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Placozoa
The Placozoa are a basal form of marine free-living (non-parasitic) multicellular organism. They are the simplest in structure of all animals. Three genera have been found: the classical '' Trichoplax adhaerens'', '' Hoilungia hongkongensis'', and '' Polyplacotoma mediterranea'', where the last appears most basal. The last two have been found only since 2017. Although the Placozoa were first discovered in 1883 by the German zoologist Franz Eilhard Schulze (1840–1921) and since the 1970s more systematically analyzed by the German protozoologist Karl Gottlieb Grell (1912–1994), a common name does not yet exist for the taxon; the scientific name means "flat animals". Biology ''Trichoplax'' is a small, flattened, animal around across. An amorphous multi-celled body, analogous to a single-celled '' Amoeba'', it has no regular outline, although the lower surface is somewhat concave, and the upper surface is always flattened. The body consists of an outer layer of simple epit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Placozoan Anatomy
The Placozoa are a basal form of marine free-living (non-parasitic) multicellular organism. They are the simplest in structure of all animals. Three genera have been found: the classical ''Trichoplax adhaerens'', '' Hoilungia hongkongensis'', and '' Polyplacotoma mediterranea'', where the last appears most basal. The last two have been found only since 2017. Although the Placozoa were first discovered in 1883 by the German zoologist Franz Eilhard Schulze (1840–1921) and since the 1970s more systematically analyzed by the German protozoologist Karl Gottlieb Grell (1912–1994), a common name does not yet exist for the taxon; the scientific name means "flat animals". Biology ''Trichoplax'' is a small, flattened, animal around across. An amorphous multi-celled body, analogous to a single-celled ''Amoeba'', it has no regular outline, although the lower surface is somewhat concave, and the upper surface is always flattened. The body consists of an outer layer of simple epithel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Placozoa
The Placozoa are a basal form of marine free-living (non-parasitic) multicellular organism. They are the simplest in structure of all animals. Three genera have been found: the classical '' Trichoplax adhaerens'', '' Hoilungia hongkongensis'', and '' Polyplacotoma mediterranea'', where the last appears most basal. The last two have been found only since 2017. Although the Placozoa were first discovered in 1883 by the German zoologist Franz Eilhard Schulze (1840–1921) and since the 1970s more systematically analyzed by the German protozoologist Karl Gottlieb Grell (1912–1994), a common name does not yet exist for the taxon; the scientific name means "flat animals". Biology ''Trichoplax'' is a small, flattened, animal around across. An amorphous multi-celled body, analogous to a single-celled '' Amoeba'', it has no regular outline, although the lower surface is somewhat concave, and the upper surface is always flattened. The body consists of an outer layer of simple epit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trichoplax Adhaerens
''Trichoplax adhaerens'' is one of the three named species in the phylum Placozoa. The others are '' Hoilungia hongkongensis'' and '' Polyplacotoma mediterranea''. The Placozoa is a basal group of multicellular animals (metazoa). ''Trichoplax'' are very flat organisms around a millimetre in diameter, lacking any organs or internal structures. They have two cellular layers: the top epitheloid layer is made of ciliated «cover cells» flattened toward the outside of the organism, and the bottom layer is made up of cylinder cells that possess cilia used in locomotion, and gland cells that lack cilia. Between these layers is the fibre syncytium, a liquid-filled cavity strutted open by star-like fibres. ''Trichoplax'' feed by absorbing food particles—mainly microbes—with their underside. They generally reproduce asexually, by dividing or budding, but can also reproduce sexually. Though ''Trichoplax'' has a small genome in comparison to other animals, nearly 87% of its 11,514 pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trichoplacidae
''Trichoplax adhaerens'' is one of the three named species in the phylum Placozoa. The others are '' Hoilungia hongkongensis'' and '' Polyplacotoma mediterranea''. The Placozoa is a basal group of multicellular animals (metazoa). ''Trichoplax'' are very flat organisms around a millimetre in diameter, lacking any organs or internal structures. They have two cellular layers: the top epitheloid layer is made of ciliated «cover cells» flattened toward the outside of the organism, and the bottom layer is made up of cylinder cells that possess cilia used in locomotion, and gland cells that lack cilia. Between these layers is the fibre syncytium, a liquid-filled cavity strutted open by star-like fibres. ''Trichoplax'' feed by absorbing food particles—mainly microbes—with their underside. They generally reproduce asexually, by dividing or budding, but can also reproduce sexually. Though ''Trichoplax'' has a small genome in comparison to other animals, nearly 87% of its 11,514 pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dickinsonia
''Dickinsonia'' is an extinct genus of basal animal that lived during the late Ediacaran period in what is now Australia, China, Russia and Ukraine. The individual ''Dickinsonia'' typically resembles a bilaterally symmetrical ribbed oval. Its affinities are presently unknown; its mode of growth is consistent with a stem-group bilaterian affinity, though some have suggested that it belongs to the fungi, or even an "extinct kingdom". It lived during the late Ediacaran (part of Precambrian). The discovery of cholesterol molecules in fossils of ''Dickinsonia'' lends support to the idea that ''Dickinsonia'' was an animal. Description ''Dickinsonia'' fossils are known only in the form of imprints and casts in sandstone beds. The specimens found range from a few millimetres to about in length, and from a fraction of a millimetre to a few millimetres thick. They are nearly bilaterally symmetric, segmented, round or oval in outline, slightly expanded to one end (i.e. egg-shaped out ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hoilungia Hongkongensis
''Hoilungia hongkongensis'' is a species in the phylum Placozoa. The organism appears superficially similar to ''Trichoplax adhaerens'', but genetic analysis of its mitochondrial DNA shows numerous differences. It was discovered in brackish water from mangrove swamps in Hong Kong. These organisms are generally found in the biofilm surfaces in tropical and subtropical environments. Phylogenetically, they are placed closest to cnidarians. They are diploblastic animals and are believed to have dorso-ventral polarity along top and bottom body layers. Their body is overtly similar to oral-aboral axis of cnidarians. They feed from lower tissue layer which has various peptidergic gland cells. They feed on algae, bacteria, yeast and other byproducts of biofilms. They reproduce asexually through binary fission and there is also some evidence of sexual reproduction. The ''Hoilungia hongkongensis'' genome adds support to the phylogenetic placement of the Placozoa in the animal tree of life ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyplacotoma Mediterranea
''Polyplacotoma mediterranea'' is a species in the phylum In biology, a phylum (; plural: phyla) is a level of classification or taxonomic rank below kingdom and above class. Traditionally, in botany the term division has been used instead of phylum, although the International Code of Nomenclature f ... Placozoa, only representative of the genus ''Polyplacotoma''. They differ greatly from other species of placozoans with regards to their morphology and genetic makeup. ''P. mediterranea'' has the smallest mitogenome, the lowest GC content, and the smallest intergenic spacer regions of all placozoans. Their bodily structure consists of elongated polytomous body branches, as well as a maximum size that is greater than 10 mm in length. The mitochondrial genome of ''Polyplacotoma mediterranea'' is also very compact and contains overlapping protein and tRNA gene codes.Miyazawa, H., Osigus, H., Rolfes, S., Kamm, K., Schierwater, B., & Nakano, H. (2020). Mitochondrial Genome Evol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Franz Eilhard Schulze
Franz Eilhard Schulze (22 March 1840 – 2 November 1921) was a German anatomist and zoologist born in Eldena, near Greifswald. Biography He studied at the Universities of Bonn and Rostock. In 1863, he received his doctorate from Rostock, where he subsequently became a lecturer of anatomy (1864) and an associate professor of comparative anatomy (1865). In 1871 he established the zoological institute at the University of Rostock.See entry oFranz Eilhard Schulzein Catalogus Professorum Rostochiensium Later on, he served as a professor at the Universities of Graz and Berlin. In 1872, he took part in the "Pomerania" expedition to the North Sea. For several years during the 1890s, he was president of the German Zoological Society (''Deutsche Zoologische Gesellschaft''). He made contributions in his studies on the anatomy and developmental history of invertebrates, in particular, his research and publications in regards to sea-sponges. He was especially interested in a class of s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endosymbiont
An ''endosymbiont'' or ''endobiont'' is any organism that lives within the body or cells of another organism most often, though not always, in a mutualistic relationship. (The term endosymbiosis is from the Greek: ἔνδον ''endon'' "within", σύν ''syn'' "together" and βίωσις ''biosis'' "living".) Examples are nitrogen-fixing bacteria (called rhizobia), which live in the root nodules of legumes, single-cell algae inside reef-building corals and bacterial endosymbionts that provide essential nutrients to insects. There are two types of symbiont transmissions. In horizontal transmission, each new generation acquires free living symbionts from the environment. An example is the nitrogen-fixing bacteria in certain plant roots. Vertical transmission takes place when the symbiont is transferred directly from parent to offspring. It is also possible for both to be involved in a mixed-mode transmission, where symbionts are transferred vertically for some generation bef ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Channel
Sodium channels are integral membrane proteins that form ion channels, conducting sodium ions (Na+) through a cell's membrane. They belong to the superfamily of cation channels and can be classified according to the trigger that opens the channel for such ions, i.e. either a voltage-change ("voltage-gated", "voltage-sensitive", or "voltage-dependent" sodium channel; also called "VGSCs" or "Nav channel") or a binding of a substance (a ligand) to the channel ( ligand-gated sodium channels). In excitable cells such as neurons, myocytes, and certain types of glia, sodium channels are responsible for the rising phase of action potentials. These channels go through three different states called resting, active and inactive states. Even though the resting and inactive states would not allow the ions to flow through the channels the difference exists with respect to their structural conformation. Selectivity Sodium channels are highly selective for the transport of ions across cell memb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
