Nassula

Nassula is a genus of unicellular ciliates, belonging to the class Nassophorea. Like other members of the class, Nassula possesses a basket-like feeding apparatus (nasse, or cyrtos) made up of cytopharyngeal rods (nematodesmata), which are themselves composed of closely packed microtubules.[1][2][3] Nassula use this structure to ingest filamentous cyanobacteria, drawing individual strands of blue-green algae through the cytopharynx and into the body of the cell, where they are digested. As the algae are broken down, they can take on a variety of bright colours, which give Nassula a distinctive, variegated appearance under the microscope.

Nassula
Nassula sp.
Scientific classification
Domain:
Eukaryota
(unranked):
Sar
(unranked):
Alveolata
Phylum:
Ciliophora
Subphylum:
Intramacronucleata
Class:
Nassophorea
Order:
Nassulida
Family:
Nassulidae
Genus:
Nassula

Ehrenberg, 1833

Description

The body is ovoid to elongate, and uniformly ciliated, with a single macronucleus and a partial hypostomial frange (synhymenium) running from the left side of the cell to the oral aperture.[4] When food is scarce, members of the genus have the ability to become dormant by forming a microbial cyst. Excystment can be induced by exposure to a medium inoculated with wild bacteria.[5]

Reproduction

Nassula reproduce asexually, by fission.[6] During reproduction, the cell is divided transversally. As in most ciliates (with the exception of the Karyorelictea) the macronucleus splits, during division, and the micronuclei also undergo mitosis.

While fission is an asexual process, it may be preceded by conjugation, during which compatible mating individuals come together and transfer genetic material across a cytoplasmic link. In conjugation, the micronuclei of each cell undergo meiosis, and haploid micronuclei are then exchanged from one cell to the other. After sexual exchange has occurred, both conjugants will divide by fission.[7]

Species list
  • Nassula ambigua Stein, 1854
  • Nassula argentula Kahl, 1930
  • Nassula aureola
  • Nassula carpathica Lepsi, 1927
  • Nassula caudata Ozaki & Yagiu, 1941
  • Nassula citrea Kahl, 1931
  • Nassula concinna Perty, 1852
  • Nassula conica
  • Nassula dentata (Dujardin, 1841) Fromentel, 1876
  • Nassula depressa
  • Nassula derouxi Njine 1979
  • Nassula discoidea Dumas, 1929
  • Nassula dragescoi Foissner, Agatha & Berger, 2002
  • Nassula elongata Dumas, 1930
  • Nassula enormis
  • Nassula etoschensis Foissner, Agatha & Berger, 2002
  • Nassula euglena Dingfelder, 1962
  • Nassula exigua Kahl, 1931
  • Nassula flava Claparède & Lachmann, 1859
  • Nassula gigantea Bullington, 1940
  • Nassula gigas
  • Nassula granata Foissner, Agatha & Berger, 2002
  • Nassula gutturata Gajewskaja, 1927
  • Nassula halophila Gurwitsch, 1934
  • Nassula hesperidae Entz, 1884
  • Nassula lateritia Claparède & Lachmann, 1859
  • Nassula leucas
  • Nassula longinassa Foissner, 1979
  • Nassula longissima Ozaki & Yagiu, 1941
  • Nassula magna Smith, 1897
  • Nassula microstoma Calkins, 1903
  • Nassula microstoma Cohn, 1866
  • Nassula microstomata
  • Nassula minima Minkiewicz, 1899
  • Nassula muscicola Kahl, 1931
  • Nassula nahchivanica Alekperov, 1984
  • Nassula notata Müller, 1786
  • Nassula oblonga Maupas, 1883
  • Nassula ornata Ehrenberg, 1834
  • Nassula parva Kahl, 1928
  • Nassula plantiformis
  • Nassula pluvialis Dingfelder, 1962
  • Nassula pseudonassula Penard, 1922
  • Nassula pusilla Kahl, 1931
  • Nassula renalis Ozaki & Yagiu, 1941
  • Nassula rostrata Dumas, 1930
  • Nassula rotunda Gelei, 1950
  • Nassula rubescens Dumas, 1930
  • Nassula terminalis Ozaki & Yagiu, 1941
  • Nassula terricola Foissner, 1989
  • Nassula transpeisonica Löffler, 1979
  • Nassula tuberculata Foissner, Agatha & Berger, 2002
  • Nassula tumida Maskell, 1887
  • Nassula versicolor André, 1916
  • Nassula vesiculosaGajewskaja, 1933

References
  1. Tucker JB (December 1968). "Fine structure and function of the cytopharyngeal basket in the ciliate Nassula". Journal of Cell Science. 3 (4): 493–514. doi:10.1242/jcs.3.4.493. PMID 4974275.
  2. Tucker JB (March 1970). "Morphogenesis of a large microtubular organelle and its association with basal bodies in the ciliate Nassula". Journal of Cell Science. 6 (2): 385–429. doi:10.1242/jcs.6.2.385. PMID 4986841.
  3. Vigues, Bernard; Blanchard, Marie-Pierre; Bouchard, Philippe (1999). "Centrin-like filaments in the cytopharyngeal apparatus of the ciliates Nassula and Furgasonia: evidence for a relationship with microtubular structures". Cell Motility and the Cytoskeleton. 43 (1): 72–81. doi:10.1002/(SICI)1097-0169(1999)43:1<72::AID-CM8>3.0.CO;2-U. PMID 10340705.
  4. Carey, Phillip G. (1992). Marine Interstitial Ciliates: An Illustrated Key. Chapman and Hall. p. 112. ISBN 978-0-412-40610-2.
  5. Beers CD (February 1966). "The excystment process in the ciliate Nassula ornata Ehrbg". The Journal of Protozoology. 13 (1): 79–83. doi:10.1111/j.1550-7408.1966.tb01874.x. PMID 4958004.
  6. Tucker JB (December 1967). "Changes in nuclear structure during binary fission in the ciliate Nassula". Journal of Cell Science. 2 (4): 481–98. doi:10.1242/jcs.2.4.481. PMID 4965925.
  7. The Ciliated Protozoa - Characterization, Classification, and Guide to the | Springer. Springer. 2008. p. 23. ISBN 9781402082382.
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