''Phaeodactylum tricornutum'' is a

diatom A diatom ( Neo-Latin ''diatoma''), "a cutting through, a severance", from el, διάτομος, diátomos, "cut in half, divided equally" from el, διατέμνω, diatémno, "to cut in twain". is any member of a large group comprising se ...

. It is the only species in the genus ''Phaeodactylum''. Unlike other diatoms, ''P. tricornutum'' can exist in different morphotypes (

fusiform Fusiform means having a spindle-like shape that is wide in the middle and tapers at both ends. It is similar to the lemon-shape, but often implies a focal broadening of a structure that continues from one or both ends, such as an aneurysm on a ...

, triradiate, and oval) and changes in cell shape can be stimulated by environmental conditions. This feature can be used to explore the molecular basis of cell shape control and morphogenesis. Unlike most diatoms, ''P. tricornutum'' can grow in the absence of silicon and can survive without making silicified frustules. This provides opportunities for experimental exploration of silicon-based nanofabrication in diatoms. Another peculiarity is that during asexual reproduction the

frustule A frustule is the hard and porous cell wall or external layer of diatoms. The frustule is composed almost purely of silica, made from silicic acid, and is coated with a layer of organic substance, which was referred to in the early literature on d ...

s do not appear to become smaller. This allows continuous culture without need for sexual reproduction. It is not known if ''P. tricornutum'' can reproduce sexually. To date no substantial evidence has been found to support sexual reproduction in a laboratory or other setting. Although ''P. tricornutum'' can be considered to be an atypical pennate diatom, it is one of the main diatom model species. A transformation protocol has been established and RNAi vectors are available. This makes molecular genetic studies much easier.

History

''Phaeodactylum tricornutum'' was first described in the triradiate morphotype by Bohlin in 1897. Recordings of the first cultures of ''P. tricornutum'' were published by Allen and Nelson in 1910, although it was misidentified as ''Nitzschia colsterium,W. Sm., forma miuntissima''. The isolate was later correctly revised as ''P. tricorntum'' by J.C. Lewin in 1958. This strain among other later isolates are still maintained in culture collections around the world.

Genome sequencing

''Phaeodactylum tricornutum'' is one of three diatoms whose

genome In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding gen ...

has been sequenced (the others being ''

Thalassiosira pseudonana ''Thalassiosira pseudonana'' is a species of marine centric diatoms. It was chosen as the first eukaryotic marine phytoplankton for whole genome sequencing. ''T. pseudonana'' was selected for this study because it is a model for diatom physiolog ...

'' and '' Fragilariopsis cylindrus''). The genome contains approximately 10% prokaryote-like genes, an unusually large proportion. Over 30000 expressed sequence tags (ESTs) have been organized into the Diatom EST Database. ''Phaeodactylum tricornutum'' has emerged as a potential microalgal energy source. It grows rapidly and storage lipids constitute about 20-30% of its dry cell weight under standard culture conditions. Nitrogen limitation can induce neutral lipid accumulation in ''P. tricornutum'', indicating possible strategies for improving microalgal biodiesel production .

References

External links

*
journals.tubitak.gov.tr
The Growth of Continuous Cultures of the Phytoplankton Phaeodactylum Tricornutum (pdf)

picture of phaeodactylum tricornutum {{DEFAULTSORT:Phaeodactylum Tricornutum High lipid content microalgae Naviculales

History

Genome sequencing

See also

References

External links