, Didinium nasutum. A voracious predator, D. nasutum uses specialized structures called toxicysts to ensnare and paralyze its ciliate prey. Once captured, the prey is engulfed by Didinium's expandible cytostome.[9]
While D. nasutum is sometimes described as feeding exclusively upon Paramecium, it has been shown that the organism will readily devour other ciliate species, including Colpoda, Colpidium campylum, Tetrahymena pyriformis, Coleps hirtus, and Lacrymaria olor.[1][10] Moreover, strains of Didinium raised on a Colpidium campylum will actually show a preference for a diet made up of that species, as well as a diminished ability to kill and ingest Paramecia.[1]
In the absence of food, D. nasutum will encyst, lying dormant within a protective coating.[11] In the laboratory, other environmental stimuli, such as the age of the growth medium or the accumulation of certain metabolic waste products, can also trigger encystment.[12] When the encysted form of D. nasutum is exposed to a vigorous culture of Paramecium, it will excyst, reverting to its active, swimming form.[13]
Didinium cysts have been shown to remain viable for at least 10 years.[14]
History and classification
In the 18th century, Didinium was discovered by the naturalist
Genetic analysis of Haptorian ciliates has shown that they do not form a monophyletic group.[19][20]
List of Species
Didinium armatum Penard, 1922
Didinium balbianii Fabre-Domergue, 1888
Didinium bosphoricum Hovasse, 1932
Didinium chlorelligerum Kahl, 1935
Didinium faurei Kahl, 1930
Didinium gargantua Meunier, 1910
Didinium impressum Kahl, 1926
Didinium minimum
Didinium nasutum (Müller, 1773) Stein, 1859
References
- ^ JSTOR 3225898.
- ^ Kypke, Reinhard. "Didinium gargantua Meunier, 1910". www.zooplankton.cn. Archived from the original on 2016-12-21. Retrieved 2016-12-13.
- ^ Kahl, Alfred (1930–35). F. Dahl (ed.). Urtiere oder Protozoa I: Wimpertiere oder Ciliata (Infusoria) In: Die Tierwelt Deutschlands. Vol. 1. Allgemeiner teil und Prostomata. Jena: G. Fischer. pp. 123–6.
- ^ "Didinium Morphology". www.nies.go.jp. Retrieved 25 October 2019.
- ISBN 1-891276-22-0.
- ^ Mast 1909, pp. 92–3
- ^ Mast 1909, p. 92
- ^ Kent, William Saville (1881–1882). A Manual of the Infusoria. Vol. 2. London: David Bogue. pp. 638–9.
- ^ Mast 1909, pp. 96–112
- ^ Mast 1909, p. 114
- PMID 16576909.
- S2CID 83902868.
- .
- S2CID 83784747.
- ^ Müller, O.F. Animalcula Infusoria, Fluvia Tilia et Marina. 1786. Hauniae, Typis N. Mölleri. pp. 268-9.
- ^ Stein, Friedrich (1859). Der Organismus der Infusionsthiere (1859). Leipzig: W. Engelmann.
- ^ Bütschli, Otto (1887–1889). Bronn, H. G. (ed.). ERSTER BAND. PROTOZOA. Vol. III. Leipzig & Heidelberg: C. F. Winter. p. 1688.
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ignored (help) - .
- S2CID 41417127.
- PMID 21333743.
- Mast, S. O. (February 1909). "The Reactions of Didinium nasutum (Stein) with Special Reference to the Feeding Habits and the Function of Trichocysts". Biological Bulletin. 16 (3): 91–118. JSTOR 1536126.