Cladus: Eukaryota
Regnum: Plantae
Divisio: Chlorophyta
Classis: Prasinophyceae
Ordo: Chlorodendrales - Dunalliellales - Halosphaerales - Mamiellales
Name
Prasinophyceae T. Christensen ex P.C. Silva
Vernacular names
Internationalization
日本語: プラシノ藻綱
In taxonomy, Prasinophytes are a class of the Division Chlorophyta. These are primitive eukaryotic, marine green algae.[2] Its best known genus is Ostreococcus (seen at right), which is considered to be the smallest (ca. 0.95 μm) free-living eukaryote[3] and which has been detected in marine samples around the world. Prasinophytes are thought to have low cellular complexity, that is, they are naked cells that possess single, multiple or no flagellae and contain only a single chloroplast and a single mitochondrion. They also have very small genomes for a eukaryote (about 12Mbp).
It has been suggested that a prasinophyte-like flagellate was the ancestor to Chlorophyta and Streptophyta.[4]
Ecology
A study of photosynthetic gene-sequence diversity (rbcL) in the Gulf of Mexico indicated that Prasinophytes are particularly prevalent at the Subsurface Chlorophyll Maximum (SCM)[5] and several different ecotypes of Ostreococcus have been detected in the environment.[6] These ecotypes are distinguished by their adaptation to light intensities. O. lucimarinus is found in high-light environments and represents surface-isolated strains. RCC141 is considered low-light, because these strains were isolated from the lower euphotic zone. O. tauri was isolated from a coastal lagoon and is considered light-polyvalent. Genetic data indicates that distinct molecular differences exist between the different ecotypes that have been detected.[7]
References
1. ^ Guiry, M.D. & Guiry, G.M. (2007). "Class: Prasinophyceae taxonomy browser". AlgaeBase version 4.2 World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org/browse/taxonomy/?id=4345. Retrieved 2007-09-23.
2. ^ Sym SD, Pienaar RN (1993). "The class Prasinophyceae". Prog Phycol Res 9: 281–376.
3. ^ Courties C, Vaquer A, Troussellier M, Lautier J, Chrétiennot-Dinet MJ, Neveux J, Machado C, Claustre H (1994). "Smallest eukaryotic organism". Nature 370: 255. doi:10.1038/370255a0.
4. ^ Kapraun DF (April 2007). "Nuclear DNA content estimates in green algal lineages: chlorophyta and streptophyta". Ann. Bot. 99 (4): 677–701. doi:10.1093/aob/mcl294. PMC 2802934. PMID 17272304. http://aob.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=17272304.
5. ^ Wawrik B, Paul JH, Campbell L, Griffin D, Houchin L, Fuentes-Ortega A, Müller-Karger F (2003). "Vertical Structure of the Phytoplankton Community Associated with a Coastal Plume in the Gulf of Mexico". Marine Ecology Progress Series 251: 87–101. doi:10.3354/meps251087.
6. ^ Guillou L, Eikrem W, Chrétiennot-Dinnet MJ, Le Gall F, Massana R, Romari K, Pedros-Alio C, Vaulot D (2004). "Diversity of picoplanktonic Prasinophyceae assessed by direct SSU rDNA sequencing of environmental samples and novel isolates retrieved from oceanic and coastal marine ecosystems". Protist 155: 193–214. doi:10.1078/143446104774199592.
7. ^ Rodríguez F, Derelle E, Guillou L, Le Gall F, Vaulot D, Moreau H (2005). "Ecotype diversity in the marine picoeukaryote Ostreococcus (Chlorophyta, Prasinophyceae)". Environmental Microbiology 7 (6): 853–859. doi:10.1111/j.1462-2920.2005.00758.x. PMID 15892704.
