Noctiluca scintillans: Difference between revisions

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{{Taxobox
| color = aqua
| name = ''Noctiluca scintillans''
| image = Noctiluca scintillans varias.jpg
| domain = Eukaryota
| phylum = Dinoflagellata
| class = Noctiluciphyceae
| order =  Noctilucales
| family = Noctilucaceae
| genus =  Noctiluca
| species = ''N.scintillans''
| binomial name = ''Noctiluca scintillans''
| binomial_authority =
}}
==Description and Significance==
''Noctiluca scintillans'', also known as the sea sparkle, is a single-celled dinoflagellate that exhibits bioluminescence.  They are free-living marine plankton, which range between 200-2000 micrometers in diameter.  They are found mostly in estuaries and other coastal regions and can be found in both warm and cold waters. ''N. scintillans'' are heterotrophic and non-photosynthetic, meaning they receive their carbon from organic compounds and receive their energy through the ingestion of organic substances. They don’t have any chloroplasts so, their cytoplasm is relatively clear. ''Noctiluca scintillans'' are non-motile, even though they possess a flagellum, and only move vertically by changing their buoyancy using gas vacuoles. ''N. scintillans'' can reproduce asexually, by binary fission, and sexually, using isogametes through a diplontic lifecycle.
The bioluminescent property of ''N. scintillans'' is a tourist attraction for many countries throughout the world. People would take boat rides and watch these dinoflagellates emit flashes of blue light when disturbed, giving them the name sea sparkle.
==Genome and Structure==
Many studies have been done on the luciferase gene within the scintillons of ''N. scintillans''.  They have found that ''N. scintillans'' is genetically distinct from the other six bioluminescent dinoflagellates that have been studied, because the N-terminus is missing a ~100aa sequence.  Still the N-terminus is closely related to the other bioluminescent dinoflagellates.  The C-terminal end of this gene, however, is closely related to a separate gene in a photosynthetic dinoflagellate.  It is as if these two genes in the photosynthetic species were fused in ''N. scintillans''.  Studies of the 18S ribosomal DNA of ''N. scintillans'', also suggested that they were one of the first species to branch off because their genomic sequence is most closely related to the ancestral gene.
==Cell Structure and Metabolism==
''N. scintillans'' has a round, balloon-like, body shape and is unarmored, meaning it does not have a protective shell. Since they do not photosynthesize they do not contain chloroplasts, and thus are fairly clear. The red and green color usually associated with this species during red and green tides, are due to the pigments of the photosynthetic symbionts within the vacuoles of ''N. scintillans'' and not the species itself. ''N. scintillans'' has a ventral groove that runs through it's body which contains the flagellum, a tooth and a tentacle. They also have a mouth-like structure called the cytostome, which is used to capture and consume prey.
''N. scintillans'' is a phagotrophic species with many food vacuoles found throughout it's cytoplasm. They engulf smaller marine species such as diatoms, protozoans, fish eggs, and certain bacteria, and then digest them in these food vacuoles. ''N. scintillans'' also contains gas vacuoles, which are filled with ammonia gas, that allow them to control their buoyancy.
Small cytoplasmic bodies within the cells, called scintillons, are what give ''N. scintillans'' their bioluminescent property. Luciferase and luciferin are both found in those structures and it is the interaction of both these molecules that emits light.
==Bioluminescence==
[[Image:noctilucapic2.jpg|right|300 px|citi key logo]]
N. scintillans may use bioluminescence for many different purposes.  It could be used as a defense against predators, an offensive strategy to keep away other predators from their prey, or as a means of communication.  They emit light on a circadian rhythm and when they are disturbed as a flash of bright blue light for no more than a second.  Light is emitted when luciferin, which is an open-chain tetrapyrrole in dinoflagellates and believed to be derived from chlorophyll, becomes oxidized by molecular oxygen, with the help of the catalyst luciferase.  This process is called chemiluminescence because it is the convergence of chemical energy into light energy.
==Ecology and Pathology==
==Ecology and Pathology==


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''N. scintillans'' are sometimes known to have a large population boom known as red or green tides (depending on what color endosymbionts are present in their vacuoles.) These tides cause the death of many marine animals. ''N. scintillans'' does not, however, release exotoxins like many other dinoflagellates do.  Instead, it is believed that they kill these animals by suffocation due to the release of ammonia and carbon dioxide, causing anoxic water conditions.
''N. scintillans'' are sometimes known to have a large population boom known as red or green tides (depending on what color endosymbionts are present in their vacuoles.) These tides cause the death of many marine animals. ''N. scintillans'' does not, however, release exotoxins like many other dinoflagellates do.  Instead, it is believed that they kill these animals by suffocation due to the release of ammonia and carbon dioxide, causing anoxic water conditions.
==Current Research==
'''Ride Tide of Noctiluca Scintillans and it's Impact on the Coastal Water Quality of the Near-Shore'''
'''Waters, Off the Rushikulya River, Bay of Bengal'''
This study is being conducted to check the quality of the water after red tides of N. scintillans.  The researchers take samples of the water from different depths and determine the quality of the water by checking temperature, salinity, nitrate, nitrite and phosphate concentration.
'''Seasonality of the Bloom-Forming Hetertrophic dinoflagellate Noctiluca Scintillans'''
'''in the Gulf of Oman in Relation to Environmental Conditions'''
This study is being conducted to find what environmental factors contribute to the population blooms of Noctiluca Scintillans.  They are checking hydrographic and biological factors as well as other factors such as wind intensity.
==References==
Noctiluca : Sparkle of the sea.  1995. Microscopy-UK.  April 2009. http://www.microscopy-
uk.org.uk/mag/indexmag.html?http://www.microscopy-uk.org.uk/mag/art98/nocti.html
Identifying Harmful Marine Dinoflagellates.  Smithsonian National Museum of Natural History Botany
Department.  April 2009. http://botany.si.edu/references/dinoflag/Taxa/Nscintillans.htm
Nakamura, Yasuro.  "Biomass, feeding and production of Noctiluca scintillans in the Seto Inland Sea,
Japan."  Journal of Plankton Research.  20.11 (1998): 2213-2222
Noyan Yilmaz, Erdoğan Okus¸ and Ahsen Yüksek.  "Evidences for influence of a heterotrophic
dinoflagellate (Noctiluca scintillans) on zooplankton community structure in a highly stratified
basin."  Estuarine, Coastal, and Shelf Science. 64.2-3 (2005): 475-485
"Ride Tide of Noctiluca Scintillans and it's Impact on the Coastal Water Quality of the Near-Shore
Waters, Off the Rushikulya River, Bay of Bengal."  Current Science. 93.5 (2007): 616-617
Al-Azri, Adnan. "Seasonality of the Bloom-Forming Hetertrophic dinoflagellate Noctiluca Scintillans
in the Gulf of Oman in Relation to Environmental Conditions."  International Journal of Oceans and
Oceanography. 2.1 (2007): 51-60
Liu, Liyun.  "Two Different Domains of the Luciferase Gene in the Heterotrophic Dinoflagellate
Noctiluca Scintillans Occur as Two Separate Genes in Photosynthetic Species." PNAS.  104.3 (2007):
696-701
Hoppenrath, Mona and Juan F. Saldarriaga. 2008. Dinoflagellates. Version 16 September 2008 (under
construction). http://tolweb.org/Dinoflagellates/2445/2008.09.16 in The Tree of Life Web Project,
http://tolweb.org/
Asare, Amma.  Bioluminescence.  Milton Academics Marine Biology Department.
http://www.milton.edu/academics/pages/marinebio/biolum.html
J. Woodland Hastings. Luciferase and Light-emitting Accessory Proteins: Structural Biology. Encyclopedia of Life Sciences.

Revision as of 17:05, 9 May 2009

Ecology and Pathology

N. scintillans are found mostly in coastal areas, in both temperate and tropical waters. Their population density has been found to be dependent on food availability, which is why they tend to stay in shallow, coastal areas, where phytoplankton thrive. They are also a major factor on the population density of zooplankton.

N. scintillans are sometimes known to have a large population boom known as red or green tides (depending on what color endosymbionts are present in their vacuoles.) These tides cause the death of many marine animals. N. scintillans does not, however, release exotoxins like many other dinoflagellates do. Instead, it is believed that they kill these animals by suffocation due to the release of ammonia and carbon dioxide, causing anoxic water conditions.

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