Alexandrium tamarense: Difference between revisions

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Like other dinoflagellate species, ''A. tamarense'' propels itself through water using two flagella in a whip-like fashion. It is also considered "armored" because it is surrounded by a layer of cellulose that form plates known as thecae.
Like some other dinoflagellate species, ''A. tamarense'' is photoautotrophic and obtains it manufactures its own food by using energy is obtains from sunlight. It is considered a primary producer and is a source of food for many othe organisms.
 
''A. tamarense'' is also motile, having two flagella which it uses to propel itself through water.  
 
It is also considered "armored" because it is surrounded by a layer of cellulose that form plates known as thecae.


==Ecology==
==Ecology==

Revision as of 08:24, 1 April 2008

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Classification

Alexandrium tamarense.jpg Alexandrium tamarense2.gif

Picture courtesy of USGS Woods Hole Science Center

Higher order taxa

Domain: Eukaryota

Phylum: Alveolata

Class: Dinophyceae

Order: Gonyaulacales

Family: Gonyaulacaceae

Species

Alexandrium tamarense

Synonyms: Gonyaulax tamarensis Lebour 1925 , G. excavata (Braarud) Balech 1971 Protogonyaulax tamarensis (Lebour) F. J. R. Taylor 1979

Description and significance

Describe the appearance, habitat, etc. of the organism, and why it is important enough to have its genome sequenced. Describe how and where it was isolated.


Alexandrium tamarense is a single-celled dinoflagellate found in coastal marine environments throughout the world and is the cause of algal blooms that result in the phenomenon known as red tides.

At only 25-46 micrometers in length per cell A. tamarense is microscopic in size and is brown and circular in appearance. However, blooms of millions of cells per liter of seawater are evident in red tides (pictured below).

260px-La-Jolla-Red-Tide 780.jpg

A. tamarense can be highly toxic to humans as well as other organisms such as marine mammals, birds, and fish. This has led scientists to....

Genome structure

Describe the size and content of the genome. How many chromosomes? Circular or linear? Other interesting features?Does it have any plasmids? Are they important to the organism's lifestyle?


Like other dinoflagellates, Alexandrium tamarense consists of large amounts of DNA compared to other eukaryotic organisms. It consists of 144 chromosomes which are condensed in the nucleus until DNA replication. A total of 11,103 nucleotides [218 nucleotide core and 10,885 expressed sequence tags (ESTs)] have been sequenced.

It is still not clear which genes play a role in toxin production.

Cell structure and metabolism

Describe any interesting features and/or cell structures; how it gains energy; what important molecules it produces.


Like some other dinoflagellate species, A. tamarense is photoautotrophic and obtains it manufactures its own food by using energy is obtains from sunlight. It is considered a primary producer and is a source of food for many othe organisms.

A. tamarense is also motile, having two flagella which it uses to propel itself through water.

It is also considered "armored" because it is surrounded by a layer of cellulose that form plates known as thecae.

Ecology

Describe any interactions with other organisms (included eukaryotes), contributions to the environment, effect on environment, etc.

Pathology

How does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.

Not all strains of Alexandrium tamarense are toxic. Different strains are often found in the same algal blooms caused by this species.

However, some strains of Alexandrium tamarense produce very potent neurotoxins known as paralytic shellfish toxins (PSTs). These toxins, which include gonyautoxins, neosaxitoxin and saxitoxin, affect fish, marine mammals, birds, and humans.

Many deaths have been reported from the consumption of shellfish infected with these toxins.


Resting cysts can harbour PSP toxins, it was been demonstrated that cysts were more toxic than their motile stage. Humans, other mammals, fish and birds can be affected. Please consult original reference for further details. Harmful species http://www.algaebase.org/search/species/detail/?species_id=40299


http://www.nmnh.si.edu/botany/projects/dinoflag/Taxa/Atamarense.htm

Application to Biotechnology

Does this organism produce any useful compounds or enzymes? What are they and how are they used?

Current Research

Enter summaries of the most recent research here--at least three required

References

Don Anderson WHOI, Brad Butman USGS, Peter Franks SIO, Rocky Geyer WHOI, Ted Loder UNH, Rich Signell USGS, Bruce Keafer WHOI, Derek Fong WHOI, "Toxic "Red Tide" Populations in the Western Gulf of Maine: Sources, Transport, and Nutrient Environment

[Sample reference] Takai, K., Sugai, A., Itoh, T., and Horikoshi, K. "Palaeococcus ferrophilus gen. nov., sp. nov., a barophilic, hyperthermophilic archaeon from a deep-sea hydrothermal vent chimney". International Journal of Systematic and Evolutionary Microbiology. 2000. Volume 50. p. 489-500.

"Taxonomy Browser, NCBI"

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