Editing Cryptomonas

{{Short description|Genus of single-celled organisms}}
{{Automatic taxobox 
| taxon = Cryptomonas
| authority = [[Christian Gottfried Ehrenberg|Ehrenberg]], 1831
| type_species = ''Cryptomonas ovata''
| type_species_authority = Ehrenberg 1831
| subdivision_ranks = Species
| subdivision = See text
| synonyms = 
* ''[[Campylomonas]]'' <small>Hill 1991</small>
* ''[[Cryptochrysis]]'' <small>Pascher 1911</small>
* ''[[Chroomonas]]'' (''Cryptochrysis'') <small>(Pascher 1911) Butcher 1967</small>
* ''Cryptomonas'' (''Caerulomonas'') <small>Butcher 1967</small>
* ''Cryptomonas'' (''Eucryptomonas'') <small>Diesing 1850</small>
* ''Cryptomonas'' sect. ''[[Eucryptomonas]]'' <small>(Diesing 1850) Massart 1901</small>
* ''[[Pseudocryptomonas]]'' <small>Bicudo & Tell 1988</small>
}}

'''''Cryptomonas''''' is the name-giving genus of the Cryptomonads established by German biologist [[Christian Gottfried Ehrenberg]] in 1831.<ref name=":0">{{Cite book|title=Illustrated Guide to the Protozoa. 2nd ed.|last=Lee|first=JJ|publisher=Wiley-Blackwell|year=2000|location=New Jersey}}</ref> The algae are common in freshwater habitats and brackish water worldwide and often form blooms in greater depths of lakes.<ref name=":1">{{Cite journal|last1=Choi|first1=Bomi|last2=Son|first2=Misun|last3=Kim|first3=Jong Im|last4=Shin|first4=Woongghi|title=Taxonomy and phylogeny of the genus Cryptomonas (Cryptophyceae, Cryptophyta) from Korea|url=http://koreascience.or.kr/journal/view.jsp?kj=JORHBK&py=2013&vnc=v28n4&sp=307|journal=Algae|volume=28|issue=4|pages=307–330|doi=10.4490/algae.2013.28.4.307|year=2013|doi-access=free}}</ref> The cells are usually brownish or greenish in color and are characteristic of having a slit-like furrow at the anterior.<ref name=":1" />  They are not known to produce any toxins. They are used to feed small [[zooplankton]], which is the food source for small fish in fish farms.<ref name=":1" /> Many species of ''Cryptomonas'' can only be identified by [[DNA sequencing]].<ref name=":2">{{cite journal|author-link1=Laura Wegener Parfrey|last1=Parfrey|first1=Laura Wegener|last2=Lahr|first2=Daniel J. G.|last3=Knoll|first3=Andrew H.|last4=Katz|first4=Laura A.|author-link4=Laura A. Katz|title=Estimating the timing of early eukaryotic diversification with multigene molecular clocks|journal=Proceedings of the National Academy of Sciences of the United States of America|date=August 16, 2011|volume=108|issue=33|pages=13624&ndash;13629|doi=10.1073/pnas.1110633108|pmid=21810989|pmc=3158185|doi-access=free}}</ref><ref name=":3">{{Cite journal|last1=Hoef-Emden|first1=Kerstin|last2=Melkonian|first2=Michael|title=Revision of the Genus Cryptomonas (Cryptophyceae): a Combination of Molecular Phylogeny and Morphology Provides Insights into a Long-Hidden Dimorphism|journal=Protist|language=en|volume=154|issue=3–4|pages=371–409|doi=10.1078/143446103322454130|pmid=14658496|year=2003}}</ref> ''Cryptomonas'' can be found in several marine ecosystems in Australia and South Korea.<ref name=":1" /><ref>{{Cite journal|last=Hill|first=D. R. A.|date=1991-03-01|title=A revised circumscription of Cryptomonas (Cryptophyceae) based on examination of Australian strains|journal=Phycologia|language=EN|volume=30|issue=2|pages=170–188|doi=10.2216/i0031-8884-30-2-170.1}}</ref>

== Etymology ==
''Cryptomonas'' has the meaning of hidden small flagellates from “crypto” and “monas”.<ref>{{Cite web|url=https://www.merriam-webster.com/medical/Monas|title=Medical Definition of MONAS|website=www.merriam-webster.com|language=en|access-date=2017-04-28}}</ref><ref>{{Cite web|url=https://www.merriam-webster.com/dictionary/crypto|title=Definition of CRYPTO|website=www.merriam-webster.com|language=en|access-date=2017-04-28}}</ref>

== Genome structure ==
Species within ''Cryptomonas'' contain four genomes: the [[Cell nucleus|nuclear]], the [[nucleomorph]], the [[plastid]], and [[mitochondrial]] genomes.<ref name=":2" /> The plastid genome contains 118 [[base pair|kilobase pairs]] and is a result of one [[endosymbiosis]] event of ancient [[red alga]].<ref name=":2" /> The study of genome structures of the genus has contributed to the life-history dependent dimorphism of ''Cryptomonas'', which is discussed in details later in the section Dimorphism.

== Functions ==
''Cryptomonas'' are also [[photolithotroph]]s that contribute to oxygenic carbon fixation making them greatly critical to the carbon levels of fresh water environments.<ref name=":3" />

== Reproduction ==
Replication of ''Cryptomonas'' occurs in early summer when fresh water species are also reproducing.<ref name=":3" /> ''Cryptomonas'' replicates via [[mitosis]] that only takes about ten minutes.<ref name=":3" /> Sexual reproduction is not observed in this genus as many other genera of Cryptophytes also do not reproduce sexually.<ref name=":3" />

== Cell structure ==
[[File:Cryptomonas platyuris - 160x (13286242253).jpg|thumb|Cryptomonas platyuris]]
Organisms are asymmetric with a transparent [[Cell membrane|membrane]] on the outside.<ref name=":1" /> The membrane is not ciliated.<ref name=":0" /> ''Cryptomonas'' cells are fairly large; they average about 40 micrometers in size and often take the shape of an oval or ovoid.<ref name=":3" /> There are two [[flagella]] present, yet the two flagella are not equally sized.<ref name=":0" /> One is shorter and curled and the other one is longer and straight.<ref name=":0" /> The two flagella are fixed to the cell by four unique [[microtubule|microtubular]] roots.<ref name=":0" /><ref name=":4">{{Cite journal|last=Roberts|first=Keith R.|date=1984-12-01|title=Structure and Significance of the Cryptomonad Flagellar Apparatus. I. Cryptomonas Ovata (cryptophyta)1|journal=Journal of Phycology|language=en|volume=20|issue=4|pages=590–599|doi=10.1111/j.0022-3646.1984.00590.x|s2cid=84268839|issn=1529-8817}}</ref> In addition, the flagella are lined with small hairs that allow for better movement.<ref name=":1" /> There are also [[contractile vacuole]]s that control the flow of water in and out.<ref name=":0" />

Two boat-shaped plastids are observed in the cells.<ref name=":1" /> In a secondary endosymbiosis event, the [[phagotroph]]ic ancestor of the ''Cryptomonas'' presumably captured a red alga and reduced it to a complex plastid with four envelope membranes.<ref name=":1" /> The [[phycobilisome]]s of the former red algae were reduced until only [[phycoerythrin]] remained.<ref name=":3" /> [[Phycoerythrobilin]], a type of red [[phycobilin]] pigment, is a [[chromophore]] discovered in cyanobacteria, chloroplasts of red algae and some Cryptomonads.<ref name=":3" /> Phycoerythrobilin is present in the [[phycobiliprotein]] phycoerythrin, the terminal acceptor of energy during the process of photosynthesis.<ref>{{Cite journal|last1=Chapman|first1=David J.|last2=Cole|first2=W. J.|last3=Siegelman|first3=Harold W.|date=1967-11-01|title=Structure of phycoerythrobilin|journal=Journal of the American Chemical Society|volume=89|issue=23|pages=5976–5977|doi=10.1021/ja00999a058|issn=0002-7863}}</ref> The phycoerythrin was translocated into the [[thylakoid]] lumen with its chromophore composition altered; subsequently, phycobiliproteins with at least seven different absorption spectra evolved.<ref name=":3" /> ''Cryptomonas'' is distinguished by the purple phycoerythrin 566 as an accessory pigment, which gives the organisms a brownish color in appearance.<ref name=":1" />

== Behaviour ==
''Cryptomonas'' are large in size, grow rather slowly, and are limited in nutrients.<ref name=":3" /> It also migrates between depths of water in order to reach depths that are ideal for photosynthesis and bacteriograzing, as well avoiding organisms that are their predators.<ref name=":3" /> Typically, they are found at depths of up to 102 meters and in a temperature range of -1.4 to 1.5 degrees Celsius. ''Cryptomonas'' seem to grow and survive with little competition.<ref name=":3" /> ''Cryptomonas'' swim actively, and they rotate while moving and sometimes swim in helical motion.<ref name=":5">{{Cite journal|last1=Kaneda|first1=Hisako|last2=Furuya|first2=Masaki|date=1987-05-01|title=Effects of the Timing of Flashes of Light during the Course of Cellular Rotation on Phototactic Orientation of Individual Cells of Cryptomonas|journal=Plant Physiology|volume=84|issue=1|pages=178–181|issn=0032-0889|pmc=1056548|pmid=16665394|doi=10.1104/pp.84.1.178}}</ref>

== Dimorphism ==
Life history-dependent dimorphism was first described in organisms in 1986.<ref name=":3" /> In ''[[Proteomonas]]'', another genus of Cryptophyceae, the two morphs revealed large differences in cell size which apparently led to its discovery and subsequent recognition. ''Cryptomonas'' has been discovered to be another genus that possesses the characteristic of dimorphism.<ref name=":3" />

Traditionally, ''Cryptomonas'' was considered to be 3 separate genera: ''[[Chilomonas]],'' ''Cryptomonas'' and ''[[Campylomonas]]''.<ref name=":3" /> Before further molecular analysis, ''Cryptomonas'' have been characterized by mainly morphological characters, such as cell size, cell shape, number and color of plastids. However, it was still difficult to define ''Cryptomonas'' due to insufficient understanding of morphological characters and less-than adequate visibility of living cells using light microscopy alone to observe the cell structures. Also, laboratories had lacked the condition to detect the different stages of particular organisms.<ref name=":3" />

The furrow-gullet system was used as a standard for organization of genera for many years.<ref name=":1" /> Most other Cryptophyte genera have either furrow or gullet, but ''Cryptomonas'' is one of the genera that possess a combination of the two, creating a furrow-gullet complex.<ref name=":1" /> The furrow-gullet complex is used by the cells to digest food for smaller organisms.<ref name=":4" /> Also, ejectisomes are found to be surrounding the complex.<ref name=":1" /> Previously, different textures of furrow plates are used to classify genera. For example, a furrow plate (extending posteriorly along one side of the ventral furrow-gullet complex) has been described as “scalariform” in ''Campylomonas'' yet “fibrous” in ''Cryptomonas''.<ref name=":1" /> In addition, in ''Cryptomonas'', the inner periplast component consists of polygonal plates. In contrast, in ''Campylomonas'', the inner periplast component is a continuous sheet-like layer.<ref name=":1" />

However, during later research, more evidence of both [[molecular phylogeny]] and morphology has been found to support the claim that the three genera should be considered one single dimorphic genus.<ref name=":3" /> Characters previously used to distinguish ''Cryptomonas'' from ''Campylomonas'' were found to occur together in dimorphic strains, such as the type of [[periplas]]t (polygonal periplast plates versus a continuous periplast sheet), indicating that periplast types relate to different life-history stages of a single taxon.<ref name=":3" /> To evaluate the taxonomic significance of the type of periplast and other characters previously used to distinguish genera and species, molecular phylogenetic analyses have been used to study two nuclear [[ribosomal DNA]] regions (ITS2, partial LSU rDNA) and a nucleomorph ribosomal gene (SSU rDNA).<ref name=":3" /> The results of the phylogenetic study provide molecular evidence for a life history-dependent dimorphism in the genus ''Cryptomonas'': the genus ''Campylomonas'' represents the alternate morph of ''Cryptomonas''. ''Campylomonas'' and ''Chilomonas'' are reduced to synonyms of ''Cryptomonas''.

== Further research ==
In addition to plastids containing phycoerythrobilin, campylomorphs, formerly genera ''Campylomonas'' and ''Chilomonas'', also contain a colorless plastid that lacks photosynthetic pigment: [[leucoplast]].<ref name=":3" />

Since the complete loss of photopigments clearly distinguishes the leukoplastidious cryptophytes from ''Cryptomonas'', the incorporation of “''Chilomonas''” with ''Cryptomonas'' has been highly debatable. Scientists have not yet found out an explanation of how leucoplasts disappear during later life stage and when they disappear.<ref name=":3" />

== Species ==
* ''[[Cryptomonas ampulla]]'' Playfair
* ''[[Cryptomonas anomala]]'' F.E.Fritsch, 1914
* ''[[Cryptomonas appendiculata]]'' Schiller, 1957
* ''[[Cryptomonas baltica]]'' (G.Karsten) Butcher, 1967
* ''[[Cryptomonas borealis]]'' Skuja, 1956
* ''[[Cryptomonas brevis]]'' J.Schiller
* ''[[Cryptomonas commutata]]'' (Pascher) Hoef-Emden, 2007
* ''[[Cryptomonas compressa]]'' Pascher, 1913
* ''[[Cryptomonas croatanica]]'' P.H.Campbell, 1973
* ''[[Cryptomonas curvata]]'' Ehrenberg, 1831
* ''[[Cryptomonas cylindracea]]'' Skuja, 1956
* ''[[Cryptomonas czosnowskii]]'' Kisselev
* ''[[Cryptomonas erosa]]'' Ehrenberg, 1832
* ''[[Cryptomonas gemma]]'' Playfair
* ''[[Cryptomonas gracilis]]'' Skuja
* ''[[Cryptomonas gyropyrenoidosa]]'' Hoef-Emden & Melkonian, 2003
* ''[[Cryptomonas marssonii]]'' Skuja, 1948
* ''[[Cryptomonas maxima]]'' Playfair
* ''[[Cryptomonas mikrokuamosa]]'' R.E.Norris, 1964
* ''[[Cryptomonas nasuta]]'' Pascher
* ''[[Cryptomonas oblonga]]'' Playfair
* ''[[Cryptomonas obovata]]'' Czosnowski, 1948
* ''[[Cryptomonas obovoidea]]'' Pascher, 1913
* ''[[Cryptomonas ovata]]'' Ehrenberg, 1832
* ''[[Cryptomonas paramaecium]]'' (Ehrenberg) Hoef-Emden & Melkonian, 2003
* ''[[Cryptomonas parapyrenoidifera]]'' Skuja
* ''[[Cryptomonas pelagica]]'' H.Lohmann
* ''[[Cryptomonas phaseolus]]'' Skuja, 1948
* ''[[Cryptomonas platyuris]]'' Skuja, 1948
* ''[[Cryptomonas profunda]]'' R.W.Butcher, 1967
* ''[[Cryptomonas prora]]'' W.Conrad & H.Kufferath
* ''[[Cryptomonas pyrenoidifera]]'' Geitler, 1922
* ''[[Cryptomonas rhynchophora]]'' (W.Conrad) Butcher
* ''[[Cryptomonas richei]]'' F.E.Fritsch, 1914
* ''[[Cryptomonas rostrata]]'' Skuja, 1948
* ''[[Cryptomonas splendida]]'' J.Czosnowski
* ''[[Cryptomonas tenuis]]'' Pascher
* ''[[Cryptomonas testacea]]'' P.H.Campbell, 1973
* ''[[Cryptomonas tetrapyrenoidosa]]'' Skuja, 1948
<ref>{{Cite web|url=http://www.algaebase.org/browse/taxonomy/?id=6828|title=Taxonomy Browser :: Algaebase|website=www.algaebase.org|access-date=2017-04-28}}</ref>

== References ==
{{Reflist}}

== External links ==
* [http://tolweb.org/Cryptomonas/97214 Tree of Life: Cryptomonas]

{{Cryptista}}
{{Taxonbar|from=Q1142294}}

[[Category:Cryptista genera]]
[[Category:Taxa named by Christian Gottfried Ehrenberg]]