154,918 species and infraspecific names are in the database, 21,111 images, 59,859 bibliographic items, 429,125 distributional records.

Prototheca W.Krüger, 1894

Empire Eukaryota
Kingdom Plantae
Subkingdom Viridiplantae
Infrakingdom Chlorophyta infrakingdom
Phylum Chlorophyta
Subphylum Chlorophytina
Class Trebouxiophyceae
Order Chlorellales
Family Chlorellaceae

Lectotype species: Prototheca zopfii W.Krüger

Original publication:Krüger, W. (1894). Kurze Charakteristik einiger niedrerer Organismen im Saftfluss der Laubbäume. Hedwigia 33: 241-266.
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Type designated in Negroni, P. & Blaisten, R. (1941). Estudio morfologico y fisiologico de una especie de Prototheca: Prototheca ciferri n. sp., aislada de epidermis de papa. Mycopathologia 35: 94-104.

Taxonomic status: currently recognized as a distinct genus.

Taxonomic notes
Ueno et al. (2005) propose restricting the genus Prototheca to the four species: P. moriformis Krüger, P. stagnora (Cooke) Pore, P. ulmea Pore and P. zopfii Krüger. - (8 Aug 2011) - Wendy Guiry

Description: Unicellular microscopic thalli becoming aggregated in culture when grown on solid substrates. Cells round to ellipsoid 5-40 µm in maximum dimension. Cell walls smooth with an inner polysaccharide layer and an outer trilamellate region. Cells colorless and apochlorotic, without chloroplasts and pyrenoids, but with stored starch. Asexual reproduction by spherical to ellipsoid aplanospores (also referred to as "endospores"), 2-16 per sporangium; released by rupture of parental cell wall. Hypnospores reported for one species. Flagellated stages and sexual reproduction unknown.

Information contributed by: T. Kalina, D. Garbary & M.D. Guiry. The most recent alteration to this page was made on 25 Aug 2014 by M.D. Guiry.

Comments: Prototheca widely distributed from temperate to tropical conditions in both fresh and marine waters; isolated internally and externally from humans. Prototheca the only known alga which is a disease causing organism in humans; associated with conditions termed protothecosis. Several clinical forms are recognized including skin lesions and bursitis. Pathology associated with P. wickerhamii and P. zopfii. Genus considered close to Chlorella complex. Prototheca has similar bilayered wall structure to genera in Scotiellocystoideae and may be associated with this subfamily; cell walls with resistant polymer consisting of terpenoid units, but with different structure from classical sporopollenin. 18S rRNA sequence studies confirm suggest a close affinity with Auxenochlorella. Species distinguished based on ability to assimilate various organic compounds, and cell size and shape. Ueno et al. (2005) proposed restricting the genus to species incapable of growing on trehalose, and recommend the retenion of four species: P. moriformis, P. stagnora, P. ulmea and P. zopfii.

Numbers of names and species: There are 18 species names in the database at present, as well as 4 infraspecific names. Of the species names, 14 have been flagged as accepted taxonomically on the basis of the listed literature under the species name. In some instances, opinions on taxonomic validity differ from author to author and users are encouraged to form their own opinion. AlgaeBase is a work in progress and should not be regarded as a definitive source only as a guide to the literature..

Names: ('C' indicates a name that is accepted taxonomically; 'S' a homotypic or heterotypic synonym; 'U' indicates a name of uncertain taxonomic status, but which has been subjected to some verification nomenclaturally; 'P' indicates a preliminary AlgaeBase entry that has not been subjected to any kind of verification. For more information on a species click on it to activate a link to the Species database):

Click here to also show infraspecific names in the list below.

Ueno, R., Hanagata, N., Urano, N. & Suzuki, M. (2005). Molecular phylogeny and phenotypic variation in the heterotrophic green algal genus Prototheca (Trebouxiophyceae, Chlorophyta). Journal of Phycology 41: 1268-1280.

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Some of the descriptions included in AlgaeBase were originally from the unpublished Encyclopedia of Algal Genera, organised in the 1990s by Dr Bruce Parker on behalf of the Phycological Society of America (PSA) and intended to be published in CD format. These AlgaeBase descriptions are now being continually updated, and each current contributor is identified above. The PSA and AlgaeBase warmly acknowledge the generosity of all past and present contributors and particularly the work of Dr Parker.

Descriptions of chrysophyte genera were subsequently published in J. Kristiansen & H.R. Preisig (eds.). 2001. Encyclopedia of Chrysophyte Genera. Bibliotheca Phycologica 110: 1-260.

Created: 17 August 2004 by M.D. Guiry

Verified by: 25 August 2014 by M.D. Guiry

Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=44581

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M.D. Guiry in Guiry, M.D. & Guiry, G.M. 2019. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 21 March 2019.

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