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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] |
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] |
Diplomonadida
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 mei ... [...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] |
Chilomastix
''Chilomastix'' is a genus of pyriform excavates within the family Retortamonadidae. All species within this genus are flagellated, structured with three flagella pointing anteriorly and a fourth contained within the feeding groove. ''Chilomastix'' also lacks Golgi apparatus and mitochondria but does possess a single nucleus. The genus parasitizes a wide range of vertebrate hosts, but is known to be typically non-pathogenic, and is therefore classified as harmless. The life cycle of ''Chilomastix'' lacks an intermediate host or vector. ''Chilomastix'' has a resistant cyst stage responsible for transmission and a trophozoite stage, which is recognized as the feeding stage. ''Chilomastix mesnili'' is one of the more studied species in this genus due to the fact it is a human parasite. Therefore, much of the information on this genus is based on what is known about this one species. History of knowledge The nomenclature of this genus has been under much dispute throughout history ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flagellate
A flagellate is a cell or organism with one or more whip-like appendages called flagella. The word ''flagellate'' also describes a particular construction (or level of organization) characteristic of many prokaryotes and eukaryotes and their means of motion. The term presently does not imply any specific relationship or classification of the organisms that possess flagella. However, several derivations of the term "flagellate" (such as " dinoflagellate" and " choanoflagellate") are more formally characterized. Form and behavior 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 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 flage ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flagellates
A flagellate is a cell or organism with one or more whip-like appendages called flagellum, flagella. The word ''flagellate'' also describes a particular construction (or level of organization) characteristic of many prokaryotes and eukaryotes and their means of motion. The term presently does not imply any specific relationship or classification of the organisms that possess flagella. However, several Morphological derivation, derivations of the term "flagellate" (such as "dinoflagellate" and "choanoflagellate") are more formally characterized. Form and behavior 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 a cytostome or mouth, where food is Ingestion, ingested. Flagella role in classifying eukaryotes. Among protoctists and microscopic animals, a flagellate is an organism with one or more flagella. So ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retortamonas
''Retortamonas'' is a genus of flagellated excavates. It is one of only two genera belonging to the family Retortamonadidae along with the genus ''Chilomastix''. Martinez-Diaz, R. A., Castro, A. T., Herrera, S. and Ponce, F. 2001: First Report of the Genus Retortamonas (Sarcomastigophora: Retortamonadidae) in Birds. Memórias do Instituto Oswalda Cruz, 96(7), 961-963. doi: https://doi.org/10.1590/S0074-02762001000700013 The genus parasitizes a large range of hosts including humans.Hendarto, J., Mizuno, T., Hidayati, A. P.N., Rozi, I. E., Asih, P. B.S., Syafruddin, D., Yashikawa, H., Matsubayashi, M. and Tokoro, M. 2018: Three monophyletic clusters in Retortamonas species isolated from vertebrates. Parasitology International 69, 93-98. doi: https://doi.org/10.1016/j.parint.2018.12.004 Species within this genus are considered harmless commensals which reside in the intestine of their host.Kawamura, O., Kon, Y., Naganuma, A., Iwami, T., Maruyama H., Yamada, T., Sonobe, K., Horiko ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexamita
''Hexamita'' is a genus of parasitic diplomonads. It is related to ''Giardia''. ''H. columbae'' and ''H. meleagridis'' live in the intestines of birds. ''H. muris'' and ''H. pitheci'' live in the intestines of mammals. ''H. salmonis'' and ''H. truttae'' live in the intestines of fish. Species in the Hexamita family are most commonly spread through fecal matter. The genus also includes the species '' Hexamita inflata''. It is believed that ''Hexamita'' parasites are one possible cause for head and lateral line erosion Head and lateral line erosion, (HLLE) or hole-in-the-head (HITH) is a disease in fish. Chronic ulcerative dermatopathy or chronic erosive dermatopathy are symptoms of similar conditions with different etiology. Symptoms HLLE begins as small pits ... ("hole-in-the-head disease") in aquarium fishes. References External links * http://medical-dictionary.thefreedictionary.com/Hexamita * * http://www.lexic.us/definition-of/Hexamita Metamonads Metamonad ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Giardia
''Giardia'' ( or ) is a genus of anaerobic flagellated protozoan parasites of the phylum Metamonada that colonise and reproduce in the small intestines of several vertebrates, causing the disease giardiasis. Their life cycle alternates between a binucleated motile trophozoite and an infective, metabolically inert, environmentally resistant tetranucleate cyst. Cysts are transmitted between hosts through the fecal-oral route, contaminated water and/or food. ''Giardia'' were first seen by the Dutch microscopist Antonie van Leeuwenhoek in 1681 under the light microscope. The genus is named after French zoologist Alfred Mathieu Giard. Characteristics ''Giardia'' trophozoites are 12–15 μm long and 5–9 μm wide and have a shape of a pear bisected lengthwise. Like other diplomonads, ''Giardia'' has two transcriptionally operational nuclei that contain an equal number of well-defined chromosomes and replicate synchronously with the cell division. The cytoskeleton of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eukaryota
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] |
Excavata
Excavata is an obsolete, extensive and diverse paraphyletic group of unicellular Eukaryota. The group 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 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 Eugleno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
