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Didinium
''Didinium'' is a genus of unicellular ciliates with at least ten accepted species. All are free-living carnivores. Most are found in fresh and brackish water, but three marine species are known. Their diet consists largely of ''Paramecium'', although they will also attack and consume other ciliates. Some species, such as ''D. gargantua'', also feed on non-ciliate protists, including dinoflagellates, cryptomonads, and green algae. Appearance and reproduction ''Didinia'' are rounded, oval or barrel-shaped and range in length from 50 to 150 micrometres. The cell body is encircled by two ciliary bands, or ''pectinelles'', an upper band and a lower band just below the midline. This distinguishes them from the related genus '' Monodinium'', which have only a single band, except during cell division. The pectinelles are used to move ''Didinium'' through water by rotating the cell around its axis. At the anterior end, a cone-shaped structure protrudes, supported by a palisade of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Didinium Nasutum 3D-model
''Didinium'' is a genus of unicellular ciliates with at least ten accepted species. All are free-living carnivores. Most are found in fresh and brackish water, but three marine species are known. Their diet consists largely of ''Paramecium'', although they will also attack and consume other ciliates. Some species, such as ''D. gargantua'', also feed on non-ciliate protists, including dinoflagellates, cryptomonads, and green algae. Appearance and reproduction ''Didinia'' are rounded, oval or barrel-shaped and range in length from 50 to 150 micrometres. The cell body is encircled by two ciliary bands, or ''pectinelles'', an upper band and a lower band just below the midline. This distinguishes them from the related genus '' Monodinium'', which have only a single band, except during cell division. The pectinelles are used to move ''Didinium'' through water by rotating the cell around its axis. At the anterior end, a cone-shaped structure protrudes, supported by a palisade ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Didinium Nasutum Consuming A Paramecium
''Didinium'' is a genus of unicellular ciliates with at least ten accepted species. All are free-living carnivores. Most are found in fresh and brackish water, but three marine species are known. Their diet consists largely of ''Paramecium'', although they will also attack and consume other ciliates. Some species, such as ''D. gargantua'', also feed on non-ciliate protists, including dinoflagellates, cryptomonads, and green algae. Appearance and reproduction ''Didinia'' are rounded, oval or barrel-shaped and range in length from 50 to 150 micrometres. The cell body is encircled by two ciliary bands, or ''pectinelles'', an upper band and a lower band just below the midline. This distinguishes them from the related genus '' Monodinium'', which have only a single band, except during cell division. The pectinelles are used to move ''Didinium'' through water by rotating the cell around its axis. At the anterior end, a cone-shaped structure protrudes, supported by a palisade ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paramecium
'' ''Paramecium'' ( , ; also spelled ''Paramoecium'') is a genus of eukaryotic, unicellular ciliates, commonly studied as a representative of the ciliate group. ''Paramecia'' are widespread in freshwater, brackish, and marine environments and are often very abundant in stagnant basins and ponds. Because some species are readily cultivated and easily induced to conjugate and divide, it has been widely used in classrooms and laboratories to study biological processes. Its usefulness as a model organism has caused one ciliate researcher to characterize it as the " white rat" of the phylum Ciliophora. Historical background ''Paramecia'' were among the first ciliates to be seen by microscopists, in the late 17th century. They were probably known to the Dutch pioneer of protozoology, Antonie van Leeuwenhoek, and were clearly described by his contemporary Christiaan Huygens in a letter of 1678. The earliest known illustration of a Paramecium was published anonymously in Philosophi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ciliate
The ciliates are a group of alveolates characterized by the presence of hair-like organelles called cilia, which are identical in structure to flagellum, eukaryotic flagella, but are in general shorter and present in much larger numbers, with a different wikt:undulating, undulating pattern than flagella. Cilia occur in all members of the group (although the peculiar Suctoria only have them for part of their biological life cycle, life cycle) and are variously used in swimming, crawling, attachment, feeding, and sensation. Ciliates are an important group of protists, common almost anywhere there is water—in lakes, ponds, oceans, rivers, and soils. About 4,500 unique free-living species have been described, and the potential number of extant species is estimated at 27,000–40,000. Included in this number are many Ectosymbiosis, ectosymbiotic and endosymbiotic species, as well as some Obligate parasite, obligate and Facultative parasite, opportunistic parasites. Ciliate species r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Litostomatea
The Litostomatea are a class of ciliates. The group consists of three subclasses: Haptoria, Trichostomatia and Rhynchostomatia. Haptoria includes mostly carnivorous forms such as ''Didinium'', a species of which preys primarily on the ciliate ''Paramecium''. Trichostomatia (trichostomes) are mostly endosymbionts in the digestive tracts of vertebrates. These include the species ''Balantidium coli'', which is the only ciliate parasitic in humans. The group Rhynchostomatia includes two free-living orders previously included among the Haptoria, but now known to be genetically distinct from them, the Dileptida and the Tracheliida. Morphology In litostomes, the body cilia arise from structures in the cell cortex called monokinetids, which are made up of a single cilium and its associated structures, such as basal bodies and microtubular fibres. These have an ultrastructural arrangement characteristic to the group. The cell "mouth" (cytostome) is apical or subapical. In trichostomes it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vladimir Timofeyevich Szewiakow
Vladimir Timofeyevich Shevyakov, in Russian Владимир Тимофеевич Шевяков (29 October 1859, St. Petersburg – 18 October 1930, Irkutsk) was a Russian biologist who worked on Protozoa. Shevyakov studied under Konstantin Mereschkowski in St. Petersburg and Otto Bütschli at the University of Heidelberg. He was married to Lydia Kowalevsky, the youngest daughter of Alexander Kovalevsky. He was a professor at St. Petersburg University until 1911 when he left science and became a vice-minister in the government of Tzar Nicholas. During the revolution he and his family moved first to Perm in Ural and in 1920 he became professor in Irkutsk. He is mainly known for his work on Radiolaria, Ciliata and Acantharea. He described many taxa. Most of his publications are under the German spelling of his name which is Schewiakoff. Works Über die karyokinetische Kerntheilung der ''Euglypha alveolata'' "Morphologische Jahrbuch" 13, ss. 193–258 (1888) * Man w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Contractile Vacuole
A contractile vacuole (CV) is a sub-cellular structure (organelle) involved in osmoregulation. It is found predominantly in protists and in unicellular algae. It was previously known as pulsatile or pulsating vacuole. Overview The contractile vacuole is a specialized type of vacuole that regulates the quantity of water inside a cell. In freshwater environments, the concentration of solutes is hypotonic, lesser outside than inside the cell. Under these conditions, osmosis causes water to accumulate in the cell from the external environment. The contractile vacuole acts as part of a protective mechanism that prevents the cell from absorbing too much water and possibly lysing (rupturing) through excessive internal pressure. The contractile vacuole, as its name suggests, expels water out of the cell by contracting. The growth (water gathering) and contraction (water expulsion) of the contractile vacuole are periodical. One cycle takes several seconds, depending on the species and t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytostome
A cytostome (from ''cyto-'', cell and ''stome-'', mouth) or cell mouth is a part of a cell specialized for phagocytosis, usually in the form of a microtubule-supported funnel or groove. Food is directed into the cytostome, and sealed into vacuoles. Only certain groups of protozoa, such as the Ciliophora and Excavata, have cytostomes. An example is '' Balantidium coli'', a ciliate. In other protozoa, and in cells from multicellular organisms, phagocytosis takes place at any point on the cell or feeding takes place by absorption. Structure The cytostome forms an invagination on the cell surface and is typically directed towards the nucleus of the cell.Okuda, Kendi, et al. "The cytostome of Trypanosoma cruzi epimastigotes is associated with the flagellar complex." Experimental parasitology 92.4 (1999): 223-231. The cytostome is often labeled as the entire invagination, but in fact the cytostome only constitutes the opening of the invagination at the surface of the cell. The rest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macronucleus
A macronucleus (formerly also meganucleus) is the larger type of nucleus in ciliates. Macronuclei are polyploid and undergo direct division without mitosis. It controls the non-reproductive cell functions, such as metabolism. During conjugation, the macronucleus disintegrates, and a new macronucleus is formed by karyogamy of the micronuclei. The macronucleus contains hundreds to thousands of chromosomes, each present in many copies. The macronucleus lacks a mechanism to precisely partition this complex genome equally during nuclear division; thus, how the cell manages to maintain a balanced genome after generations of divisions is unknown. See also *Micronucleus Micronucleus is the name given to the small nucleus that forms whenever a chromosome or a fragment of a chromosome is not incorporated into one of the daughter nuclei during cell division. It usually is a sign of genotoxic events and chromosomal i ... References . Cell nucleus Ciliate biology {{Ciliat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asexual Reproduction
Asexual reproduction is a type of reproduction that does not involve the fusion of gametes or change in the number of chromosomes. The offspring that arise by asexual reproduction from either unicellular or multicellular organisms inherit the full set of genes of their single parent and thus the newly created individual is genetically and physically similar to the parent or an exact clone of the parent. Asexual reproduction is the primary form of reproduction for single-celled organisms such as archaea and eubacteria, bacteria. Many Eukaryote, eukaryotic organisms including plants, animals, and Fungus, fungi can also reproduce asexually. In vertebrates, the most common form of asexual reproduction is parthenogenesis, which is typically used as an alternative to sexual reproduction in times when reproductive opportunities are limited. Komodo dragons and some monitor lizards can also reproduce asexually. While all prokaryotes reproduce without the formation and fusion of gametes, m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anal Pore
The anal pore or cytoproct is a structure in various single-celled eukaryotes where waste is ejected after the nutrients from food have been absorbed into the cytoplasm. In ciliates, the anal pore (cytopyge) and cytostome are the only regions of the pellicle that are not covered by ridges, cilia or rigid covering. They serve as analogues of, respectively, the anus and mouth In animal anatomy, the mouth, also known as the oral cavity, or in Latin cavum oris, is the opening through which many animals take in food and issue vocal sounds. It is also the cavity lying at the upper end of the alimentary canal, bounded on ... of multicellular organisms. The cytopyge's thin membrane allows vacuoles to be merged into the cell wall and emptied. Location The anal pore is an exterior opening of microscopic organisms through which undigested food waste, water, or gas are expelled from the body. It is also referred to as a cytoproct. This structure is found in different unicellular ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biological Reproduction
Reproduction (or procreation or breeding) is the biological process by which new individual organisms – "offspring" – are produced from their "parent" or parents. Reproduction is a fundamental feature of all known life; each individual organism exists as the result of reproduction. There are two forms of reproduction: asexual and sexual. In asexual reproduction, an organism can reproduce without the involvement of another organism. Asexual reproduction is not limited to single-celled organisms. The cloning of an organism is a form of asexual reproduction. By asexual reproduction, an organism creates a genetically similar or identical copy of itself. The evolution of sexual reproduction is a major puzzle for biologists. The two-fold cost of sexual reproduction is that only 50% of organisms reproduce and organisms only pass on 50% of their genes.John Maynard Smith ''The Evolution of Sex'' 1978. Sexual reproduction typically requires the sexual interaction of two specialize ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
