Porphyridium Nägeli, 1849, nom. cons.
Holotype species: Porphyridium cruentum (S.F.Gray) Nägeli
Currently accepted name for the type species: Porphyridium purpureum (Bory) K.M.Drew & R.Ross
Original publication and holotype designation: Nägeli, C. (1849). Gattungen einzelliger Algen, physiologisch und systematisch bearbeitet. Neue Denkschriften der Allg. Schweizerischen Gesellschaft für die Gesammten Naturwissenschaften 10(7): i-viii, 1-139, pls I-VIII.
Description: Spherical to obovoid unicells with stellate chloroplast and prominent central pyrenoid. Cell diam. 5-10 µm in exponential, 7-16 µm in stationary phase. Cells solitary, but often grouped into irregular colonies with ill-defined mucilaginous matrix. Species distinguished by chloroplast color. Ultrastructure well studied. Other organelles restricted to small fraction of cytoplasm peripheral to chloroplast. Thylakoids single with no peripheral, encircling one. During mitosis, nuclear envelope persists but polar gaps develop by metaphase. Nuclear-associated organelle large oblong "granule" with small discoid portion. Are chromosomal and non-chromosomal microtubules. Cytokinesis by cleavage furrow through chloroplast. Cells move on agar with large vesicles in posterior end containing fibrillar material similar to sheath. Stationary-phase cells have reduced chloroplast, abundant starch, lipid globules and thick fibrillar walls.
Information contributed by: R.G. Sheath. The most recent alteration to this page was made on 2022-03-30 by M.D. Guiry.
Taxonomic status: This name is of an entity that is currently accepted taxonomically.
Gender: This genus name is currently treated as neuter.
Most recent taxonomic treatment adopted: Necchi, O., Jr. & Vis, M.L. (2021). Subphylum Cyanidiophytina, Class Cyanidiophyceae; Subphylum Proteorhodophytina, Classes Compsopogonophyceae, Porphyridiophyceae, Rhodellophyceae, and Stylonematophyceae. In: Freshwater red algae Phylogeny, taxonomy and biogeography. ( Eds), pp. 27-56. Cham: Springer [Springer Nature Switzerland AG].
Comments: Popular genus for biochemical and physiological studies. Major monomeric units in mucilage D-xylose, D-glucuronic acid, D-glucose and galactose. P. aerugineum contains C-phycocyanin (PC) and allophycocyanin (APC); P. purpureum phycoerythrin (PE), b-Pe, R-PC and APC. Phycobilisomes well characterized. In cultures of P. purpureum grown under optimal conditions, eicosapentaenoic acid main polyunsaturated fatty acid; stressed cells accumulate arachidonic acid. ADPG transferase may be controlling enzyme in floridean starch synthesis. Cells can become dormant during prolonged darkness. Species vary in tolerance of salinity fluctuations. Forms gelatinous coatings on surfaces in freshwaters, brackish and marine environments and moist soils. P. aerugineum mostly freshwater; P. purpureum grows well in seawater.
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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.
Linking to this page: https://www.algaebase.org/search/genus/detail/?genus_id=33123
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 30 March 2022. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 04 December 2023