{{Short description|Liquid crystal transition state}} '''Tactoids''' are liquid crystal microdomains nucleated in isotropic phases, which can be distinguished as spherical or spindle-shaped birefringent microdroplets under polarized light microscopy. Tactoids are a transition state between isotropic and macroscopic liquid crystalline phases. The first observation of tactoids was made by Zocher in 1925, when he studied the nematic phase formed in vanadium pentoxide sols.<ref>{{cite journal|title=Über freiwillige Strukturbildung in Solen. (Eine neue Art anisotrop flüssiger Medien)|journal= Zeitschrift für anorganische und allgemeine Chemie|volume= 147|pages= 91–110|doi= 10.1002/zaac.19251470111|year= 1925|last1= Zocher|first1= H.|bibcode= 1925ZAACh.147...91Z}}</ref> After that, tactoids have been found in the phase transition processes in many lyotropic liquid crystalline substances, such as tobacco mosaic virus,<ref>{{cite journal|title= Liquid crystalline substances from virus-infected plants|journal=Nature|volume=138|issue=3503|pages=1051|doi=10.1038/1381051a0|year=1936|last1=Bawden|first1=F. C.|last2=Pirie|first2=N. W.|last3=Bernal|first3=J. D.|last4=Fankuchen|first4=I.|authorlink4=Isidor Fankuchen|authorlink3=J. D. Bernal| bibcode=1936Natur.138.1051B}}</ref> polypeptides,<ref>{{cite journal|title= Liquid-crystalline structures in solutions of a polypeptide|journal= Transactions of the Faraday Society|volume= 52|pages= 571|doi= 10.1039/TF9565200571|year= 1956|last1= Robinson|first1= Conmar}}</ref> and cellulose nanocrystals.<ref>{{cite journal|title= Helicoidal self-ordering of cellulose microfibrils in aqueous suspension|journal=International Journal of Biological Macromolecules|volume=14|issue=3|pages=170–172|doi=10.1016/S0141-8130(05)80008-X|pmid=1390450|year=1992|last1=Revol|first1=J.-F.|last2=Bradford|first2=H.|last3=Giasson|first3=J.|last4=Marchessault|first4=R.H.|last5=Gray|first5=D.G.}}</ref>
== In biology == It has been shown that filamin causes actin to condense into tactoids.<ref>{{Cite journal |last1=Weirich |first1=Kimberly L. |last2=Banerjee |first2=Shiladitya |last3=Dasbiswas |first3=Kinjal |last4=Witten |first4=Thomas A. |last5=Vaikuntanathan |first5=Suriyanarayanan |last6=Gardel |first6=Margaret L. |date=2017-02-28 |title=Liquid behavior of cross-linked actin bundles |journal=Proceedings of the National Academy of Sciences |language=en |volume=114 |issue=9 |pages=2131–2136 |doi=10.1073/pnas.1616133114 |doi-access=free |issn=0027-8424 |pmc=5338483 |pmid=28202730|bibcode=2017PNAS..114.2131W }}</ref> The filamentous phage Pf4 generates a tactoid shell around host ''P. aeruginosa'' cells that confer antibiotic resistance.<ref>{{cite journal | last1=Secor | first1=Patrick R. | last2=Sweere | first2=Johanna M. | last3=Michaels | first3=Lia A. | last4=Malkovskiy | first4=Andrey V. | last5=Lazzareschi | first5=Daniel | last6=Katznelson | first6=Ethan | last7=Rajadas | first7=Jayakumar | last8=Birnbaum | first8=Michael E. | last9=Arrigoni | first9=Allison | last10=Braun | first10=Kathleen R. | last11=Evanko | first11=Stephen P. | last12=Stevens | first12=David A. | last13=Kaminsky | first13=Werner | last14=Singh | first14=Pradeep K. | last15=Parks | first15=William C. | last16=Bollyky | first16=Paul L. | title=Filamentous Bacteriophage Promote Biofilm Assembly and Function | journal=Cell Host & Microbe | volume=18 | issue=5 | date=2015 | pmid=26567508 | pmc=4653043 | doi=10.1016/j.chom.2015.10.013 | pages=549–559}}</ref>
==References== {{reflist}}
Category:Biochemistry Category:Chemical properties Category:Liquid crystals
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