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Jakobid
Jakobida is an order (sole order in the class Jakobea) of free-living, heterotrophic, flagellar eukaryotes in the clade Discoba. They are small (less than 15 μm), and can be found in aerobic and anaerobic environments. The order Jakobida, believed to be monophyletic, consists of only twenty species at present, and was classified as a group in 1993. There is ongoing research into the mitochondrial genomes of jakobids, which are unusually large and bacteria-like, evidence that jakobids may be important to the evolutionary history of eukaryotes. Molecular phylogenetic evidence suggests strongly that jakobids are most closely related to Heterolobosea and Euglenozoa. Description Jakobids have two flagella, inserted in the anterior end of the cell, and, like other members of order Excavata, have a ventral feeding groove and associated cytoskeleton support. The posterior flagella has a dorsal vane and is aligned within the ventral groove, where it generates a current that the ce ... [...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] |
Jakoba
''Jakoba'' is a genus in the taxon Excavata, and currently has a single described species, ''Jakoba libera'' described by David_J._Patterson, Patterson in 1990, and named in honour of Dutch botanist (Algology, Myology and Lichenology) Jakoba Ruinen. (Previously described ''Jakoba incarcerata'' has been renamed ''Andalucia incarcerata'', and ''Jakoba bahamensis'' /''Jakoba bahamiensis'' is not formally described.) Appearance and characteristics ''Jakoba'' are small bacterivorous zooflagellates (jakobids) found in marine and hypersaline environments. They are free swimming trophic cells with two Flagellum, flagella and range between five and ten micrometers in length. Cells rotate along their longitudinal axis to allow for swimming in straight lines unless deformation and “squirming” occurs due to compression in debris. During feeding, bacteria are removed from the water column by a current created by the posterior flagellum. This current causes the bacteria to collect in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jakobidae
''Jakoba'' is a genus in the taxon Excavata, and currently has a single described species, '' Jakoba libera'' described by Patterson in 1990, and named in honour of Dutch botanist (Algology, Myology and Lichenology) Jakoba Ruinen. (Previously described ''Jakoba incarcerata'' has been renamed '' Andalucia incarcerata'', and '' Jakoba bahamensis'' /'' Jakoba bahamiensis'' is not formally described.) Appearance and characteristics ''Jakoba'' are small bacterivorous zooflagellates ( jakobids) found in marine and hypersaline environments. They are free swimming trophic cells with two flagella and range between five and ten micrometers in length. Cells rotate along their longitudinal axis to allow for swimming in straight lines unless deformation and “squirming” occurs due to compression in debris. During feeding, bacteria are removed from the water column by a current created by the posterior flagellum. This current causes the bacteria to collect in the groove on the righ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stygiellidae
Stygiellidae is a family of free-living marine flagellates belonging to the order Jakobida, a deep-branching lineage within the eukaryotic supergroup Discoba. They are unicellular organisms that commonly inhabit anoxic, sulfide-rich and ammonium-rich marine habitats worldwide. Cell morphology and behavior Members of Stygiellidae are genetically diverse but morphologically similar anaerobic jakobids. The unifying aspect of their appearance is their cristae-lacking mitochondria due to the secondary loss of aerobic metabolism. They resemble jakobid cells, and form two morphotypes: grooved cells, attached to the substrate, with a conspicuous groove; and swimming cells, with a less distinct, narrower groove. Both morphotypes move in a spiral motion, although the swimming cells are faster. It is difficult to distinguish morphological aspects between species due to the variability among cells within the same strain and the similarity between grooved and swimming cells. Ecology and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Histiona
''Histiona'' is a genus of Excavata containing four species. It has a worldwide distribution. It is a Jakobid Jakobida is an order (sole order in the class Jakobea) of free-living, heterotrophic, flagellar eukaryotes in the clade Discoba. They are small (less than 15 μm), and can be found in aerobic and anaerobic environments. The order Jakobida, b .... References Discoba genera Jakobids {{Excavata-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reclinomonas
''Reclinomonas'' is a monotypic genus of jakobid eukaryotes containing the single species ''Reclinomonas americana''.Simpson, A. 2008''Reclinomonas'' Flavin & Nerad 1993. ''Reclinomonas americana'' Flavin & Nerad 1993.Version 05. The Tree of Life Web Project. This organism is a single cell up to 12 micrometers wide. It has two flagella. The cell is in a cup-like lorica which has a stem that attaches to a surface. When the cell reproduces, by undergoing binary fission, one of the two newly split cells produces a new lorica for itself. This protozoan can be found in freshwater. This species was the first jakobid to have its mitochondrial genome sequenced. It contains 97 genes, 62 of them code for proteins.Berg, J. M., et al. Biochemistry.' Edition 6. Macmillan. 2010. pg. 505. Other jakobids have been sequenced since, and the data were similar. It has been described as a member of the Excavata Excavata is an obsolete, extensive and diverse paraphyletic group of unicellular ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stygiella Incarcerata
''Stygiella incarcerata'' is a species of Excavata. Taxonomy ''Stygiella incarcerata'' was originally described to the genus ''Jakoba'' in 2000, but was moved to the newly created genus ''Andalucia Andalusia ( , ; , ) is the southernmost autonomous community in Peninsular Spain, located in the south of the Iberian Peninsula, in southwestern Europe. It is the most populous and the second-largest autonomous community in the country. It i ...'' in 2006. It was transferred again to the new genus '' Stygiella'' in 2015. References Jakobids Discoba species Protists described in 2000 {{Excavata-stub ... [...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] |
Mitochondrion
A mitochondrion () is an organelle found in the cell (biology), cells of most eukaryotes, such as animals, plants and fungi. Mitochondria have a double lipid bilayer, membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is used throughout the cell as a source of chemical energy. They were discovered by Albert von Kölliker in 1857 in the voluntary muscles of insects. The term ''mitochondrion'', meaning a thread-like granule, was coined by Carl Benda in 1898. The mitochondrion is popularly nicknamed the "powerhouse of the cell", a phrase popularized by Philip Siekevitz in a 1957 ''Scientific American'' article of the same name. Some cells in some multicellular organisms lack mitochondria (for example, mature mammalian red blood cells). The multicellular animal ''Henneguya zschokkei, Henneguya salminicola'' is known to have retained mitochondrion-related organelles despite a complete loss of their mitochondrial genome. A large number ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crista
A crista (; : cristae) is a fold in the inner mitochondrial membrane, inner membrane of a mitochondrion. The name is from the Latin for ''crest'' or ''plume'', and it gives the inner membrane its characteristic wrinkled shape, providing a large amount of surface area for chemical reactions to occur on. This aids cellular respiration#Aerobic respiration, aerobic cellular respiration, because the mitochondrion requires oxygen. Cristae are studded with proteins, including ATP synthase and a variety of cytochromes. Background With the discovery of the dual-membrane nature of mitochondria, the pioneers of mitochondrial ultrastructure, ultrastructural research proposed different models for the organization of the mitochondrial inner membrane. Three models proposed were: *Baffle model – According to George Emil Palade, Palade (1953), the mitochondrial inner membrane is convoluted in a baffle-like manner with broad openings towards the intra-cristal space. This model entered most text ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
