Editing Kinetoplastida

{{short description|Flagellated protists belonging to the phylum Euglenozoa}}
{{automatic taxobox
| name = Kinetoplastida
| image = Trypanosoma_cruzi_crithidia.jpeg
| image_caption = ''[[Trypanosoma cruzi]]'' parasites
| taxon = Kinetoplastea
| authority =Honigberg, 1963 emend. Cavalier-Smith, 1981<ref name=Honigberg>{{cite book|author=Honigberg, B. M.|year=1963|chapter=A contribution to systematics of the non-pigmented flagellates.|editor=Ludvík, J. |editor2=Lom, J. |editor3=Vávra J.|title=Progress in Protozoology: proceedings of the first International Congress on protozoology held at Prague|publisher=Academic Press}}</ref><ref>Cavalier-Smith, T. (1981). Eukaryote kingdoms: seven or nine? Biosystems 14, 461–481.</ref>
| subdivision_ranks = Subdivisions
| subdivision =
* ?[[Bordnamonadidae]]
* ?[[Trypanophididae]]
* [[Prokinetoplastina]]
** [[Prokinetoplastida]]
* [[Metakinetoplastina]]
** [[Neobodonida]]
** [[Parabodonida]]
** [[Bodonida]]
** [[Trypanosomatida]]
| synonyms =
* Kinetoplastida <small>Honigberg 1963 emend. Margulis 1974</small>
}}

'''Kinetoplastida''' (or '''Kinetoplastea''', as a [[Class (biology)|class]]) is a group of [[flagellated]] [[protists]] belonging to the [[phylum]] [[Euglenozoa]],<ref name=berman>{{cite book|last1=Berman|first1=Jules J.|title=Taxonomic Guide to Infectious Diseases: Understanding the Biologic Classes of Pathogenic Organisms|date=2012|publisher=Elsevier/Academic Press|location=London|isbn=978-0-12415-895-5|page=96|url=https://books.google.com/books?id=m7vT6i3xmC4C}}</ref><ref name=uniprot>{{cite web|title=Kinetoplastida (kinetoplasts)|url=https://www.uniprot.org/taxonomy/5653|publisher=UniProt Consortium|access-date=22 January 2015}}</ref> and characterised by the presence of a distinctive [[organelle]] called the [[kinetoplast]] (hence the name), a granule containing a large mass of [[DNA]].  The group includes a number of [[parasite]]s responsible for serious diseases in humans and other animals, as well as various forms found in soil and aquatic environments.  The organisms are commonly referred to as "kinetoplastids" or "kinetoplasts".<ref name=tolweb>{{cite web|last=Lukes|first=Julius|title=Kinetoplastida|url=http://tolweb.org/Kinetoplastida/98013|publisher=The Tree of Life Web Project|access-date=10 September 2013|date=2009}}</ref>

The kinetoplastids were first defined by [[Bronislaw M. Honigberg]] in 1963 as the members of the flagellated protozoans.<ref name=Honigberg /> They are traditionally divided into the biflagellate [[Bodonidae]] and uniflagellate [[Trypanosomatidae]]; the former appears to be [[paraphyletic]] to the latter. One family of kinetoplastids, the trypanosomatids, is notable as it includes several genera which are exclusively parasitic. ''[[Bodo (genus)|Bodo]]'' is a typical genus within kinetoplastida, which also includes various common free-living species which feed on [[bacteria]].  Others include ''[[Cryptobia]]'' and the parasitic ''[[Leishmania]]''.

==Taxonomy==

===History===

Honigberg created the taxonomic names Kinetoplastida and Kinetoplastea in 1963.<ref name=Honigberg/> Since then there is no consensus on the use of either of the two as a definite [[taxon]]. Kinetoplastea is more widely used as the class,<ref>{{cite web|title=Kinetoplastea|url=http://eol.org/pages/2910504/overview|website=EOL|access-date=22 January 2015}}</ref><ref>{{cite web|title=Kinetoplastea|url=http://www.marinespecies.org/aphia.php?p=taxdetails&id=562565|publisher=World Register of Marine Species|access-date=22 January 2015}}</ref><ref>{{cite web|title=Kinetoplastea |url=http://zipcodezoo.com/key/protozoa/Kinetoplastea_Class.asp |publisher=ZipcodeZoo |access-date=22 January 2015 |url-status=dead |archive-url=https://web.archive.org/web/20150122171006/http://zipcodezoo.com/key/protozoa/Kinetoplastea_Class.asp |archive-date=22 January 2015 }}</ref><ref>{{cite web|title=Taxon: Class Kinetoplastea |url=http://taxonomicon.taxonomy.nl/TaxonName.aspx?id=198775&src=0 |publisher=The Taxonomicon |access-date=22 January 2015 |url-status=dead |archive-url=https://web.archive.org/web/20150122151926/http://taxonomicon.taxonomy.nl/TaxonName.aspx?id=198775&src=0 |archive-date=22 January 2015 }}</ref><ref>{{cite journal|last1=Moreira|first1=D.|title=An updated view of kinetoplastid phylogeny using environmental sequences and a closer outgroup: proposal for a new classification of the class Kinetoplastea|journal=International Journal of Systematic and Evolutionary Microbiology|date=2004|volume=54|issue=5|pages=1861–1875|doi=10.1099/ijs.0.63081-0|pmid=15388756|doi-access=free}}</ref> while Kinetoplastida is mostly used to designate the [[Order (biology)|order]],<ref name=uniprot/><ref>{{cite web|title=Kinetoplastida|url=http://eol.org/pages/5002/names?all=1|website=EOL|access-date=22 January 2015}}</ref><ref>{{cite web|title=Kinetoplastida |url=http://www.metalife.com/NCBI%20Taxonomy/5653 |website=Metalife |access-date=22 January 2015 |url-status=dead |archive-url=https://web.archive.org/web/20150122153154/http://www.metalife.com/NCBI%20Taxonomy/5653 |archive-date=22 January 2015 }}</ref><ref>{{cite web|title=Kinetoplastida|url=https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?lvl=0&id=5653|publisher=NCBI Taxonomy|access-date=22 January 2015}}</ref> but is also used as a class.<ref name=berman/><ref>{{cite book|last1=Gutierrez|first1=Yezid|title=Diagnostic Pathology of Parasitic Infections with Clinical Correlations|date=2000|publisher=Oxford University Press|location=New York|isbn=978-0-1951214-38|page=63|edition=2}}</ref> [[Lynn Margulis]], who initially accepted Kinetoplastida as an order in 1974, later placed it as a class.<ref>{{cite book|first1=Lynn|last1=Margulis |first2=Michael J.|last2=Chapman |title=Kingdoms & Domains : An Illustrated Guide to the Phyla of Life on Earth|url=https://archive.org/details/fivekingdomsillu00marg_711|url-access=limited|year=2009|publisher=Academic Press/Elsevier|location=Amsterdam|isbn=978-0-12-373621-5|page=[https://archive.org/details/fivekingdomsillu00marg_711/page/n213 158]|edition=4}}</ref> Use of Kinetoplastida as an order also creates confusion as there is already an older name Trypanosomatida Kent, 1880, under which the kinetoplastids are most often placed.<ref>{{cite journal|last1=Deschamps|first1=P.|last2=Lara|first2=E.|last3=Marande|first3=W.|last4=Lopez-Garcia|first4=P.|last5=Ekelund|first5=F.|last6=Moreira|first6=D.|title=Phylogenomic analysis of kinetoplastids supports that trypanosomatids arose from within bodonids|journal=Molecular Biology and Evolution|year=2010|volume=28|issue=1|pages=53–58|doi=10.1093/molbev/msq289|pmid=21030427|doi-access=free}}</ref>

===Classification===

Kinetoplastida is divided into two subclasses - [[Metakinetoplastina]] and [[Prokinetoplastina]].<ref>{{cite journal|last1=Moreira|first1=D|last2=López-García|first2=P|last3=Vickerman|first3=K|title=An updated view of kinetoplastid phylogeny using environmental sequences and a closer outgroup: proposal for a new classification of the class Kinetoplastea|journal=International Journal of Systematic and Evolutionary Microbiology|year=2004|volume=54|issue=Pt 5|pages=1861–1875|doi=10.1099/ijs.0.63081-0|pmid=15388756|doi-access=free}}</ref><ref>{{cite journal|last1=Stevens|first1=JR|title=Kinetoplastid phylogenetics, with special reference to the evolution of parasitic trypanosomes|journal=Parasite|year= 2008|volume= 15|issue= 3|pages= 226–232|doi=10.1051/parasite/2008153226 |pmid=18814685|doi-access=free}}</ref>
* Family ?[[Bordnamonadidae]] <small>Cavalier-Smith 2013</small>
* Family ?[[Trypanophididae]] <small>Poche 1911</small>
* Subclass [[Prokinetoplastina]] <small>Vickerman 2004</small>
** Order [[Prokinetoplastida]] <small>Vickerman 2004</small>
*** Family [[Ichthyobodonidae]] <small>Isaksen et al. 2007</small>
* Subclass [[Metakinetoplastina]] <small>Vickerman 2004</small>
** Order [[Neobodonida]] <small>Vickerman 2004</small>
*** Family [[Rhynchomonadidae]] <small>Cavalier-Smith 2016</small>
*** Family [[Neobodonidae]] <small>Cavalier-Smith 2016</small>
** Order [[Parabodonida]] <small>Vickerman 2004</small>
*** Family [[Parabodonidae]] <small>Cavalier-Smith 2016</small> [Cryptobiaceae <small>Poche 1911</small>; Cryptobiidae <small>Vickerman 1976</small>; Trypanoplasmatidae <small>Hartmann & Chagas 1910</small>]
** Order [[Bodonida]] <small>Hollande 1952 emend. Vickerman 1976</small>
*** Family [[Bodo (excavate)|Bodonidae]] <small>Bütschli 1883</small>
** Order Trypanosomatida <small>Kent 1880 stat. n. Hollande 1952 emend. Vickerman 2004</small>
*** Family Trypanosomatidae <small>Doflein 1901</small> [Trypanomorphidae <small>Woodcock 1906</small>]

==Morphology==
Kinetoplastids are [[eukaryotic]] and possess normal eukaryotic organelles, for example the [[Cell nucleus|nucleus]], mitochondrion, [[golgi apparatus]] and flagellum. Along with these universal structures, kinetoplastids have several distinguishing morphological features such as the kinetoplast, sub-pellicular microtubule array and paraflagellar rod.{{cn|date=March 2023}}

===Mitochondrion and kinetoplast DNA===
{{Main|Kinetoplast}}
The kinetoplast, after which the class is named, is a dense DNA-containing granule within the cell's single mitochondrion, containing many copies of the mitochondrial [[genome]]. The structure is made up of a network of concatenated circular DNA molecules and their related structural proteins along with [[DNA polymerase|DNA]] and [[RNA polymerase]]s. The kinetoplast is found at the base of a cell's flagella and is associated to the flagellum [[basal body]] by a [[Cytoskeleton|cytoskeletal]] structure.{{cn|date=March 2023}}

===Cytoskeleton===
The cytoskeleton of kinetoplastids is primarily made up of [[microtubules]]. These make a highly regular array, the sub-pellicular array, which runs parallel just under the cell surface along the long axis of the cell. Other microtubules with more specialised roles, such as the [[rootlet microtubules]], are also present. Kinetoplastids are capable of forming [[actin]] [[microfilaments]] but their role in the cytoskeleton is not clear. Other cytoskeletal structures include the specialised attachment between the flagellum and the kinetoplast.{{cn|date=March 2023}}

===Flagella===
All kinetoplastids possess at least one flagellum; species in the order trypanosomatida have one and [[bodonida]] have two. In kinetoplastids with two flagella most forms have a leading and trailing flagellum, the latter of which may be attached to the side of the cell. The flagella are used for locomotion and attachment to surfaces. The bases of the flagella are found in a specialised pocket structure which is also the location of the [[cytostome]].{{cn|date=March 2023}}

[[File:2023 Kinetoplastid.svg|thumb|center|upright=2|{{center|'''Representation of a kinetoplastid'''}}{{ordered list|[[Flagellum]]|
Flagellar membrane|
Flagellar axoneme|
Paraflagellar rod|
Flagellar attachment zone|
Flagellar-associated [[Endoplasmic reticulum|ER]]|
Pelicular microtubules|
[[Endosome]], sorts material|
Glycosome|
[[Acidocalcisome]]|
[[Mitochondria|Mitochondrion]], creates [[Adenosine triphosphate|ATP]] (energy) for the cell (discoid cristae)|
[[Cell nucleus|Nucleus]]|
[[Golgi apparatus]], modifies [[protein]]s and sends them out of the cell|
Flagellar pocket collar|
Flagellar pocket|
[[Basal body|Basal bodies]]|
Connecting fibres|
[[Kinetoplast]], DNA-containing granule|
Antipodal site}}]]

==Life cycle==
Kinetoplastids may be free-living or parasitic. The order trypanosomatida is notable as it includes many genera which are exclusively parasitic. Trypanosomatids may have simple life cycles in a single host or more complex ones which progress through multiple differentiation stages in two hosts. Dramatic morphological changes are possible between lifecycle stages. Diseases caused by members of the order trypanosomatida include [[African trypanosomiasis|sleeping sickness]] and [[Chagas disease]], caused by species of ''[[Trypanosoma]]'', and [[leishmaniasis]], caused by species of ''[[Leishmania]]''.<ref name="Scheckenbach 2006">{{cite journal|vauthors=Scheckenbach F, Wylezich C, Mylnikov AP, Weitere M, Arndt H|title=Molecular comparisons of freshwater and marine isolates of the same morphospecies of heterotrophic flagellates|journal=Appl Environ Microbiol|date=October 2006|volume=72|issue=10|pages=6638–6643|doi=10.1128/AEM.02547-05|pmid=17021215|pmc=1610283|bibcode=2006ApEnM..72.6638S }}</ref>

''[[Trypanosoma brucei]]'' can undergo [[meiosis]] as a likely part of a sexual cycle.<ref name="pmid21321215">{{cite journal |vauthors=Peacock L, Ferris V, Sharma R, Sunter J, Bailey M, Carrington M, Gibson W |title=Identification of the meiotic life cycle stage of Trypanosoma brucei in the tsetse fly |journal=Proc. Natl. Acad. Sci. U.S.A. |volume=108 |issue=9 |pages=3671–6 |year=2011 |pmid=21321215 |pmc=3048101 |doi=10.1073/pnas.1019423108 |url=http://psasir.upm.edu.my/25359/1/Identification%20of%20the%20meiotic%20life%20cycle%20stage%20of%20Trypanosoma%20brucei%20in%20the%20tsetse%20fly.pdf|bibcode=2011PNAS..108.3671P |doi-access=free }}</ref><ref name="pmid26027775">{{cite journal |vauthors=Gibson W |title=Liaisons dangereuses: sexual recombination among pathogenic trypanosomes |journal=Res. Microbiol. |volume=166 |issue=6 |pages=459–66 |year=2015 |pmid=26027775 |doi=10.1016/j.resmic.2015.05.005 |url=https://research-information.bristol.ac.uk/en/publications/liaisons-dangereuses(1ecb5cba-da25-4e93-a3cb-b00a0477cb23).html|hdl=1983/1ecb5cba-da25-4e93-a3cb-b00a0477cb23 |hdl-access=free }}</ref>  ''[[Leishmania major]]'' is also capable of a meiotic process that is likely part of a sexual cycle.<ref name="pmid19359589">{{cite journal |vauthors=Akopyants NS, Kimblin N, Secundino N, Patrick R, Peters N, Lawyer P, Dobson DE, Beverley SM, Sacks DL |title=Demonstration of genetic exchange during cyclical development of Leishmania in the sand fly vector |journal=Science |volume=324 |issue=5924 |pages=265–8 |year=2009 |pmid=19359589 |pmc=2729066 |doi=10.1126/science.1169464 |bibcode=2009Sci...324..265A }}</ref>

==Gallery==
<gallery mode="packed" widths="360px" heights="220">
Cryptobia helicis x15,000 Scanning EM.jpg|''[[Cryptobia]]'' sp.
File:Bodo saltans - 400x (13895749563).jpg|''[[Bodo (genus)|Bodo]]'' sp.
File:Trypanosoma sp. PHIL 613 lores.jpg|''[[Trypanosoma]]'' sp.
</gallery>

==References==
<references />

==Bibliography==
* Lumsden, W.H.R. & D.A. Evans (eds.). 1976-1979. ''Biology of the Kinetoplastida'', 2 vols. London: Academic Press.

==External links==
* [http://tolweb.org/Kinetoplastida/98013 Tree of Life: Kinetoplastida]
* [http://www.kinetoplastids.com/ KBD -- Kinetoplastid Biology and Disease]

{{Excavata}}
{{Taxonbar|from1=Q131630|from2=Q21446856}}

[[Category:Euglenozoa classes]]
[[Category:Kinetoplastids| ]]