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32-560: Bodo ( / ˈ b oʊ d oʊ / ) is a genus of microscopic kinetoplastids , flagellate excavates first described in 1831 by Christian Gottfried Ehrenberg . The genus is small, as it has recently been redefined to include only four species. Bodo includes free-living, phagotrophic organisms that can be found in many marine and freshwater environments as well as some terrestrial environments. Being phagotrophic, Bodo feeds on bacteria and other microorganisms that it finds while swimming through its water-based habitats. The swimming-like movement
64-571: A class ) is a group of flagellated protists belonging to the phylum Euglenozoa , 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 parasites 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". The kinetoplastids were first defined by Bronislaw M. Honigberg in 1963 as
96-484: A monophyletic group. Phylogenetic analyses often do not place malawimonads on the same branch as the other Excavata. Excavates were thought to include multiple groups: Euglenozoa and Heterolobosea (Percolozoa) or Eozoa (as named by Cavalier-Smith ) appear to be particularly close relatives, and are united by the presence of discoid cristae within the mitochondria (Superphylum Discicristata ). A close relationship has been shown between Discicristata and Jakobida ,
128-545: A class. 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. Kinetoplastida is divided into two subclasses - Metakinetoplastina and Prokinetoplastina . Kinetoplastids are eukaryotic and possess normal eukaryotic organelles, for example the nucleus , mitochondrion, golgi apparatus and flagellum. Along with these universal structures, kinetoplastids have several distinguishing morphological features such as
160-650: A conspicuous ventral feeding groove with a characteristic ultrastructure , supported by microtubules —the "excavated" appearance of this groove giving the organisms their name. However, various groups that lack these traits are considered to be derived excavates based on genetic evidence (primarily phylogenetic trees of molecular sequences). The Acrasidae slime molds are the only excavates to exhibit limited multicellularity. Like other cellular slime molds , they live most of their life as single cells, but will sometimes assemble into larger clusters. Excavate relationships were always uncertain, suggesting that they are not
192-419: A flagellar pocket, a looped mitochondria, and a nucleus. Near the kinetoplast, eight microtubules are present which are responsible for supporting the cytopharynx. These microtubules are thought to be involved in ingestion as discussed by Mitchell et al. in 1988, however it remains unconfirmed if they play an active role. The looped mitochondria takes up a large amount of the internal volume of the cell and contain
224-485: A narrow longitudinal groove down one side of the cell. The ancyromonad groove is not used for "suspension feeding", unlike in "typical excavates" (e.g. malawimonads, jakobids, Trimastix , Carpediemonas , Kiperferlia , etc). Ancyromonads instead capture prokaryotes attached to surfaces. The phylogenetic placement of ancyromonads is poorly understood (in 2020), however some phylogenetic analyses place them as close relatives of malawimonads. The conventional explanation for
256-773: A phylogenetic tree with the metamonad Parabasalia as basal Eukaryotes. Discoba and the rest of the Eukaryota appear to have emerged as sister taxon to the Preaxostyla, incorporating a single alphaproteobacterium as mitochondria by endosymbiosis. Thus the Fornicata are more closely related to e.g. animals than to Parabasalia. The rest of the Eukaryotes emerged within the Excavata as sister of the Discoba; as they are within
288-409: Is facilitated by the two unequal flagella that Bodo possesses which arise from an anteriorly located flagellar pocket. Bodo is roughly bean-shaped and is often missed in samples from water or terrestrial environments due to its small size. The genus was originally described in 1831 by Christian Gottfried Ehrenberg as having an ovoid body, a very short tail, transparent and able to show the colour of
320-523: Is found at the base of a cell's flagella and is associated to the flagellum basal body by a cytoskeletal structure. 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
352-490: Is the only genus in the family Bodonidae making it a homogeneous grouping, however, as more studying is done on the species, more changes are likely to arise. It took 130 years to reach this point as even after the use of multiple gene analysis, there are still big arguments over the placement of certain species in the genus. In nature, Bodo is found in marine or fresh water and in terrestrial environments that have high levels of moisture, for example dung. Bodo sits close to
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#1732787099423384-601: The Bodo saltans virus (BsV), the most abundant giant viruses in the ocean. Different strains of the virus are only able to infect either specific species, or in the case of Bodo saltans , even particular strains of that very heterogeneous taxon. Bodo is a microscopic, biflagellated, kidney-shaped, single celled organism with the largest cells being 8 μm in length and 5 μm wide. Some of the smaller organisms can be as little as 3 μm in length and 2 μm wide. The organisms are transparent, but due to their uptake of photosynthetic bacteria
416-402: The bodonids, which led to the shrinking of the genus Bodo as most of its species were transferred into other genera. Bodo was placed into a new order, Eubodonida , and during this switch, the original 149 species were whittled down to just 4. Since 2002, 11 new species have been added to the genus, but 9 of those are seen as controversial. After 130 years, Bodo has been refined and now
448-412: The bottom of the food net of which it is a part. As phagotrophs, Bodo feed on bacteria by ingestion which can cause a change in the organisms colour as Bodo is transparent. Often the bacteria are phototrophic, which means that Bodo are part of the second layer of food nets as they lack the ability to produce their own energy. Several members of the genus Bodo are afflicted by a giant virus known as
480-590: 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 . 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
512-629: The cells are arranged (they have a distinctive ultrastructural identity ). They are considered to be a basal flagellate lineage. On the basis of phylogenomic analyses, the group was shown to contain three widely separated eukaryote groups, the discobids, metamonads, and malawimonads. A current view of the composition of the excavates is given below, indicating that the group is paraphyletic. Except for some Euglenozoa , all are non- photosynthetic . Most excavates are unicellular, heterotrophic flagellates. Only some Euglenozoa are photosynthetic. In some (particularly anaerobic intestinal parasites),
544-412: The circumbuccal lappets, which lie just below the cell membrane. The circumbuccal lappets then coil around the membrane to ingest the bacteria into the buccal cavity where they can then be transported to the cytopharynx. At the cytopharynx, the bacteria are packaged into food vacuoles which allows for digestion and storage. Within the cell, Bodo saltans also contains a contractile vacuole, a kinetoplast,
576-400: The cytoskeleton is not clear. Other cytoskeletal structures include the specialised attachment between the flagellum and the kinetoplast. 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
608-400: The food that it ingests. Ehrenberg also described the type species, Bodo saltans , as being green, but this was later refuted as it was discovered that the green colouration came from the photosynthetic bacteria that it ingests. In 1988, it was found that Bodo is a phagotroph that feed on bacteria of many kinds, some bacteria are more appealing than others. In 2002, Simpson et al. subdivided
640-417: The kinetoplast, a large network of circular DNA. Even after the recent redefinition of the genus Bodo , Bodo saltans contains an immense genetic diversity, and it is likely that that species will have to be split further. Other species in the genus have not been studied molecularly. Kinetoplast DNA (kDNA), is made up of thousands of circular pieces of DNA that are all required in order to correctly replicate
672-423: The kinetoplast, sub-pellicular microtubule array and paraflagellar rod. 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 and RNA polymerases . The kinetoplast
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#1732787099423704-745: The latter having tubular cristae like most other protists, and hence were united under the taxon name Discoba , which was proposed for this supposedly monophyletic group. Metamonads are unusual in not having classical mitochondria—instead they have hydrogenosomes , mitosomes or uncharacterised organelles. The oxymonad Monocercomonoides is reported to have completely lost homologous organelles. There are competing explanations. The malawimonads have been proposed to be members of Excavata owing to their typical excavate morphology, and phylogenetic affinity to other excavate groups in some molecular phylogenies. However, their position among eukaryotes remains elusive. Ancyromonads are small free-living cells with
736-492: The members of the flagellated protozoans. 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 is a typical genus within kinetoplastida, which also includes various common free-living species which feed on bacteria . Others include Cryptobia and
768-415: The mitochondria have been greatly reduced. Some excavates lack "classical" mitochondria , and are called "amitochondriate", although most retain a mitochondrial organelle in greatly modified form (e.g. a hydrogenosome or mitosome ). Among those with mitochondria, the mitochondrial cristae may be tubular, discoidal , or in some cases, laminar. Most excavates have two, four, or more flagella . Many have
800-436: The often resemble a green grape. Bodo includes free-living organisms with the ability to also attach themselves to a substrate using the tip of their longer flagellum. The normal function of this flagellum is locomotion, but the attachment occurs to allow feeding currents to be created. During feeding, the shorter of the two flagella, which usually has mastigonemes attached, is used in a sweeping motion to move bacteria towards
832-480: The order trypanosomatida include sleeping sickness and Chagas disease , caused by species of Trypanosoma , and leishmaniasis , caused by species of Leishmania . Trypanosoma brucei can undergo meiosis as a likely part of a sexual cycle. Leishmania major is also capable of a meiotic process that is likely part of a sexual cycle. Excavata Excavata is an extensive and diverse but paraphyletic group of unicellular Eukaryota . The group
864-472: The organism. These circular genes give rise to a very unique mitochondrial genome as some of the genes are not present in a completed form with fragments being located on multiple circles. This strange sorting of kDNA leads to an increase in difficulty when trying to create phylogenetic trees using kDNA. This Excavata -related article is a stub . You can help Misplaced Pages by expanding it . Kinetoplastida Kinetoplastida (or Kinetoplastea , as
896-439: The origin of the Eukaryotes is that a heimdallarchaeian or another Archaea acquired an alphaproteobacterium as an endosymbiont , and that this became the mitochondrion , the organelle providing oxidative respiration to the eukaryotic cell. Caesar al Jewari and Sandra Baldauf argue instead that the Eukaryotes possibly started with an endosymbiosis event of a Deltaproteobacterium or Gammaproteobacterium , accounting for
928-575: The otherwise unexplained presence of anaerobic bacterial enzymes in Metamonada. The sister of the Preaxostyla within Metamonada represents the rest of the Eukaryotes which acquired an Alphaproteobacterium. In their scenario, the hydrogenosome and mitosome , both conventionally considered "mitochondrion-derived organelles", would predate the mitochondrion, and instead be derived from the earlier symbiotic bacterium. In 2023, using molecular phylogenetic analysis of 186 taxa, Al Jewari and Baldauf proposed
960-445: The parasitic Leishmania . Honigberg created the taxonomic names Kinetoplastida and Kinetoplastea in 1963. 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, while Kinetoplastida is mostly used to designate the order , but is also used as a class. Lynn Margulis , who initially accepted Kinetoplastida as an order in 1974, later placed it as
992-425: The same clade but are not cladistically considered part of the Excavata yet, the Excavata are in this analysis highly paraphyletic. Hodarchaeales Parabasalia Fornicata Preaxostyla Jakobida Heterolobosea Euglenozoa and allies Amorphea (inc. animals, fungi) SAR Archaeplastida (inc. plants) The Anaeramoeba are associated with Parabasalia, but could turn out to be more basal as
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1024-471: Was first suggested by Simpson and Patterson in 1999 and the name latinized and assigned a rank by Thomas Cavalier-Smith in 2002. It contains a variety of free-living and symbiotic protists, and includes some important parasites of humans such as Giardia and Trichomonas . Excavates were formerly considered to be included in the now obsolete Protista kingdom. They were distinguished from other lineages based on electron-microscopic information about how
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