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Thalassiosira pseudonana

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Thalassiosira pseudonana
AThalassiosira pseudonanaoogonium(egg cell) beginning to expand through the cell wall. Artificial coloring denotes chlorophyll (blue) and DNA (red).
Scientific classificationEdit this classification
Domain: Eukaryota
Clade: Diaphoretickes
Clade: SAR
Clade: Stramenopiles
Phylum: Gyrista
Subphylum: Ochrophytina
Class: Bacillariophyceae
Order: Thalassiosirales
Family: Thalassiosiraceae
Genus: Thalassiosira
Species:
T. pseudonana
Binomial name
Thalassiosira pseudonana
Hasle & Heimdal, 1970

Thalassiosira pseudonanais a species of marine centricdiatoms.It was chosen as the firsteukaryoticmarinephytoplanktonfor wholegenome sequencing.[1]T. pseudonanawas selected for this study because it is a model for diatom physiology studies, belongs to a genus widely distributed throughout the world's oceans, and has a relatively small genome at 34 megabase pairs.Scientists are researching on diatom light absorption, using the marine diatom of Thalassiosira. The diatom requires a high enough concentration of CO2in order to utilize C4metabolism (Clementet al.2015).[2]

ThecloneofT. pseudonanathat was sequenced is CCMP 1335 and is available from theNational Center for Marine Algae and MicrobiotaatBigelow Laboratory for Ocean Sciences.This clone was originally collected in 1958 fromMoriches Bay(Long Island, New York) and has been maintained continuously inculture.

Morphology[edit]

Left: Scanning electron microscope image of theT. pseudonana.Right: False coloring of the biosilica structure ofT. pseudonanato highlight its valve region, fultoportulae and girdle band region.[3]

Thalassiosira pseudonanahas aradial symmetry.Its biosilica cell wall is divided into two halves, which are joined together by girdle bands, giving them a cylindrical shape or making them appear as a Petri dish.[4]The diameter of their valves ranges from 2 to 9 μm.[5][6]The valve is made up of silica ribs that radiate from the center with many 18 nm diameter nanopores between them.[7]The face of the valve has 0-1 centralfultoportulaand a marginal ring of fultoportulae (6-12).[8]The external openings of the central fultoportula appear as rimmed holes, whereas those of the marginal fultoportulae appear as short rimmed tubes, which are sometimes obliquely sectioned at the opening. On the internal face of the valve, two satellite pores surround the central fultoportula, while the marginal fultoportulae are surrounded by three satellite pores.[8]Therimoportulais a rimmed pore located on the valve face, with a size similar to the fultoportula, and positioned between two fultoportulae. Thepervalvaraxis ofT. pseudonanacan be either shorter than or equal to the valve diameter.[8]Their cell walls have been reported to mostly have low degree of silicification; however, their rims and ribs are highly silicified.[5][6][8]This probably enables them to have high strength while being light and using silica economically.[7][9]

Biomineralization[edit]

The distinct nano- to micro-scale structure ofT. pseudonanafollows a specific mechanism of formation. It begins with the formation of a thin base layer that outlines the valve.[7]Next, there is radiation of the silica ribs and the buildup of the rims, while portulae develop. The formation of the radial structure starts from a central location and spreads out in x and y axes planes.[7]During maturation, the valve surface becomes increasingly silicified, and the rim continues to develop, while the central portion of the valve becomes more rigid. Initially, the valve nanopores have irregular shapes, but they become circular during maturation.[7]The nanoscale structures ofT. pseudonanaare genetically mediated. The silicification process involves three categories of molecules: silaffins, which are highly post-translationally modified phosphoproteins; long chain polyamines (LCPAs); and silacidins, which are acidic proteins.[4]During valve synthesis, mRNA levels for silaffin 3 increase and lead to the formation of the base layer.[7]The presence of lower concentrations of silaffin 3 or the light form of silaffin 1 and 2 leads to the generation of spherical silica structures, indicating possible mechanisms involved in the formation of spherical silica in the ridges.[7]Over 150 genes have been identified as playing a role in the silicon biomineralization ofT. pseudonana.A set of 75 genes were upregulated only during silicon limitation, while 84 genes were upregulated by both silicon and iron limitations, indicating a linkage between their iron and silicon pathways.[4][10]T. pseudonanaalso possesses chitin-based scaffolds that are important in the formation of their biosilica structure.[11]

Symbiosis[edit]

Thalassiosira pseudonanaand the heterotrophicalphaproteobacteriumRuegeria pomeroyiform a chemicalsymbiosisin coculture. The bacteria providevitamin B12to the diatoms, which in exchange provide organic nutrients to the bacteria. In the presence of the diatom, the bacteria start producing a transporter for dihydroxypropanesulfonate (DHPS), a nutrient produced by the diatom for the bacteria.[12]A metabolic survey of the association between the bacteriumDinoroseobacter shibaeandT. pseudonanashowed that the bacterium has minimal impact on the growth ofT. pseudonana,but it causes metabolic changes by upregulating the intracellular amino acids and amino acid derivatives of the diatom.[13]It has been demonstrated that under conditions of environmental instability and extreme warming, biofilm formation can accelerate the evolutionary responses ofT. pseudonana.[14]

References[edit]

  1. ^Armbrust, E.;Berges, J.; Bowler, C.; Green, B.; Martinez, D.; Putnam, N.; Zhou, S.; Allen, A.; Apt, K.; Bechner, M.; Brzezinski, M. A.; Chaal, B. K.; Chiovitti, A.; Davis, A. K.; Demarest, M. S.; Detter, J. C.; Glavina, T.; Goodstein, D.; Hadi, M. Z.; Hellsten, U.; Hildebrand, M.; Jenkins, B. D.; Jurka, J.; Kapitonov, V. V.; Kröger, N.; Lau, W. W.; Lane, T. W.; Larimer, F. W.; Lippmeier, J. C.; Lucas, S. (2004). "The genome of the diatom Thalassiosira pseudonana: ecology, evolution, and metabolism".Science.306(5693): 79–86.Bibcode:2004Sci...306...79A.CiteSeerX10.1.1.690.4884.doi:10.1126/science.1101156.PMID15459382.S2CID8593895.
  2. ^Clement, R., Dimnet, L., Maberly, S. C., Gontero, B. 2015. The nature of the CO2‐concentrating mechanisms in a marine diatom,Thalassiosira pseudonana.New Phytologist Trust 209: 1417–1427.
  3. ^Gröger, Philip; Poulsen, Nicole; Klemm, Jennifer; Kröger, Nils; Schlierf, Michael (9 November 2016)."Establishing super-resolution imaging for proteins in diatom biosilica".Scientific Reports.6(1): 36824.Bibcode:2016NatSR...636824G.doi:10.1038/srep36824.ISSN2045-2322.PMC5101815.PMID27827427.
  4. ^abcArmbrust, E. Virginia (May 2009)."The life of diatoms in the world's oceans".Nature.459(7244): 185–192.Bibcode:2009Natur.459..185A.doi:10.1038/nature08057.ISSN1476-4687.PMID19444204.S2CID3738371.
  5. ^abHasle, G. R.; Heimdal, B. R. (1 April 1970)."Some Species of the Centric Diatom Genus Thalassiosira Studied in the Light and Electron Microscopes".Nova Hedwigia, Beihefte.31:543–581.doi:10.1127/nova.beihefte/31/1970/543.S2CID85688848.
  6. ^abRad Menendez, Cecilia (2011).Phenotypic and genotypic characterization of Thalassiosira pseudonana (Bacillariophyceae) strains(Ph.D. thesis). University of Aberdeen.
  7. ^abcdefgHildebrand, Mark; York, Evelyn; Kelz, Jessica I.; Davis, Aubrey K.; Frigeri, Luciano G.; Allison, David P.; Doktycz, Mitchel J. (October 2006)."Nanoscale control of silica morphology and three-dimensional structure during diatom cell wall formation".Journal of Materials Research.21(10): 2689–2698.Bibcode:2006JMatR..21.2689H.doi:10.1557/jmr.2006.0333.ISSN2044-5326.S2CID138652614.
  8. ^abcdHevia-Orube, Joana; Orive, Emma; David, Helena; Díez, Alejandro; Laza-Martínez, Aitor; Miguel, Irati; Seoane, Sergio (2 January 2016)."Molecular and morphological analyses of solitary forms of brackish Thalassiosiroid diatoms (Coscinodiscophyceae), with emphasis on their phenotypic plasticity".European Journal of Phycology.51(1): 11–30.doi:10.1080/09670262.2015.1077394.ISSN0967-0262.
  9. ^Hamm, Christian E.; Merkel, Rudolf; Springer, Olaf; Jurkojc, Piotr; Maier, Christian; Prechtel, Kathrin; Smetacek, Victor (February 2003)."Architecture and material properties of diatom shells provide effective mechanical protection".Nature.421(6925): 841–843.Bibcode:2003Natur.421..841H.doi:10.1038/nature01416.ISSN1476-4687.PMID12594512.S2CID4336989.
  10. ^Mock, T., Samanta, M. P., Iverson, V., Berthiaume, C., Robison, M., Holtermann, K.,... & Armbrust, E. V. (5 February 2008)."Whole-genome expression profiling of the marine diatom Thalassiosira pseudonana identifies genes involved in silicon bioprocesses".PNAS.105(5): 1579–1584.doi:10.1073/pnas.0707946105.PMC2234187.PMID18212125.{{cite journal}}:CS1 maint: multiple names: authors list (link)
  11. ^Brunner, Eike; Gröger, Christian; Lutz, Katharina; Richthammer, Patrick; Spinde, Katrin; Sumper, Manfred (1 September 2009)."Analytical studies of silica biomineralization: towards an understanding of silica processing by diatoms".Applied Microbiology and Biotechnology.84(4): 607–616.doi:10.1007/s00253-009-2140-3.ISSN1432-0614.PMID19629468.S2CID23179914.
  12. ^Kujawinski, Elizabeth B.;et al. (2016)."The Ocean Microbiome: Metabolic Engine of the Marine Carbon Cycle".Microbe Magazine.11(6): 262–267.doi:10.1128/microbe.11.262.1.
  13. ^Paul, Carsten; Mausz, Michaela A.; Pohnert, Georg (1 April 2013)."A co-culturing/metabolomics approach to investigate chemically mediated interactions of planktonic organisms reveals influence of bacteria on diatom metabolism".Metabolomics.9(2): 349–359.doi:10.1007/s11306-012-0453-1.ISSN1573-3890.S2CID255127394.
  14. ^Schaum, C.‐E. (March 2019)."Enhanced biofilm formation aids adaptation to extreme warming and environmental instability in the diatom Thalassiosira pseudonana and its associated bacteria".Limnology and Oceanography.64(2): 441–460.Bibcode:2019LimOc..64..441S.doi:10.1002/lno.11050.ISSN0024-3590.S2CID92224508.

Further reading[edit]

Meksiarun, Phiranuphon; Spegazzini, Nicolas; Matsui, Hiroaki; Nakajima, Kensuke; Matsuda, Yusuke; Sato, Hidetoshi (January 2015). "In Vivo Study of Lipid Accumulation in the Microalgae Marine Diatom Thalassiosira pseudonana Using Raman Spectroscopy".Applied Spectroscopy.69(1): 45–51.Bibcode:2015ApSpe..69...45M.doi:10.1366/14-07598.PMID25506782.S2CID40963425.

Yi, Andy Xianliang; Leung, Priscilla T. Y.; Leung, Kenneth M. Y. (September 2014). "Photosynthetic and molecular responses of the marine diatom Thalassiosira pseudonana to triphenyltin exposure".Aquatic Toxicology.154:48–57.doi:10.1016/j.aquatox.2014.05.004.PMID24858899.

Luo, Chun-Shan; Liang, Jun-Rong; Lin, Qun; Li, Caixia; Bowler, Chris; Anderson, Donald; Wang, Peng; Wang, Xin-Wei; Gao, Ya-Hui (December 2014)."Cellular Responses Associated with ROS Production and Cell Fate Decision in Early Stress Response to Iron Limitation in the Diatom Thalassiosira pseudonana".Journal of Proteome Research.13(12): 5510–5523.doi:10.1021/pr5004664.PMC4261981.PMID25372880.

Sunda, William G.; Shertzer, Kyle W.; Coggins, Lew (October 2014)."Positive feedbacks between bottom-up and top-down controls promote the formation and toxicity of ecosystem disruptive algal blooms: A modeling study".Harmful Algae.39:342–356.doi:10.1016/j.hal.2014.09.005.

Samukawa, Mio; Shen, Chen; Hopkinson, Brian; Matsuda, Yusuke (2014). "Localization of putative carbonic anhydrases in the marine diatom, Thalassiosira pseudonana".Photosynthesis Research.121(2–3): 235–249.doi:10.1007/s11120-014-9967-x.PMID24414291.S2CID12444516.

Delalat, Bahman; Sheppard, Vonda C.; Ghaemi, Soraya Rasi; Rao, Shasha; Prestidge, Clive A.; McPhee, Gordon; Rogers, Mary-Louise; Donoghue, Jaqueline F.; Pillay, Vinochani; Johns, Terrance G.; Kroeger, Nils; Voelcker, Nicolas H. (2015)."Targeted drug delivery using genetically engineered diatom biosilica".Nature Communications.6:8791.Bibcode:2015NatCo...6.8791D.doi:10.1038/ncomms9791.hdl:11343/240712.PMID26556723.

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