Collodictyon
| Collodictyon | |
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| Collodictyon,with nucleus and four flagella (view from the rear) | |
| Scientific classification (incertae sediswithinEukaryota) | |
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| Genus: | Collodictyon Carter1865
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| Type species | |
| Collodictyon triciliatum Carter1865
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| Species | |
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Collodictyonis a genus of single-celled, omnivorouseukaryotesbelonging to the collodictyonids, also known as diphylleids.[1][2]Due to their mix of cellular components, Collodictyonids do not belong to any well-knownkingdom-level grouping of thatdomainand this makes them distinctive from other families.[3][4]Recent research places them in a new 'supergroup' together with rigifilids andMantamonas,with the so-far informal name 'CRuMs'.[5]
Taxonomy and phylogeny
[edit]| Phylogenetic position ofCollodictyonrelative to a few example organisms[1] |
Four species are currently recognised in thisgenus.The type species isCollodictyon triciliatum.A second species—Collodictyon sparsevacuolatum—named by Skuja is also recognised; this species is found infreshwaterin theUnited StatesandEurope.A third speciesCollodictyon sphaericumhas been described but its description is in doubt and reclassified asQuadricilia rotundata(Skuja 1948) Vørs 1992.A fourth species—Collodictyon hongkongense—has been described by Skvortzow but this description is considered inadequate and this species is regarded as being of dubious validity.[6]
- C. hongkongenseSkvortzov 1968
- C. indicumIyengar 1981
- C. sparsevacuolatumSkuja 1956
- C. triciliatumCarter 1865
Along with the genusDiphylleia,this organism appears to be only distantly related to the other eukaryotes.[1][7]They share some morphological features with the species currently placed withinExcavatadue to the fact that the Collodictyon sulcus is similar because it also contains a supporting structure from left and right microtubular roots that line the entirety of the lips of the Sulcus.[8][9]However this lattercladeis considered to bepolyphyleticand in need of resolution (reorganisation into different groups). For this reason inclusion of this genus within the excavates may not assist in understanding its phylogenetic position. They also share similar features as Amoebozoa because the feeding groove ofCollodictyonalso form pseudopods at the base which have a related function to the pseudopods in Amoebozoa.[10]The pseudopods in both Amoebozoa andCollodictyonare used in order to catch prey.
Brugerolle has proposed a family,Collodictyonidaefor this genus andDiphylleia.[8]
Another genus that is related toCollodictyonisSulcomonas.
Scientists speculate that further study ofCollodictyonmay yield insights into the prehistoric beginnings of life hundreds of millions of years ago.[3]Scientists fromNorwayhave been studying a particular type ofCollodictyonfound living in sludge inÅrungen,a lake in the municipality ofÅsinNorway.[3][11]Kamran Shalchian-Tabrizi, the leader of theMicrobial Evolution Research Group(MERG), has claimed that these organisms resemble the basal eukaryote.[3]
Collodictyonids were placed by Cavalier-Smith inVarisulca,[12]but this grouping appears to be paraphyletic.
Description
[edit]The species in this genus range in size from 30 to 50μmin length,[3]can grow broadpseudopodia,and have fourflagella[3]and a ventral feeding groove which divides the organism longitudinally called the Sulcus.[1]They are devoid of cellulosic cell walls,chloroplastsor stigmata. There are two to several contractilevacuoles.
The cell shape is variable but is mostlyobovoidto ellipsoid. The lateral cell margins maybe somewhat angular leading to a broad, truncated rounded apex. This posterior margin narrows posteriorly and either bears 1-3 lobes or is simply broadly rounded. This margin is often pseudopodial.
The nucleus typically lies in the posterior half of the cell.
Themitochondriahave tubularcristae.
Organellescalleddictyosomesare present and arranged in ahorseshoelike shape.[8]
Members of this genus are known to reproduceasexuallythroughcell division.Whethersexual reproductionoccurs is currently unknown.
Collodictyon triciliatumhas four flagella connected to basal bodies, generally of equal length, as long as or slightly longer than the body of Collodictyon.[2]Number one flagellum is connected to a dorsal root, while number two flagellum is connected to a ventral root. Number three and four flagella are on either side of these two and have dorsal roots.
Distribution
[edit]OriginallyCollodictyon triciliatumwas described from the island ofBombayand later in central Europe.[13][14]In Europe this species is found fromSpain[15]toNorway.[1]Collodictyonhas also been reported in North America.[6][14][16]
Feeding
[edit]
The feeding habits of this organism have rarely been studied.
In its feeding habits, Collodictyon is most interesting. When hungry, it can be distinguished frommoribundstages in which all food is extruded by pseudopial projections from the lateral groove or sulcal region... these pseudopodia... function actively whenever the organism is seeking food. At these times when coming in contact withProtozoaoralgaewhich it may use for food, they are wafted to thesulcalregion by the flagella, or else Collodictyon aligns itself alongside of its prey with the pseudopodia in contact.... Both the flagella and the pseudopodia appear sensitive to food stimulus...
— Robert Clinton Rhodes, 1917[17]
Dag Klaveness reported that the creatures are "not sociable" and will cannibalize each other when food is scarce.[3]Collodictyonwill ingest freshwater algae and appears to be unable to survive on a diet of bacteria alone. Curiously the algae remain viable at least for a while after being engulfed. It is possible that the algae are "enslaved".[17]
History
[edit]Collodictyon triciliatumwas originally named by H. J. Carter in 1865.[13] Carter's original species description is as follows:
Pyriform,straight, or slightly bent upon itself,bifid(two-lobed) at the small extremity, presenting at the larger one an indentation, from which spring threecilia.Structure transparent, cancellated, composed of globular cells, with a strongly marked, greenish granule here and there in the triangular spaces between them. Locomotive, swimming by means of the cilia; subpolymorphic, flexible, yielding, capable of assuming a globular form... or one more or less modified by the body it may incept...; enclosing crude material for nourishment in stomachal spaces, and ejecting the refuse, like Amoeba. Provided with a nucleus and contractingvesicles.
— Carter, 1865[14]
In 1917, it was classified as being one of the "simplest and most primitive" type ofPolymastigina.[18]
See also
[edit]
References
[edit]- ^abcdeZhao, Sen; Fabien Burki; Jon Bråte; Patrick Keeling;Dag Klaveness;Kamran Shalchian-Tabrizi (2012-01-06)."Collodictyon – an Ancient Lineage in the Tree of Eukaryotes".Molecular Biology and Evolution.29(6): 1557–68.doi:10.1093/molbev/mss001.ISSN0737-4038.PMC3351787.PMID22319147.
- ^abRhodes, Robert Clinton (29 October 1917).Binary Fission in Collodictyon tricilliatum.Berkeley, California: University of California.
number of flagella is four (page 238 of original book; page 50 of the pdf file). Flagella are equal in length, as long as the body or possibly longer...
- ^abcdefg"Scientists find 'man's remotest relative' in lake sludge".26 April 2012.
- ^Skvortzov, B. V. (1968).On a new species of the genus Collodictyon Carter, a colourless flagellata new to the Hongkong flora.22,451–454.
- ^Brown, Matthew W; Heiss, Aaron A; Kamikawa, Ryoma; Inagaki, Yuji; Yabuki, Akinori; Tice, Alexander K; Shiratori, Takashi; Ishida, Ken-Ichiro; Hashimoto, Tetsuo; Simpson, Alastair; Roger, Andrew (2018-01-19)."Phylogenomics Places Orphan Protistan Lineages in a Novel Eukaryotic Super-Group".Genome Biology and Evolution.10(2): 427–433.doi:10.1093/gbe/evy014.ISSN1759-6653.PMC5793813.PMID29360967.
- ^abMD Guiry in Guiry MD & Guiry GM 2012."Collodictyon HJ Carter, 1865: 289".AlgaeBase. World-wide electronic publication.Galway: National University of Ireland.Retrieved28 April2012.
{{cite web}}:CS1 maint: numeric names: authors list (link) - ^Live Science Strange, Organism Has Unique Roots in the Tree of Life,by Jennifer Welsh, 29 April 2012
- ^abcBrugerolle, Guy; Bricheux G; Philippe H; Coffea G (March 2002). "Collodictyon triciliatumandDiphylleia rotans(=Aulacomonas submarina) form a new family of flagellates (Collodictyonidae) with tubular mitochondrial cristae that is phylogenetically distant from other flagellate groups ".Protist.153(1): 59–70.doi:10.1078/1434-4610-00083.PMID12022276.
- ^Heiss AA, Kolisko M, Ekelund F, Brown MW, Roger AJ, Simpson AGB, Al E (2018-04-04)."Combined morphological and phylogenomic re-examination of malawimonads, a critical taxon for inferring the evolutionary history of Eukaryotes".Royal Society Open Science.Retrieved2021-11-01.
- ^Nishibe, Y., Kawabata, Z., & Nakano, S.-ichi. (2002, September 23).Grazing on microcystis aeruginosa by the heterotrophic flagellate Collodictyon Triciliatum in a hypertrophic pond.Aquatic Microbial Ecology. Retrieved November 1, 2021, fromhttps:// int-res /abstracts/ame/v29/n2/p173-179/.
- ^Yngve Vogt (23 April 2012)."Mankind's remotest relative".Apollon.Original Norwegian press release with pictures of researchers.
- ^Cavalier-Smith, Thomas; Chao, Ema E.; Lewis, Rhodri (2016-06-01)."187-gene phylogeny of protozoan phylum Amoebozoa reveals a new class (Cutosea) of deep-branching, ultrastructurally unique, enveloped marine Lobosa and clarifies amoeba evolution".Molecular Phylogenetics and Evolution.99:275–296.doi:10.1016/j.ympev.2016.03.023.PMID27001604.
- ^abCarter, H.J. (1865)."XXXII.—On the fresh- and salt-water Rhizopoda of England and India".Journal of Natural History.Series 3.15(88): 277–293.doi:10.1080/00222936508681805.ISSN0374-5481.Retrieved11 February2018.
- ^abcRhodes, Robert Clinton (29 October 1917).Binary Fission in Collodictyon tricilliatum.Berkeley, California: University of California.
- ^Cambra Sánchez, J.; Álvarez Cobelas, M.; Aboal Sanjurjo, M. (1988)."Lista florística y bibliográfica de los clorófitos (Chlorophyta) de la Península Ibérica, Islas Baleares e Islas Canarias"(PDF).Asociación Española de Limnología. p. 9.Retrieved28 April2012.[permanent dead link]
- ^Lackey, James B. (1942-01-01). "The Plankton Algae and Protozoa of Two Tennessee Rivers".American Midland Naturalist.27(1): 191–202.doi:10.2307/2421034.ISSN0003-0031.JSTOR2421034.
- ^abRhodes, Robert Clinton (29 October 1917).Binary Fission in Collodictyon tricilliatum.Berkeley, California: University of California.
(page 220 from original book; page 32 from the pdf)... In its feeding habits, Collodictyon is most interesting. When hungry, it can be distinguished from moribund stages in which all food is extruded by pseudopial projections from the lateral groove or sulcal region... these pseudopodia... function actively whenever the organism is seeking food. At these times when coming in contact with Protozoa or algae which it may use for food, they are wafted to the sulcal region by the flagella, or else Collodictyon aligns itself alongside of its prey with the pseudopodia in contact.... Both the flagella and the pseudopodia appear sensitive to food stimulus...
- ^Rhodes, Robert Clinton (29 October 1917).Binary Fission in Collodictyon tricilliatum.Berkeley, California: University of California.
(page 239 of original book; page 51 of pdf file)... Collodictyon is "one of the simplest and most primitive of the Polymastigina"...