Epithemia

Epithemia
Epithemia sorex
Scientific classification Edit this classification
Domain: Eukaryota
Clade: Diaphoretickes
Clade: SAR
Clade: Stramenopiles
Phylum: Gyrista
Subphylum: Ochrophytina
Class: Bacillariophyceae
Order: Rhopalodiales
Family: Rhopalodiaceae
Genus: Epithemia
F.T.Kützing, 1844

Epithemia is a genus of diatoms belonging to the family Rhopalodiaceae.[1] The genus has cosmopolitan distribution and are found in freshwater and marine ecosystems.[2][1] Recent studies have proposed that the genus Rhopalodia should be recategorized to join Epithemia based on phylogenetic evidence,[3] although this change in nomenclature has been disputed.[4]

Members of this genus have endosymbionts that fix nitrogen called spheroid bodies, that are derived from cyanobacteria.[5][6] This endosymbiont is closely related to the nitroplast organelle.[2][7] Because of this close relationship, Epithemia has been proposed as a model system to study the early stages of organelle evolution.

Because of their nitrogen fixing endosymbionts, they can be a possible indicator of eutrophication, because Epithemia abundance decreased with increased ambient inorganic N concentrations.[8] High concentrations Epithemia species would mean that there is more fixed nitrogen in the ecosystem and could act as an early indicator of nutrient overload.

  1. ^ a b "Epithemia F.T.Kützing, 1844". www.gbif.org. Retrieved 23 April 2021.
  2. ^ a b Schvarcz, Christopher R.; Wilson, Samuel T.; Caffin, Mathieu; Stancheva, Rosalina; Li, Qian; Turk-Kubo, Kendra A.; White, Angelicque E.; Karl, David M.; Zehr, Jonathan P.; Steward, Grieg F. (2022-02-10). "Overlooked and widespread pennate diatom-diazotroph symbioses in the sea". Nature Communications. 13 (1): 799. Bibcode:2022NatCo..13..799S. doi:10.1038/s41467-022-28065-6. ISSN 2041-1723. PMC 8831587. PMID 35145076.
  3. ^ Ruck, Elizabeth C.; Nakov, Teofil; Alverson, Andrew J.; Theriot, Edward C. (2016-10-01). "Phylogeny, ecology, morphological evolution, and reclassification of the diatom orders Surirellales and Rhopalodiales". Molecular Phylogenetics and Evolution. 103: 155–171. Bibcode:2016MolPE.103..155R. doi:10.1016/j.ympev.2016.07.023. ISSN 1055-7903.
  4. ^ Kociolek, J.P.; Greenwood, M.; Hamsher, S.E.; Miller, S.; Li, J. (2024-04-02). "Valve ultrastructure of Rhopalodia constricta (W.Smith) Krammer (Rhopalodiales, Bacillariophyceae) and a consideration of its systematic placement". Diatom Research. 39 (2): 51–60. Bibcode:2024DiaRe..39...51K. doi:10.1080/0269249X.2024.2378769. ISSN 0269-249X.
  5. ^ Nakayama, Takuro; Kamikawa, Ryoma; Tanifuji, Goro; Kashiyama, Yuichiro; Ohkouchi, Naohiko; Archibald, John M.; Inagaki, Yuji (2014-08-05). "Complete genome of a nonphotosynthetic cyanobacterium in a diatom reveals recent adaptations to an intracellular lifestyle". Proceedings of the National Academy of Sciences. 111 (31): 11407–11412. Bibcode:2014PNAS..11111407N. doi:10.1073/pnas.1405222111. ISSN 0027-8424. PMC 4128115. PMID 25049384.
  6. ^ Nakayama, Takuro; Ikegami, Yuko; Nakayama, Takeshi; Ishida, Ken-ichiro; Inagaki, Yuji; Inouye, Isao (2011-01-01). "Spheroid bodies in rhopalodiacean diatoms were derived from a single endosymbiotic cyanobacterium". Journal of Plant Research. 124 (1): 93–97. Bibcode:2011JPlR..124...93N. doi:10.1007/s10265-010-0355-0. ISSN 1618-0860. PMID 20512519.
  7. ^ Abresch, Heidi; Bell, Tisza; Miller, Scott R (2024-01-01). "Diurnal transcriptional variation is reduced in a nitrogen-fixing diatom endosymbiont". The ISME Journal. 18 (1). doi:10.1093/ismejo/wrae064. ISSN 1751-7362. PMC 11131595. PMID 38637300.
  8. ^ Stancheva, Rosalina; Sheath, Robert G.; Read, Betsy A.; McArthur, Kimberly D.; Schroepfer, Chrystal; Kociolek, J. Patrick; Fetscher, A. Elizabeth (2013-12-01). "Nitrogen-fixing cyanobacteria (free-living and diatom endosymbionts): their use in southern California stream bioassessment". Hydrobiologia. 720 (1): 111–127. doi:10.1007/s10750-013-1630-6. ISSN 1573-5117. S2CID 254550477.