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{{Short description|Genus of single-celled organisms}}
{{Automatic taxobox
| image = Mikrofoto.de-Blepharisma japonicum 15.jpg
| image_caption = ''[[Blepharisma japonicum]]''
| taxon = Blepharisma
| authority = Perty, 1852
}}

'''''Blepharisma''''' is a [[genus]] of [[unicellular]] [[ciliate]] [[protists]] found in fresh and salt water. The group includes about 40 accepted species, and many sub-varieties and strains. While species vary considerably in size and shape, most are easily identified by their red or pinkish color, which is caused by granules of the pigment blepharismin.<ref>{{cite journal | title = Defensive Function of Pigment Granules in ''Blepharisma japonicum'' | journal = European Journal of Protistology | date = June 29, 1990 | last1 = Miyake| volume = 25 | pages = 310–315| doi = 10.1016/S0932-4739(11)80122-7 | pmid = 23196043 | first1 = Akio | issue = 4|display-authors=etal}}</ref>

All members of the genus possess a long series of [[membranelle]]s on the left side of the oral groove, and an "undulating membrane" (a structure resembling a flap, scarf or small sail, composed of long cilia fused together as a single sheet) on the right side of the [[peristome]], toward the posterior.<ref name="Hirshfield">{{cite journal | title = A proposed organization of the genus ''Blepharisma'' Perty and description of four new species | journal = The Journal of Protozoology | last = Hirshfield | volume = 12 | issue = 1 | pages = 136–144| doi=10.1111/j.1550-7408.1965.tb01826.x|display-authors=etal| year = 1965 }}</ref>

Certain species of ''Blepharisma'' have served as [[model organism]]s for scientific research. Since some varieties are easily cultured and readily available from scientific supply houses, they are a common object of study in school science classes.

==Appearance==
''Blepharisma'' may be as small as 50 micrometres in length, or as large as 1 mm (though normal size range is between 75 and 300 micrometres).<ref name="Hirshfield" /> Body shape varies within the genus. The [[type species]] of the genus, ''B. persicinum,'' is ellipsoidal. ''Blepharisma lateritium'' is teardrop-shaped, with a rounded posterior; while ''Blepharisma elongatum'' and ''Blepharisma sphagni'' are long and thin, tapering at the posterior into a tail-like point.<ref>{{cite book | last1 = Kahl | first1 = Alfred | title = Urtiere oder Protozoa I: Wimpertiere oder Ciliata (Infusoria) In: Die Tierwelt Deutschlands | volume = 3 Spirotricha |editor= F. Dahl | publisher = G. Fischer | date = 1930–1935 | location = Jena | pages = 442–448 }}</ref>

All species are uniformly ciliated, with the cilia arranged in longitudinal rows, and stripes of pigment alternating between rows of cilia. Cilia, short hairlike organelles, sweep food into its mouth and are used for movement.<ref>{{cite web|last1=Hanna|first1=Jannette|title=Blepharism|url=http://www.microscopy-uk.org.uk/mag/artnov04macro/jhblepharisma.html|website=Micscape Magazine|access-date=29 June 2017}}</ref> The pink or red pigmentation may be quite pale, and in certain cases it is absent altogether.<ref>{{cite journal | title = Reversible bleaching of ''Blepharisma'' | journal = Transactions of the American Microscopical Society | date = Jan 1938 | first = Arthur | last = Giese | volume = 57 | issue = 1 | pages = 77–81| doi = 10.2307/3222804| jstor = 3222804 }}</ref> A [[contractile vacuole]], often quite large, is located in the posterior. The [[Macronucleus|Macronuclei]] can take a variety of forms. Depending on species and phase of life, they may be rod-shaped, ovoid, spherical, or moniliform (like a rosary, or string of beads).

==Reproduction and sexual phenomena==
[[File:Blepharisma diagram.png|thumb|upright=1.5|left| {{center|''Blepharisma'' morphology}}]]

Like all ciliates, ''Blepharisma'' reproduce asexually, by [[fission (biology)|binary fission]], dividing transversally. Fission may occur spontaneously, as part of the [[vegetative reproduction|vegetative]] [[cell cycle]], or it may follow a sexual phenomenon called [[isogamy|conjugation]], a process through which genetic material is exchanged between cells. In conjugation, two organisms come into close contact, and a temporary cytoplasmic bridge forms between them. The [[micronuclei]] of each cell then undergo [[meiosis]], and [[haploid]] micronuclei pass from one individual to the other. This permits the reshuffling of hereditary characteristics, as in other types of [[sexual reproduction]]. Conjugation is immediately followed by binary fission of the two conjugants.<ref>{{cite book | last1 = Lynn | first1 = Denis H. | title = The Ciliated Protozoa: Characterization, Classification and Guide to the Literature | edition = 3 | publisher = Springer | year = 2007 | pages = 23}}</ref>

In ''Blepharisma'', as in some other ciliates, chemical substances called gamones are used to induce conjugation by stimulating interaction between compatible mating partners.<ref>{{cite journal | title = Developmentally and environmentally regulated expression of gamone 1: the trigger molecule for sexual reproduction in ''Blepharisma japonicum'' | journal = Journal of Cell Science | date = 31 May 2005 | last1 = Sugiura| doi = 10.1242/jcs.02359 | first1 = M. | volume = 118 | issue = 12 | pages = 2735–41|display-authors=etal | pmid=15928050| doi-access = free }}</ref>

Although clonal cells of ''Blepharisma'' are sometimes able to conjugate with one another (a phenomenon known as [[selfing]]),<ref name=Miyake>Miyake A. (1981). Cell interaction by gamones in Blepharisma In: Sexual Interactions in Eukaryotic Microbes (O’Day, D.H. editor), pp. 95-129 New York: Academic Press. {{ISBN|978-0124312975}}</ref> conjugation ordinarily involves the interaction of cells of different mating types. In the species ''Blepharisma japonicum'', there are two mating types (I and II), each type excreting a specific pheromone (termed gamone 1 and gamone 2, respectively).<ref name=Miyake /><ref name="pmid20167456">{{cite journal |vauthors=Sugiura M, Shiotani H, Suzaki T, Harumoto T |title=Behavioural changes induced by the conjugation-inducing pheromones, gamone 1 and 2, in the ciliate Blepharisma japonicum |journal=Eur. J. Protistol. |volume=46 |issue=2 |pages=143–9 |year=2010 |pmid=20167456 |doi=10.1016/j.ejop.2010.01.002 }}</ref> When sexually mature mating-type I cells are moderately starved, they autonomously produce and secrete gamone I.<ref name=Miyake /> Gamone 1 specifically acts on mating-type II cells, transforming them so that they can unite with type I cells, and inducing them to secrete gamone 2. Gamone 2 then transforms type I cells so that they can unite with type II cells. Cells that can unite may then undergo conjugation. Conjugation of opposite mating types promotes [[outcrossing]] and the masking of deleterious recessive mutations in the diploid phase of the sexual cycle.<ref name="pmid9299310">{{cite journal |vauthors=Bernstein C, Bernstein H |title=Sexual communication |journal=J. Theor. Biol. |volume=188 |issue=1 |pages=69–78 |year=1997 |pmid=9299310 |doi=10.1006/jtbi.1997.0459 |bibcode=1997JThBi.188...69B }}</ref>

{{clear}}

==Feeding and behavior==
''Blepharisma'' feed on a variety of smaller organisms, including [[bacteria]], [[flagellate|flagellate algae]], [[rotifer]]s, other ciliates and even smaller members of the same species. Experiments with ''Blepharisma undulans'' have shown that cannibalism causes gigantism. When individuals are given a diet of smaller ''Blepharisma'', or certain ciliates (particularly ''[[Colpidium colpoda]]'' or ''[[Tetrahymena]]''), they grow to a relatively enormous size. As long as their diet remains unchanged, cannibal giants will divide to produce more giants. When large prey become unavailable, the offspring will revert to normal size.<ref>{{cite journal | title = Cannibalism and Gigantism in Blepharisma | journal = Transactions of the American Microscopical Society | year = 1938 | first = Arthur | last = Giese | volume = 57 | issue = 3 | pages = 245–255| doi = 10.2307/3222693| jstor = 3222693 }}</ref>

=== Photobiology ===
{{Chembox
| Name = Blepharismin C

| ImageFile = Blepharismin C.svg
| ImageAlt =

| IUPACName = 5,7,11,13,17,19,23,25-octahydroxy-15-(4-hydroxyphenyl)-6,24-di(propan-2-yl)octacyclo[14.11.1.12,10.03,8.04,26.020,28.022,27.014,29]nonacosa-1,3,5,7,10(29),11,13,16,18,20(28),22,24,26-tridecaene-9,21-dione

| OtherNames =

| Section1 = {{Chembox Identifiers
| CASNo = 129898-49-3
| ChemSpiderID = 9942356
| PubChem = 11767671
| SMILES = CC(C)C1=C(C2=C3C4=C5C6=C(C(=CC(=C6C(C7=C(C=C(C(=C74)C(=O)C3=C1O)O)O)C8=CC=C(C=C8)O)O)O)C(=O)C9=C(C(=C(C2=C59)O)C(C)C)O)O
| StdInChI=1S/C41H30O11/c1-11(2)19-36(47)32-30-28-26-22(15(43)9-17(45)24(26)40(51)34(30)38(19)49)21(13-5-7-14(42)8-6-13)23-16(44)10-18(46)25-27(23)29(28)31-33(32)37(48)20(12(3)4)39(50)35(31)41(25)52/h5-12,21,42-50H,1-4H3
| StdInChIKey = FRDONCXLMWOCKJ-UHFFFAOYSA-N
}}
| Section2 = {{Chembox Properties
|C=41|H=30|O=11
| MolarMass =
| Appearance =
| Density =
| MeltingPt =
| BoilingPt =
| Solubility =
}}
| Section3 = {{Chembox Hazards
| MainHazards =
| FlashPt =
| AutoignitionPt =
}}
}}
''Blepharisma'' are markedly [[photophobia (biology)|photophobic]], and when light levels are increased will seek out darkened areas. The ability to detect light is accomplished with photosensitive pigment granules located just under the [[plasma membrane]] of the cell. The pigment in these granules is [[blepharismin]], the same substance that gives ''Blepharisma'' their characteristic pinkish color.<ref>{{cite journal | title = Analyses of Structure of Photoreceptor Organelle and Blepharismin associated Protein in Unicellular Eukaryote ''Blepharisma'' | journal = Photochemistry and Photobiology | year = 2000 | last = Matsuoka | volume = 57 | issue = 3 | pages = 245–255|display-authors=etal | pmid = 11107859 | doi = 10.1562/0031-8655(2000)0720709AOSOPO2.0.CO2 | s2cid = 204166047 }}</ref> ''Blepharisma'' are usually pink when collected in nature, but when grown in darkness with abundant food they turn red. Exposure to light or starvation causes them to lose their color, but deeply-pigmented cells can even be killed by strong light.<ref>{{Cite book|title=Photochemical and Photobiological Reviews|last=Giese|first=Arthur C.|date=1981|publisher=Springer, Boston, MA|pages=139–180|language=en|doi=10.1007/978-1-4684-7003-1_4|chapter = The Photobiology of ''Blepharisma''|isbn = 978-1-4684-7005-5}}</ref>

==List of species==
[[File:Blepharisma hyalinum - 160x - Länge 200µ (10388446276).jpg|thumb|upright=1.1| {{center|''Blepharisma hyalinum''}}]]
[[File:Blepharisma americana.ogv|thumb|upright=1.1|''Blepharisma americanum'' swimming in a drop of pond water, with other microorganisms.]]
[[File:Mikrofoto.de-Blepharisma japonicum 21.jpg|thumb|upright=1.1|right| {{center|''Blepharisma japonicum''}}]]

* ''[[Blepharisma americanum|B. americanum]]'' Suzuki, 1954
* ''[[Blepharisma bimicronucleatum|B. bimicronucleatum]]'' Villeneuve-Brachon 1940
* ''[[Blepharisma bothrostoma|B. bothrostoma]]'' Mermod 1914
* ''[[Blepharisma botezati|B. botezati]]'' Lepsi, 1926
* ''[[Blepharisma coeruleum|B. coeruleum]]'' Gajevskaja, 1927
* ''[[Blepharisma caudatus|B. caudatus]]'' Dumas 1937
* ''[[Blepharisma clarissimum|B. clarissimum]]'' Kahl, 1928
* ''[[Blepharisma dawsoni|B. dawsoni]]'' Christie & Hirshfield 1967
* ''[[Blepharisma dileptus|B. dileptus]]'' Kahl, 1928
* ''[[Blepharisma elegans|B. elegans]]'' Vuxanovici 1963
* ''[[Blepharisma elongatum|B. elongatum]]'' (Stokes, 1884) Kahl, 1926
* ''[[Blepharisma falcatum|B. falcatum]]'' Gelei 1954
* ''[[Blepharisma galianoi|B. galianoi]]'' Fernandez-Leborans 1979
* ''[[Blepharisma grayi|B. grayi]]'' Hartwig & Parker, 1977
* ''[[Blepharisma halophila|B. halophila]]'' Ruinen 1938
** Found to be a phylogenetic outlier under the [[orthographical variant]] ''Blepharisma halophilum''.<ref>{{cite journal |last1=Chi |first1=Yong |last2=Chen |first2=Xiangrui |last3=Li |first3=Yuqing |last4=Wang |first4=Chundi |last5=Zhang |first5=Tengteng |last6=Ayoub |first6=Alex |last7=Warren |first7=Alan |last8=Song |first8=Weibo |last9=Wang |first9=Yuanyuan |title=New contributions to the phylogeny of the ciliate class Heterotrichea (Protista, Ciliophora): analyses at family-genus level and new evolutionary hypotheses |journal=Science China Life Sciences |date=1 April 2021 |volume=64 |issue=4 |pages=606–620 |doi=10.1007/s11427-020-1817-5|pmid=33068287 |s2cid=223558791 }}</ref>
* ''[[Blepharisma hyalinum|B. hyalinum]]'' Perty, 1852
* ''[[Blepharisma intermedium|B. intermedium]]'' Bhandary, 1962
* ''[[Blepharisma ichthyoides|B. ichthyoides]]'' V. Gelei, 1933
* ''[[Blepharisma japonicum|B. japonicum]]'' (Suzuki, 1954) Giese, 1973
* ''[[Blepharisma lateritium|B. lateritium]]'' (Ehrenberg, 1831) Kahl, 1932
* ''[[Blepharisma lentis|B. lentis Gelei]]'' 1954
* ''[[Blepharisma melana|B. melana]]'' Borror, 1963
* ''[[Blepharisma minima|B. minima]]'' Lepsi, 1926
* ''[[Blepharisma multinucleata|B. multinucleata]]'' Dragesco, 1960
* ''[[Blepharisma musculus|B. musculus]]'' Penard, 1922
* ''[[Blepharisma ovalis|B. ovalis]]'' Dumas 1937
* ''[[Blepharisma ovatum|B. ovatum]]'' Penard, 1922
* ''[[Blepharisma parasalinarum|B. parasalinarum]]'' Dragesco 1997
* ''[[Blepharisma persicinum|B. persicinum]]'' Perty, 1849
* ''[[Blepharisma salinarum|B. salinarum]]'' Florentin, 1899
* ''[[Blepharisma seshachari|B. seshachari]]'' Bhandary, 1962
* ''[[Blepharisma sphagni|B. sphagni]]'' Lepsi, 1926
* ''[[Blepharisma steini|B. steini]]'' Kahl, 1932
* ''[[Blepharisma tardum|B. tardum]]'' Kahl, 1928
* ''[[Blepharisma undulans|B. undulans]]'' Stein, 1868
* ''[[Blepharisma velatum|B. velatum]]'' Vacelet, 1961
* ''[[Blepharisma vestitum|B. vestitum]]'' Kahl, 1928
* ''[[Blepharisma violaceae|B. violaceae]]'' Tucolesco 1962
* ''[[Blepharisma vitreum|B. vitreum]]'' Lepsi 1957
* ''[[Blepharisma wardsi|B. wardsi]]'' Hirshfield, Isquith & Bhandary, 1965

== References ==
{{Reflist}}

== Further reading ==

* Giese, Arthur C. (1973) ''Blepharisma: the biology of a light-sensitive protozoan''. Stanford, California, Stanford University Press. 366 pp. https://archive.org/details/blepharismabiolo0000gies
* {{cite journal |last1=Lobban |first1=Christopher S. |last2=Hallam |first2=Steven J. |last3=Mukherjee |first3=Prasun |last4=Petrich |first4=Jacob W. |title=Photophysics and Multifunctionality of Hypericin-Like Pigments in Heterotrich Ciliates: A Phylogenetic Perspective |journal=Photochemistry and Photobiology |date=September 2007 |volume=83 |issue=5 |pages=1074–1094 |doi=10.1111/j.1751-1097.2007.00191.x |pmid=17880503 |doi-access=free}}

{{Taxonbar|from=Q4926105}}
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[[Category:Heterotrichea]]
[[Category:Ciliate genera]]

Blepharisma - Revision history

imported>Plantdrew: typo