Prasinococcus capsulatus
Encyclopedia
In taxonomy
, Prasinococcus capulatus is a species of algae
, specifically of the Prasinococcus
. The name "'capulatus'" coming from the alga's large capsule which surrounds the cell. This unicellular algal species was discovered in 1990 in the West Pacific Ocean
and has characteristic reproduction methods as well as an interesting and potentially exploitable morphology. This is the only species in the genus, though various strains exist, for example URI 266G is the Atlantic clone.
which has been dubbed "capsulan
". Capsulan is thought to be synthesised in the Golgi
and then secreted through the decapore (a specialised circle of 10 pores through the cell wall
). After exiting the decapore capsulan becomes visible and it is thought that it cross links with divalent
ions in the seawater. Research is currently underway to find potential applications for capsulan and how to maximise its production.
The capsule's function is not clearly defined but various explanations have been suggested. One is that it offers protection to newly divided cells which lack a thick cell wall, another is that it provides a template for daughter cells to synthesise their new cell wall. The capsule may also interfere with filter feeding, thus reducing predation. In similar species, capsules have been noted for their antibacterial properties and a conspicuous lack of bacteria as well as viral particles in impure samples of P. capsulatus has been observed.
has not been observed in P. capsulatus but its mode of asexual reproduction is quite distinctive. The cell splits into two daughter
cells while remaining inside the original cell wall, one daughter cell then begins to enlarge, while the other is pushed out of a small hole in the parental cell wall. The larger cell remains in the original cell wall while the other migrates to the edge of the capsule which surrounds them both. Before leaving the parental capsule this daughter has synthesised its own firm cell wall after which it leaves the parental capsule and begins to produce its own capsule.
Others claim that this mode of reproduction immature cells with thinner walls older cells with thicker walls must first discard the paternal cell wall before undergoing binary fission and then each daughter cell produces its own new cell wall. This is evidenced by abandoned cell walls residing in mature cells' capsules.
especially in late winter to early spring. Its range covers much of the West Pacific and West Atlantic Oceans.
capture, especially important as it recycles this carbon into capsulan which may be a useful compound.
Alpha taxonomy
Alpha taxonomy is the discipline concerned with finding, describing and naming species of living or fossil organisms. This field is supported by institutions holding collections of these organisms, with relevant data, carefully curated: such institutes include natural history museums, herbaria and...
, Prasinococcus capulatus is a species of algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
, specifically of the Prasinococcus
Prasinococcus
In taxonomy, Prasinococcus is a genus of algae, specifically of the Pycnococcaceae. -Discovery:Prasinococcus capsulatus, the only currently known member of this genus, was discovered in the West Pacific Ocean during a cruise by the research vessel Sohgen-maru in November-December 1990...
. The name "'capulatus'" coming from the alga's large capsule which surrounds the cell. This unicellular algal species was discovered in 1990 in the West Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
and has characteristic reproduction methods as well as an interesting and potentially exploitable morphology. This is the only species in the genus, though various strains exist, for example URI 266G is the Atlantic clone.
Morphology
The most notable feature of P. capsulatus's morphology is its large capsule composed of an exo-polysaccharidePolysaccharide
Polysaccharides are long carbohydrate molecules, of repeated monomer units joined together by glycosidic bonds. They range in structure from linear to highly branched. Polysaccharides are often quite heterogeneous, containing slight modifications of the repeating unit. Depending on the structure,...
which has been dubbed "capsulan
Capsulan
Capsulan is the exopolysaccharide which makes up the thick capsule surrounding the unicellular alga Prasinococcus capsulatus. -Extraction:...
". Capsulan is thought to be synthesised in the Golgi
Golgi
Golgi may refer to:*Camillo Golgi , Italian physician and scientist after which the following terms are named:**Golgi apparatus , an organelle in the eukaryotic cell...
and then secreted through the decapore (a specialised circle of 10 pores through the cell wall
Cell wall
The cell wall is the tough, usually flexible but sometimes fairly rigid layer that surrounds some types of cells. It is located outside the cell membrane and provides these cells with structural support and protection, and also acts as a filtering mechanism. A major function of the cell wall is to...
). After exiting the decapore capsulan becomes visible and it is thought that it cross links with divalent
Divalent
In chemistry, a divalent ion or molecule has a valence of two and thus can form two bonds with other ions or molecules. An older term for divalent is bivalent....
ions in the seawater. Research is currently underway to find potential applications for capsulan and how to maximise its production.
The capsule's function is not clearly defined but various explanations have been suggested. One is that it offers protection to newly divided cells which lack a thick cell wall, another is that it provides a template for daughter cells to synthesise their new cell wall. The capsule may also interfere with filter feeding, thus reducing predation. In similar species, capsules have been noted for their antibacterial properties and a conspicuous lack of bacteria as well as viral particles in impure samples of P. capsulatus has been observed.
Reproduction
Sexual reproductionSexual reproduction
Sexual reproduction is the creation of a new organism by combining the genetic material of two organisms. There are two main processes during sexual reproduction; they are: meiosis, involving the halving of the number of chromosomes; and fertilization, involving the fusion of two gametes and the...
has not been observed in P. capsulatus but its mode of asexual reproduction is quite distinctive. The cell splits into two daughter
Daughter
A daughter is a female offspring; a girl, woman, or female animal in relation to her parents. The male equivalent is a son. Analogously the name is used on several areas to show relations between groups or elements.-Etymology:...
cells while remaining inside the original cell wall, one daughter cell then begins to enlarge, while the other is pushed out of a small hole in the parental cell wall. The larger cell remains in the original cell wall while the other migrates to the edge of the capsule which surrounds them both. Before leaving the parental capsule this daughter has synthesised its own firm cell wall after which it leaves the parental capsule and begins to produce its own capsule.
Others claim that this mode of reproduction immature cells with thinner walls older cells with thicker walls must first discard the paternal cell wall before undergoing binary fission and then each daughter cell produces its own new cell wall. This is evidenced by abandoned cell walls residing in mature cells' capsules.
Distribution
P. capsulatus is an important contributor to oceanic biomassBiomass
Biomass, as a renewable energy source, is biological material from living, or recently living organisms. As an energy source, biomass can either be used directly, or converted into other energy products such as biofuel....
especially in late winter to early spring. Its range covers much of the West Pacific and West Atlantic Oceans.
Bio-remediation
P. capsulatus is currently being studied for use in Carbon DioxideCarbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
capture, especially important as it recycles this carbon into capsulan which may be a useful compound.