Braarudosphaera bigelowii
{{short description|Dodecahedron shaped coccolithophore}}
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{{Use dmy dates|date=April 2024}}
{{Taxobox
| name = Braarudosphaera bigelowii
| fossil_range = {{fossil_range|Late Cretaceous|present}}
| image = Braarudosphaera bigelowii.jpg
| image_upright =
| image_alt =
| image_caption =
| domain = Eukaryota
| unranked_phylum = Haptophyta
| classis = Prymnesiophyceae
| ordo = Coccosphaerales
| familia = Braarudosphaeraceae
| genus = Braarudosphaera
| species = B. bigelowii
| binomial = Braarudosphaera bigelowii
| binomial_authority = (Gran & Braarud) Deflandre{{AlgaeBase species|name=Braarudosphaera bigelowii|id=56425}}
}}
Braarudosphaera bigelowii is a coastal coccolithophore in the fossil record going back 100 million years to the Late Cretaceous.
Coccolithophore
The family Braarudosphaeraceae consist of single-celled coastal phytoplanktonic algae with calcareous scales with five-fold symmetry, called pentaliths. With 12 sides, it has a regular dodecahedral structure, approximately 10 micrometers across.{{cite journal |last1=Hagino |first1=Kyoko |last2=Onuma |first2=Ryo |last3=Kawachi |first3=Masanobu |last4=Horiguchi |first4=Takeo |title=Discovery of an Endosymbiotic Nitrogen-Fixing Cyanobacterium UCYN-A in Braarudosphaera bigelowii (Prymnesiophyceae) |journal=PLOS ONE |date=4 December 2013 |volume=8 |issue=12 |pages=e81749 |doi=10.1371/journal.pone.0081749 |doi-access=free |pmid=24324722 |pmc=3852252 |bibcode=2013PLoSO...881749H }}{{cite web |last=Baisas |first=Laura |date=2024-04-18 |title=For the first time in one billion years, two lifeforms truly merged into one organism |url=https://www.popsci.com/science/two-lifeforms-merged-into-one/ |access-date=2024-04-19 |website=Popular Science}}
File:Braarudosphaera bigelowii.png image of a cell of B. bigelowii surrounded by 12 pentaliths. A pentalith (calcareous scale of the Braarudosphaeraceae) indicated by the blue open pentagon consists of five trapezoidal segments. Black arrow indicates "side length of the pentalith" where the measurements were conducted. (B) SEM image of pentalith of B. bigelowii (proximal side). (C) Close up of proximal side in previous image showing laminar structure. (D) – (F) light microscope images of three different specimens.]]
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Nitroplast
File:Braarudosphaera Bigelowii Nitroplast.webp inside B. bigelowii (coccoliths removed), marked by a black arrow. Like other haptophytes, the cell has 2 unequal flagella. ]]
B. bigelowii has a nitroplast organelle, originated some 100 million years ago from a cyanobacterial endosymbiont called UCYN-A2, which allows B. bigelowii to fix nitrogen and convert it into compounds useful for cell growth.{{cite journal |last1=Massana |first1=Ramon |title=The nitroplast: A nitrogen-fixing organelle |journal=Science |date=12 April 2024 |volume=384 |issue=6692 |pages=160–161 |doi=10.1126/science.ado8571 |pmid=38603513 |hdl=10261/354070 |hdl-access=free }}{{cite journal |last1=Wong |first1=Carissa |title=Scientists discover first algae that can fix nitrogen — thanks to a tiny cell structure |journal=Nature |date=25 April 2024 |volume=628 |issue=8009 |pages=702 |doi=10.1038/d41586-024-01046-z |pmid=38605201 }}{{Cite press release |url=https://newscenter.lbl.gov/2024/04/17/scientists-discover-first-nitrogen-fixing-organelle/ |title=Scientists Discover First Nitrogen-Fixing Organelle |date=17 April 2024 |publisher=Lawrence Berkeley National Laboratory }} This phenomenon is previously known from diatoms in the family Rhopalodiaceae, where a nitrogen fixing and non-photosynthetic cyanobacterial endosymbiont, a diazoplast, provides the photosynthetic host cell with nitrogen.{{cite journal |last1=Moulin |first1=Solène L. Y. |last2=Frail |first2=Sarah |last3=Braukmann |first3=Thomas |last4=Doenier |first4=Jon |last5=Steele-Ogus |first5=Melissa |last6=Marks |first6=Jane C. |last7=Mills |first7=Matthew M. |last8=Yeh |first8=Ellen |title=The endosymbiont of Epithemia clementina is specialized for nitrogen fixation within a photosynthetic eukaryote |journal=ISME Communications |date=15 April 2024 |volume=4 |pages=ycae055 |doi=10.1093/ismeco/ycae055 |doi-access=free |pmid=38707843 |pmc=11070190 }}{{cite journal |last1=Nakayama |first1=Takuro |last2=Inagaki |first2=Yuji |title=Genomic divergence within non-photosynthetic cyanobacterial endosymbionts in rhopalodiacean diatoms |journal=Scientific Reports |date=12 October 2017 |volume=7 |issue=1 |page=13075 |doi=10.1038/s41598-017-13578-8 |pmid=29026213 |pmc=5638926 |bibcode=2017NatSR...713075N }}
Name
The genus name Braarudosphaera is in honour of Norwegian botanist Trygve Braarud (1903–1985). He specialized in marine biology, and was affiliated with the University of Oslo.{{cite book |doi=10.3372/epolist2022 |title=Eine Enzyklopädie zu eponymischen Pflanzennamen: Von Menschen & ihren Pflanzen |trans-title=An encyclopedia on eponymous plant names: About people & their plants |language=de |date=2022 |last1=Burkhardt |first1=Lotte |isbn=978-3-946292-41-8|page=B-110}}
References
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External links
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