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27-604: Euglenozoa are a large group of flagellate Discoba . They include a variety of common free-living species, as well as a few important parasites, some of which infect humans. Euglenozoa are represented by four major groups, i.e., Kinetoplastea , Diplonemea , Euglenida , and Symbiontida . Euglenozoa are unicellular, mostly around 15–40 μm (0.00059–0.00157 in) in size, although some euglenids get up to 500 μm (0.020 in) long. Most euglenozoa have two flagella, which are inserted parallel to one another in an apical or subapical pocket. In some these are associated with

54-427: A green alga , captured long ago in an endosymbiosis by a basal euglenozoan. Reproduction occurs exclusively through cell division. During mitosis , the nuclear membrane remains intact, and the spindle microtubules form inside of it. The group is characterized by the ultrastructure of the flagella. In addition to the normal supporting microtubules or axoneme , each contains a rod (called paraxonemal ), which has

81-613: A cytostome or mouth, used to ingest bacteria or other small organisms. This is supported by one of three sets of microtubules that arise from the flagellar bases; the other two support the dorsal and ventral surfaces of the cell. Some other euglenozoa feed through absorption, and many euglenids possess chloroplasts , the only eukaryotes outside Diaphoretickes to do so without performing kleptoplasty , and so obtain energy through photosynthesis . These chloroplasts are surrounded by three membranes and contain chlorophylls A and B , along with other pigments, so are probably derived from

108-506: A cytostome or mouth, where food is ingested . Flagella role in classifying eukaryotes . Among protoctists and microscopic animals , a flagellate is an organism with one or more flagella. Some cells in other animals may be flagellate, for instance the spermatozoa of most animal phyla. Flowering plants do not produce flagellate cells, but ferns , mosses , green algae , and some gymnosperms and closely related plants do so. Likewise, most fungi do not produce cells with flagellae, but

135-413: A dual feeding technique. It can swallow prey whole, pulling large flagellates through the cytostome, in a manner similar to that proposed by Brenda Nisbet. However, it can also choose a more elaborate style of attack. Sometimes, it will press its cytostome against its prey, and then move the rod-organ up and down, using a rasping motion to chew a hole in its victim's cell membrane. After consuming some of

162-540: A flagellate by Félix Dujardin , who created the genus in 1842, giving it the name Pyronema , for its pyriform (pear-shaped) body. However, because that name had already been applied to a genus of fungi, he amended the genus to Peranema , formed from the Greek πέρα (a leather purse or sack ) and νήμα (a thread ). Unfortunately, this name had also been claimed earlier, for a genus of ferns first collected in Nepal. As

189-651: A peculiar type of flagellate/ amoeboid organization, in which cells may present flagella and pseudopods , simultaneously or sequentially, while the helioflagellates (e.g., the cercozoan heliomonads/dimorphids , the stramenopile pedinellids and ciliophryids ) have a flagellate/ heliozoan organization. Peranema See text Peranema is a genus of free-living phagotrophic euglenids (Euglenida; Euglenozoa; Excavata ). There are more than 20 nominal species, varying in size between 8 and 200 micrometers. Peranema cells are gliding flagellates found in freshwater lakes, ponds and ditches, and are often abundant at

216-486: A result, botanists, following the International Code of Botanical Nomenclature , customarily refer to the protist Peranema as Pseudoperanema ; whereas protozoologists, following the International Code of Zoological Nomenclature , have continued to call the genus by the name Dujardin gave it. Peranema' s basic anatomy is that of a typical euglenid. The cell is spindle or cigar-shaped, somewhat pointed at

243-457: A taxonomical distinction between colorless uniflagellates that live by phagotrophy ( Peranema and Astasia ) and the green uniflagellates that photosynthesize ( Euglena ). This distinction was generally abandoned after the publication, in 1952, of a major revision of the euglenoids. In 1997, a combined morphological and molecular analysis of certain euglenoids identified Peranama trichophorum, Euglena gracilis and Khawkinea quartana as

270-445: A tubular structure in one flagellum and a latticed structure in the other. Based on this, two smaller groups have been included here: the diplonemids and Postgaardi . Historically, euglenozoans have been treated as either plants or animals, depending on whether they belong to largely photosynthetic groups or not. Hence they have names based on either the International Code of Nomenclature for algae, fungi, and plants (ICNafp) or

297-417: Is not gliding or swimming (poorly), Peranema can move by metaboly, progressing with wavelike contractions of the body, reminiscent of peristalsis . At the anterior of the cell, there is a narrow aperture, opening into a flask-shaped "reservoir", from which the organism's two flagella emerge. At the bottom of this reservoir lie the basal bodies (centrioles) from which the flagella extend. One flagellum

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324-504: Is relatively long and conspicuous, and when the Peranema is gliding it is held stiffly in front. At the tip of the flagellum, a short segment beats and flails in a rhythmic manner, possibly as a mechanism for detecting and contacting potential prey. Peranama usually glides belly-down, without rotating. The second flagellum is difficult to see with bright field microscopy, and was entirely overlooked by early observers. It emerges from

351-580: The International Code of Zoological Nomenclature (ICZN). For example, one family has the name Euglenaceae under the ICNafp and the name Euglenidae under the ICZN. As another example, the genus name Dinema is acceptable under the ICZN, but illegitimate under the ICNafp, as it is a later homonym of an orchid genus, so that the synonym Dinematomonas must be used instead. The Euglenozoa are generally accepted as monophyletic. They are related to Percolozoa ;

378-489: The protoplasm , the Peranema may then insert its large flagellum into the hole, using it to churn up the contents of the cell so that they may be more easily sucked out. This continues until nothing is left of the prey but the tattered remnants of its pellicle. When Dujardin created the genus Peranema in 1841, he was unable to detect the second flagellum and classified it with other ostensibly uniflagellate "Eugléniens," Astasia and Euglena . In 1881 Georg Klebs drew

405-479: The anterior end. It has a pellicle with parallel finely-ridged proteinaceous strips underlain by microtubules arranged in a helical fashion around the body. With this type of pellicle, which is shared by many euglenids, the spiraling microtubular strips are able to slide past one another, giving the organism an extremely plastic and changeable body shape. This permits a type of squirming motility, sometimes referred to as "euglenoid movement" or "metaboly". When it

432-489: The anterior end. The use of this "rod-organ" in feeding has attracted considerable scholarly interest. Some early researchers speculated that it might assist Peranema in tearing up and consuming its food; while others held that it was actually a tubular construction, serving as a cytopharynx . In 1950, Y. T. Chen accurately identified it as a structure separate from the reservoir, which could be used by Peranama to cut and pierce its prey. Brenda Nisbet questioned this, on

459-410: The bottom of stagnant pools rich in decaying organic material. Although they belong to the class Euglenoidea , and are morphologically similar to the green Euglena , Peranema have no chloroplasts , and do not conduct autotrophy . Instead, they capture live prey, such as yeast, bacteria and other flagellates, consuming them with the help of a rigid feeding apparatus called a "rod-organ." Unlike

486-409: The front." Müller named it Vibrio strictus , placing it among the "long-necked" infusoria, along with Lacrymaria olor and Dileptus . The species Peranema trichophorum was seen and described in 1838 by C.G. Ehrenberg , who, like Müller before him, took the flagellum for a necklike extension of the body, and placed it in the ciliate genus Trachelius . Peranema was correctly identified as

513-502: The green euglenids, they lack both an eyespot (stigma), and the paraflagellar body (photoreceptor) that is normally coupled with that organelle . However, while Peranema lack a localized photoreceptor, they do possess the light-sensitive protein rhodopsin , and respond to changes in light with a characteristic "curling behaviour." The earliest record of a Peranema is in O.F. Müller 's Animalcula Infusoria of 1786, which describes an "elongated linear" creature, "stretched out at

540-433: The grounds that, when examined closely with an electron microscope, the rod-organ is blunt, and therefore an improbable instrument for either cutting or piercing. Since the rod-organ had been seen to move back and forth during feeding, Nisbet argued that its primary function is to create suction, drawing prey into the cytostome . In 1997, Richard Triemer returned to the subject, to confirm Chen's opinion that Peranema has

567-599: The group Sarcomastigophora . The autotrophic flagellates were grouped similarly to the botanical schemes used for the corresponding algae groups. The colourless flagellates were customarily grouped in three groups, highly artificial: Presently, these groups are known to be highly polyphyletic . In modern classifications of the protists, the principal flagellated taxa are placed in the following eukaryote groups, which include also non-flagellated forms (where "A", "F", "P" and "S" stands for autotrophic, free-living heterotrophic, parasitic and symbiotic, respectively): Although

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594-667: The major consumers of primary and secondary production in aquatic ecosystems - consuming bacteria and other protists. An overview of the occurrence of flagellated cells in eukaryote groups, as specialized cells of multicellular organisms or as life cycle stages, is given below (see also the article flagellum ): In older classifications, flagellated protozoa were grouped in Flagellata (= Mastigophora ), sometimes divided into Phytoflagellata (= Phytomastigina, mostly autotrophic) and Zooflagellata (= Zoomastigina, heterotrophic). They were sometimes grouped with Sarcodina (ameboids) in

621-564: The primitive fungal chytrids do. Many protists take the form of single-celled flagellates. Flagella are generally used for propulsion . They may also be used to create a current that brings in food. In most such organisms, one or more flagella are located at or near the anterior of the cell (e.g., Euglena ). Often there is one directed forwards and one trailing behind. Many parasites that affect human health or economy are flagellates in at least one stage of life cycle, such as Naegleria , Trichomonas and Plasmodium . Flagellates are

648-438: The review by Kostygov et al. (2021): Ichthyobodonidae Perkinselidae Allobodonidae Neobodonidae Rhynchomonadidae Cryptobiidae Trypanoplasmatidae Bodonidae Flagellate Flagella in eukaryotes are supported by microtubules in a characteristic arrangement, with nine fused pairs surrounding two central singlets. These arise from a basal body . In some flagellates, flagella direct food into

675-420: The same reservoir as the larger propulsive flagellum, but turns toward the posterior. It does not sit freely, like the trailing flagella of Dinema and Entosiphon , but adheres to the outside of the cell membrane, in a groove along its ventral surface. Next to the reservoir, lies Peranema' s highly developed feeding apparatus, a cytostomal sac supported on one side by a pair of rigid rods, fused together at

702-479: The taxonomic group Flagellata was abandoned, the term "flagellate" is still used as the description of a level of organization and also as an ecological functional group . Another term used is "monadoid", from monad . as in Monas , and Cryptomonas and in the groups as listed above. The amoeboflagellates (e.g., the rhizarian genus Cercomonas , some amoebozoan Archamoebae , some excavate Heterolobosea ) have

729-932: The two share mitochondria with disk-shaped cristae , which only occurs in a few other groups. Both probably belong to a larger group of eukaryotes called the Excavata . This grouping, though, has been challenged. The phylogeny based on the work of Cavalier-Smith (2016): Hemistasiidae Eupelagonemidae Diplonemidae Ichthyobodonidae Rhynchobodo Neobodonidae Parabodonidae Bodonidae Trypanosomatidae Bihospitidae Postgaardidae Calkinsiidae Entosiphonidae Serpenomonadidae Decastavidae Keelungiidae Sphenomonadidae Petalomonadidae Lentomonadidae Ploeotiidae   Peranemidae Anisonemidae Neometanemidae Distigmidae Astasiidae Teloproctidae   Rapazidae Eutreptiaceae Euglenamorphaceae Phacaceae Euglenaceae A consensus phylogeny following

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