Triparma

{{Short description|Genus of single-celled organisms}}

{{Use dmy dates|date=April 2018}}

{{Taxobox

| name = Triparma

| image = Triparma eleuthera.jpg

| image_caption = The flagellated Triparma eleuthera

| image_upright = 1.1

| domain = Eukaryota

| unranked_regnum = SAR

| superphylum = Heterokonta

| phylum = Ochrophyta

| classis = Bolidophyceae

| ordo = Parmales

| familia = Triparmaceae

| genus = Triparma

| genus_authority = Booth and Marchant 1987

| subdivision_ranks = Species

| subdivision =

• Triparma columacea
• Triparma eleuthera
• Triparma laevis
• Triparma mediterranea
• Triparma pacifica
• Triparma retinervis
• Triparma strigata
• Triparma verrucosa

| synonyms =

• Bolidomonas

}}

Triparma is a genus of unicellular algae in the family Triparmaceae in the order Parmales. They form siliceous plates on the cell surface that aid in identification. Triparma is distinguished by its possession of three shield plates, three triradiate girdle plates, a triradiate girdle plate with notched ends, and a small ventral plate.{{cite journal|last1=Konno|first1=Susumu|last2=Jordan|first2=Richard W.|title=An amended terminology for the Parmales (Chrysophyceae)|journal=Phycologia|date=November 2007|volume=46|issue=6|pages=612–616|doi=10.2216/07-29.1|s2cid=85351649}} It was first described by Booth & Marchant in 1987 and the holotype is Triparma columacea.

{{multiple image

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| direction = horizontal

| width = 130

| header = Triparma laevis silicate shell{{hsp}}Booth, B.C. and Marchant, H.J. (1987) "Parmales, a new order of marine chrysophytes, with descriptions of three new genera and seven new species". Journal of Phycology, 23: 245–260. {{doi|10.1111/j.1529-8817.1987.tb04132.x}}.Kuwata, A., Yamada, K., Ichinomiya, M., Yoshikawa, S., Tragin, M., Vaulot, D. and Lopes dos Santos, A. (2018) "Bolidophyceae, a sister picoplanktonic group of diatoms – a review". Frontiers in Marine Science, 5: 370. {{doi|10.3389/fmars.2018.00370|doi-access=free}}. 50px Material was copied from this source, which is available under a [https://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International License].

| header_align = center

| image1 = Triparma laevis and shell.jpg

| caption1 = The silicated Triparma laevis (top) and a drawing of its shell, scale bar = 1 μm.

| image2 = Triparma laevis exploded shell.jpg

| caption2 = Exploded shell: D = dorsal plate, G = girdle plate, S = shield plate and V = ventral plate.

| footer =

}}

Triparma cells have two forms: the motile, naked form and the non-motile siliceous form. The motile cells propelled by two flagella of unequal length, typical of heterokonts. The non-motile forms do not possess flagella but instead have a silicified cell wall with a distinctive plate morphology: three shield plates, three oblong girdle plates, a triradiate dorsal plate with rounded ends, and a large ventral plate. Both forms contain a single, dorsal chloroplast that contains chlorophylls a and c_1-3 as well as fucoxanthin. They are typically 1-2 μm in size and generally spherical or heart-shaped.{{cite journal|last1=Ichinomiya|first1=Mutsuo|last2=dos Santos|first2=Adriana Lopes|last3=Gourvil|first3=Priscillia|last4=Yoshikawa|first4=Shinya|last5=Kamiya|first5=Mitsunobu|last6=Ohki|first6=Kaori|last7=Audic|first7=Stéphane|last8=de Vargas|first8=Colomban|last9=Noël|first9=Mary-Hélène|last10=Vaulot|first10=Daniel|last11=Kuwata|first11=Akira|title=Diversity and oceanic distribution of the Parmales (Bolidophyceae), a picoplanktonic group closely related to diatoms|journal=The ISME Journal|date=22 March 2016|volume=10|issue=10|pages=2419–2434|doi=10.1038/ismej.2016.38|pmid=27003244|accessdate=10 April 2018|url=http://hal.upmc.fr/hal-01292953/document|pmc=5030691}}

The genus Triparma is actively studied because of their close relationship to the diatoms, and it has been discovered that they have different silica-limitation responses. While diatoms stop growing and cell division is inhibited under low-silica conditions, Triparma continues to grow and divide normally even under nanomolar concentrations of silica, although the silica plates are no longer produced.{{cite journal|last1=Yamada|first1=Kazumasa|last2=Yoshikawa|first2=Shinya|last3=Ichinomiya|first3=Mutsuo|last4=Kuwata|first4=Akira|last5=Kamiya|first5=Mitsunobu|last6=Ohki|first6=Kaori|last7=Lovejoy|first7=Connie|title=Effects of Silicon-Limitation on Growth and Morphology of Triparma laevis NIES-2565 (Parmales, Heterokontophyta)|journal=PLOS ONE|date=23 July 2014|volume=9|issue=7|pages=e103289|doi=10.1371/journal.pone.0103289|pmid=25054645|pmc=4108440|doi-access=free}}

Photosynthetic pigments present in bolydophyte chloroplasts include chlorophylls a, c₁, c₂, c₃, fucoxanthin, diatoxanthin, diadinoxanthin.{{cite journal |vauthors=Dimier C, Giovanni S, Ferdinando T, Brunet C |title=Comparative Ecophysiology of the Xanthophyll Cycle in Six Marine Phytoplanktonic Species |journal=Protist |volume= 160|issue= 3|pages= 397–411|date=April 2009 |pmid=19375387 |doi=10.1016/j.protis.2009.03.001 }}

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