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Dracoamoeba
''Dracoamoeba'' is a free-living genus of discosean amoebae in the family Acanthamoebidae containing the sole species ''Dracoamoeba jomungandri'', discovered in 2016 in moist muddy soil close to the ocean shore at Chincoteague, Virginia ( USA). Etymology The generic name ''Dracoamoeba'' comes from the latin “Draco”, meaning “ dragon”, which is what the forms of this amoeba resemble. The specific epithet ''jomungandri'' comes from Jörmungandr, the oceanic sea serpent of norse mythology. Morphology Members of ''Dracoamoeba'' are amoebae with ramose pseudopodia capable of forming one lamellipodium with acanthapodial (i.e. tooth-shaped) subpseudopodia. Pseudopodia of all forms are made up of hyaloplasm, a hyaline cytoplasm that composes the pseudopodia, and are used for locomotion and feeding. Their cell body is made of granuloplasm, a granulose cytoplasm that surrounds the nucleus as opposed to the hyaloplasm. In particular, ''D. jomungandri'' exhibits long, taperin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acanthamoebidae
Acanthamoebidae is a family of single-celled eukaryotes within the group Amoebozoa. It gets its name from ''Acanthamoeba'', its best-known member. However, it also includes other species, such as ''Comandonia operculata'' and '' Protacanthamoeba bohemica''. Many kinds of Acanthamoebidae are highly prevalent in the soil and water of a variety of environments. They are similar to Hartmannella, but have differently structured pseudopodia, in regard to the actin microfilaments that comprise them. Its most prominent member, ''Acanthamoeba'', can be potentially pathogenic to humans and animals. It has been described as having a common origin with the Entamoebidae and Dictyosteliida. Structure Members of Acanthamoebidae have a specific form of pseudopodia, dubbed acanthopodia. These acanthopodia are continuously formed and reabsorbed, protrude from every area of the cell’s surface, and are usually, short and fine. An exception would be ''A. astronyxis'' and ''A. comandoni'', in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Discosea
Discosea is a class of Amoebozoa, consisting of naked amoebae with a flattened, discoid body shape. Members of the group do not produce tubular or subcylindrical pseudopodia, like amoebae of the class Tubulinea. When a discosean is in motion, a transparent layer called ''hyaloplasm'' forms at the leading edge of the cell (see lamelliopodium). In some discoseans, short "subpseudopodia" may be extended from this hyaloplasm, but the granular contents of the cell do not flow into these, as in true pseudopodia. Discosean amoebae lack hard shells, but some, like '' Cochliopodium'' and '' Korotnevella'' secrete intricate organic scales which may cover the upper (dorsal) surface of the cell. No species have flagella or flagellated stages of life. The composition of Discosea is similar to that of the class Flabellinea, proposed by Alexey Smirnov and his collaborators in 2005. However, Discosea is a more comprehensive taxon, including several groups not included in Flabellinea. In 2011 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micrometre
The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer ( American spelling), also commonly known as a micron, is a unit of length in the International System of Units (SI) equalling (SI standard prefix " micro-" = ); that is, one millionth of a metre (or one thousandth of a millimetre, , or about ). The nearest smaller common SI unit is the nanometre, equivalent to one thousandth of a micrometre, one millionth of a millimetre or one billionth of a metre (). The micrometre is a common unit of measurement for wavelengths of infrared radiation as well as sizes of biological cells and bacteria, and for grading wool by the diameter of the fibres. The width of a single human hair ranges from approximately 20 to . The longest human chromosome, chromosome 1, is approximately in length. Examples Between 1 μm and 10 μm: * 1–10 μm – length of a typical bacterium * 3–8 μm � ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleus (cell)
The cell nucleus (pl. nuclei; from Latin or , meaning ''kernel'' or ''seed'') is a membrane-bound organelle found in eukaryotic cells. Eukaryotic cells usually have a single nucleus, but a few cell types, such as mammalian red blood cells, have no nuclei, and a few others including osteoclasts have many. The main structures making up the nucleus are the nuclear envelope, a double membrane that encloses the entire organelle and isolates its contents from the cellular cytoplasm; and the nuclear matrix, a network within the nucleus that adds mechanical support. The cell nucleus contains nearly all of the cell's genome. Nuclear DNA is often organized into multiple chromosomes – long stands of DNA dotted with various proteins, such as histones, that protect and organize the DNA. The genes within these chromosomes are structured in such a way to promote cell function. The nucleus maintains the integrity of genes and controls the activities of the cell by regulating gene expre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytoplasm
In cell biology, the cytoplasm is all of the material within a eukaryotic cell, enclosed by the cell membrane, except for the cell nucleus. The material inside the nucleus and contained within the nuclear membrane is termed the nucleoplasm. The main components of the cytoplasm are cytosol (a gel-like substance), the organelles (the cell's internal sub-structures), and various cytoplasmic inclusions. The cytoplasm is about 80% water and is usually colorless. The submicroscopic ground cell substance or cytoplasmic matrix which remains after exclusion of the cell organelles and particles is groundplasm. It is the hyaloplasm of light microscopy, a highly complex, polyphasic system in which all resolvable cytoplasmic elements are suspended, including the larger organelles such as the ribosomes, mitochondria, the plant plastids, lipid droplets, and vacuoles. Most cellular activities take place within the cytoplasm, such as many metabolic pathways including glycolysis, and proc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyaline
A hyaline substance is one with a glassy appearance. The word is derived from el, ὑάλινος, translit=hyálinos, lit=transparent, and el, ὕαλος, translit=hýalos, lit=crystal, glass, label=none. Histopathology Hyaline cartilage is named after its glassy appearance on fresh gross pathology. On light microscopy of H&E stained slides, the extracellular matrix of hyaline cartilage looks homogeneously pink, and the term "hyaline" is used to describe similarly homogeneously pink material besides the cartilage. Hyaline material is usually acellular and proteinaceous. For example, arterial hyaline is seen in aging, high blood pressure, diabetes mellitus Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level (hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ... and in association with some drugs (e.g. calcineurin inhibitors) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudopodia
A pseudopod or pseudopodium (plural: pseudopods or pseudopodia) is a temporary arm-like projection of a eukaryotic cell membrane that is emerged in the direction of movement. Filled with cytoplasm, pseudopodia primarily consist of actin filaments and may also contain microtubules and intermediate filaments. Pseudopods are used for motility and ingestion. They are often found in amoebas. Different types of pseudopodia can be classified by their distinct appearances. Lamellipodia are broad and thin. Filopodia are slender, thread-like, and are supported largely by microfilaments. Lobopodia are bulbous and amoebic. Reticulopodia are complex structures bearing individual pseudopodia which form irregular nets. Axopodia are the phagocytosis type with long, thin pseudopods supported by complex microtubule arrays enveloped with cytoplasm; they respond rapidly to physical contact. Some pseudopodial cells are able to use multiple types of pseudopodia depending on the situation: Most of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lamellipodium
The lamellipodium (plural lamellipodia) (from Latin ''lamella'', related to ', "thin sheet", and the Greek radical ''pod-'', "foot") is a cytoskeletal protein actin projection on the leading edge of the cell. It contains a quasi-two-dimensional actin mesh; the whole structure propels the cell across a substrate. Within the lamellipodia are ribs of actin called microspikes, which, when they spread beyond the lamellipodium frontier, are called filopodia. The lamellipodium is born of actin nucleation in the plasma membrane of the cell and is the primary area of actin incorporation or microfilament formation of the cell. Description Lamellipodia are found primarily in all mobile cells, such as the keratinocytes of fish and frogs, which are involved in the quick repair of wounds. The lamellipodia of these keratinocytes allow them to move at speeds of 10–20 μm / min over epithelial surfaces. When separated from the main part of a cell, a lamellipodium can still cr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudopodia
A pseudopod or pseudopodium (plural: pseudopods or pseudopodia) is a temporary arm-like projection of a eukaryotic cell membrane that is emerged in the direction of movement. Filled with cytoplasm, pseudopodia primarily consist of actin filaments and may also contain microtubules and intermediate filaments. Pseudopods are used for motility and ingestion. They are often found in amoebas. Different types of pseudopodia can be classified by their distinct appearances. Lamellipodia are broad and thin. Filopodia are slender, thread-like, and are supported largely by microfilaments. Lobopodia are bulbous and amoebic. Reticulopodia are complex structures bearing individual pseudopodia which form irregular nets. Axopodia are the phagocytosis type with long, thin pseudopods supported by complex microtubule arrays enveloped with cytoplasm; they respond rapidly to physical contact. Some pseudopodial cells are able to use multiple types of pseudopodia depending on the situation: Most of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Norse Mythology
Norse, Nordic, or Scandinavian mythology is the body of myths belonging to the North Germanic peoples, stemming from Old Norse religion and continuing after the Christianization of Scandinavia, and into the Nordic folklore of the modern period. The northernmost extension of Germanic mythology and stemming from Proto-Germanic folklore, Norse mythology consists of tales of various deities, beings, and heroes derived from numerous sources from both before and after the pagan period, including medieval manuscripts, archaeological representations, and folk tradition. The source texts mention numerous gods such as the thunder-god Thor, the raven-flanked god Odin, the goddess Freyja, and numerous other deities. Most of the surviving mythology centers on the plights of the gods and their interaction with several other beings, such as humanity and the jötnar, beings who may be friends, lovers, foes, or family members of the gods. The cosmos in Norse mythology consists of Nine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Serpent
A sea serpent or sea dragon is a type of dragon sea monster described in various mythologies, most notably Mesopotamian (Tiamat), Judaeo-Christian (Leviathan), Greek (Cetus, Echidna, Hydra, Scylla), and Norse ( Jörmungandr). Mythology and folklore Mediterranean and Western Asia The mytheme, the chief god in the role of the hero slaying a sea serpent, is widespread both in the ancient Near East and in Indo-European mythology, e.g. Lotan and Hadad, Leviathan and Yahweh, Tiamat and Marduk (see also Labbu, Bašmu, Mušḫuššu), Illuyanka and Tarhunt, Yammu and Baal in the Baal Cycle etc. The Hebrew Bible also has less mythological descriptions of large sea creatures as part of creation under God's command, such as the Tanninim mentioned in Book of Genesis 1:21 and the "great serpent" of Amos 9:3. In the Aeneid, a pair of sea serpents killed Laocoön and his sons when Laocoön argued against bringing the Trojan Horse into Troy. In antiquity and in the Bible, dragon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jörmungandr
In Norse mythology, Jörmungandr ( non, Jǫrmungandr, lit=the Vast gand, see Etymology), also known as the Midgard Serpent or World Serpent ( non, Miðgarðsormr), is an unfathomably large sea serpent or worm who dwells in the world sea, encircling the Earth (Midgard) and biting his own tail, an example of an ouroboros. As a result of it surrounding Midgard (the Earth) it is referred to as the World Serpent. When it releases its tail, Ragnarök (the final battle of the world) will begin. Jörmungandr is said to be the middle child of the trickster god Loki and the giantess Angrboða. According to the '' Prose Edda'', Odin took Loki's three children by Angrboða – the wolf Fenrir, the goddess Hel, and the serpent Jörmungandr – and removed them from Asgard (the world of the Æsir). The serpent Jörmungandr was tossed into the great ocean that encircles Midgard.Snorri Sturluson; Brodeur, Arthur Gilchrist (trans.) (1916). ''The Prose Edda''. New York: The American-Sca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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