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Metamonad
The metamonads are a large group of flagellate amitochondriate microscopic eukaryotes. They include the retortamonads, diplomonads, parabasalids, oxymonads, and a range of more poorly studied taxa, most of which are free-living flagellates. All metamonads are anaerobic (many being aerotolerant anaerobes), and most members of the four groups listed above are symbiotes or parasites of animals, as is the case with ''Giardia lamblia'' which causes diarrhea in mammals. Characteristics A number of parabasalids and oxymonads are found in termite guts, and play an important role in breaking down the cellulose found in wood. Some other metamonads are parasites. These flagellates are unusual in lacking aerobic mitochondria. Originally they were considered among the most primitive eukaryotes, diverging from the others before mitochondria appeared. However, they are now known to have lost aerobic mitochondria secondarily, and retain both organelles and nuclear genes derived ultimate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barthelonid
''Barthelona'' is a genus of anaerobic protists. They are basal eukaryotes closely related to skoliomonads, within the phylum Metamonada. It is a monotypic genus containing the sole species ''Barthelona vulgaris''. Members of this genus are informally known as barthelonids. Description Barthelonids are flagellates, unicellular protists (a type of eukaryote) that use flagella for movement. Their cells measure 6–8 μm in length, and are oval on the dorsal side and flattened on the ventral side. Each cell has two flagella inserted sub-apically and laterally, at an angle of 60° from each other. The anterior flagellum is 1–2 times the cell length, while the posterior flagellum is 3–5 times as large as the cell body, and is slightly acronematic. The nucleus is located in the anterior end of the cell. The cytoplasm usually contains refractile granules. Barthelonids are free-living solitary heterotrophs. They swim or, more rarely, glide slowly. When stationary, they still be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skoliomonas
''Skoliomonas'' is a genus of anaerobic protists closely related to barthelonids, a small group of basal eukaryotes within the phylum Metamonada. It is a monotypic genus containing the sole species ''Skoliomonas litria''. Members of this genus are informally named skoliomonads. They are found inhabiting hypersaline alkaline lakes in Tanzania and North America. Etymology The name ''Skoliomonas'' derives , 'crooked', which refers to the hunched appearance of the cell and the twisted venral groove, and ''μονάς (monas)'' 'unit', a common suffix used for unicellular protists. The specific epithet ''litria'' comes , an alternative form of ''νίτρον (nitron)'', meaning sodium carbonate; the term was used by Herodotus to describe embalming salts used for mummification in Ancient Egypt, harvested from carbonate-rich soda lakes of the Natron Valley. The authors of the species chose the African-specific version of the Ancient Greek word to reflect the African type locality and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxymonad
The Oxymonads (or Oxymonadida) are a group of flagellated protists found exclusively in the intestines of animals, mostly termites and other Xylophagy, wood-eating insects. Along with the similar parabasalid flagellates, they harbor the Symbiosis, symbiotic bacterium, bacteria that are responsible for breaking down cellulose. There is no evidence for presence of Mitochondrion, mitochondria (not even anaerobic mitochondrion-like organelles like hydrogenosomes or mitosomes) in oxymonads and three species have been shown to completely lack any molecular markers of mitochondria. It includes e.g. ''Dinenympha'', ''Pyrsonympha'', ''Oxymonas'', ''Streblomastix'', ''Monocercomonoides'', and ''Blattamonas''. Characteristics Most Oxymonads are around 50 μm in size and have a single cell nucleus, nucleus, associated with four Flagellum, flagella. Their Basal body, basal bodies give rise to several long sheets of microtubules, which form an organelle called an axostyle, but different in st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anaeramoebidae
Anaeramoeba is a genus of anaerobic protists of uncertain phylogenetic position, first described in 2016. Description As the name implies, ''Anaeramoeba'' are anaerobic amoeboid organisms which form a fan-like shape similar to that of '' Flamella''. At least two species can also sometimes assume flagellate forms; with either two or four flagella. They contain double-membrane bound organelles called hydrogenosomes, assumed to be derived from mitochondria, usually associated with colonies of unidentified, rod-shaped bacteria. Discovery and classification ''Anaeramoeba'' specimens were first isolated in 2016, from samples shallow water anoxic ocean sediments collected from around the world. Despite the similarities to ''Flamella'' in both morphology and environment, genetic analyses found that ''Anaeramoeba'' do not belong within Amoebozoa. The precise phylogenetic position was not identified with strong support, and the genus may represent a newly identified, deep-branching g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anaeromonada
Anaeromonadea, also known as Preaxostyla, is a class of excavate protists, comprising the oxymonads, '' Trimastix'', and '' Paratrimastix''. This group is studied as a model system for reductive evolution of mitochondria, because it includes both organisms with anaerobic mitochondrion-like organelles ('' Trimastix'' and '' Paratrimastix''), and those that have completely lost their mitochondria ( oxymonads ''Monocercomonoides ''Monocercomonoides'' is a genus of flagellate Excavata belonging to the order Oxymonadida. It was established by Bernard V. Travis and was first described as those with "polymastiginid flagellates having three anterior Flagellum, flagella and ...'', '' Streblomastix'', and '' Blattamonas''). Phylogeny and Taxonomy Based on the work of Zhang et al. 2015. References External links Tree of Life: Preaxostyla Metamonads {{Excavata-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retortamonad
The retortamonads are a small group of flagellates, most commonly found in the intestines of animals as commensals, although a free-living species called the ''Chilomastix cuspidata'' exists. They are grouped under the taxon Archezoa. They are usually around 5-20 μm in length, and all of their small subunit ribosomal RNA gene sequences are very similar to each other. There are two genera: '' Retortamonas'' with two flagella, and '' Chilomastix'' with four. In both cases there are four basal bodies anterior to a prominent feeding groove, and one flagellum is directed back through the cell, emerging from the groove. The retortamonads lack mitochondria, golgi apparatus The Golgi apparatus (), also known as the Golgi complex, Golgi body, or simply the Golgi, is an organelle found in most eukaryotic Cell (biology), cells. Part of the endomembrane system in the cytoplasm, it protein targeting, packages proteins ..., dictyosomes, and peroxisomes. They are close relatives of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eukaryote
The eukaryotes ( ) constitute the Domain (biology), domain of Eukaryota or Eukarya, organisms whose Cell (biology), cells have a membrane-bound cell nucleus, nucleus. All animals, plants, Fungus, fungi, seaweeds, and many unicellular organisms are eukaryotes. They constitute a major group of Outline of life forms, life forms alongside the two groups of prokaryotes: the Bacteria and the Archaea. Eukaryotes represent a small minority of the number of organisms, but given their generally much larger size, their collective global biomass is much larger than that of prokaryotes. The eukaryotes emerged within the archaeal Kingdom (biology), kingdom Asgard (Archaea), Promethearchaeati and its sole phylum Promethearchaeota. This implies that there are only Two-domain system, two domains of life, Bacteria and Archaea, with eukaryotes incorporated among the Archaea. Eukaryotes first emerged during the Paleoproterozoic, likely as Flagellated cell, flagellated cells. The leading evolutiona ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fornicata
Trichozoa is a group of excavates. "Fornicata" is a similar grouping, but it excludes Parabasalia.Tree at National Institute of Genetics "Eopharyngia" is an even more narrow grouping, including Retortamonadida and Diplomonadida but not Carpediemonas. Further References References External links [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Giardia Lamblia
''Giardia duodenalis'', also known as ''Giardia intestinalis'' and ''Giardia lamblia'', is a flagellated Parasitism, parasitic protozoan microorganism of the genus ''Giardia'' that colonizes the small intestine, causing a diarrheal condition known as giardiasis. The parasite attaches to the intestinal epithelium by a ventral disc (''syn''. sucker (zoology), adhesive disc or sucker), and reproduction, reproduces via Fission (biology)#Binary_fission, binary fission. ''G. duodenalis'' is a non-invasive parasite, that does not spread to other parts of the gastrointestinal tract, but remains confined to the lumen (anatomy), lumen of the small intestine. The parasite exists in two forms; Trophozoite, trophozoites and Microbial cyst, cysts. The microorganism can undergo encystation, transforming into a dormant Microbial cyst, cyst that enables it to survive outside of its Host (biology), host. ''Giardia'' trophozoites are Anaerobic organism, anaerobic, and absorb their nutrients from th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diplomonad
The diplomonads (Greek for "two units") are a group of flagellates, most of which are parasitic. They include ''Giardia duodenalis'', which causes giardiasis in humans. They are placed among the metamonads, and appear to be particularly close relatives of the retortamonads. Morphology Most diplomonads are double cells: they have two nuclei, each with four associated flagella, arranged symmetrically about the body's main axis. Like the retortamonads, they lack both mitochondria and Golgi apparatuses. However, they are now known to possess modified mitochondria, in the case of ''G. duodenalis'', called mitosomes. These are not used in ATP synthesis the way mitochondria are, but are involved in the maturation of iron-sulfur proteins. Possible sexual reproduction in ''Giardia'' The common intestinal parasite ''Giardia duodenalis'' (synonyms ''Giardia lamblia'', ''G. intestinalis'') was once considered to be a descendant of a protist lineage that predated the emergence of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parabasalid
The parabasalids are a group of flagellated protists within the supergroup Excavata. Most of these eukaryotic organisms form a symbiosis, symbiotic relationship in animals. These include a variety of forms found in the intestines of termites and cockroaches, many of which have symbiotic bacteria that help them digest cellulose in woody plants. Other species within this supergroup are known parasites, and include human pathogens. Characteristics The flagella are arranged in one or more clusters near the anterior of the cell. Their basal bodies are linked to parabasal fibers that are associated with a prominent Golgi apparatus, Golgi complex, together forming a parabasal apparatus distinctive to the group. Attachment of a parabasal fiber to the first Golgi cisterna by thin filaments has been reported in ''Tritrichomonas foetus''. Usually they also give rise to a sheet of cross-like microtubules that runs down the center of the cell and in some cases projects past the end. This i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
