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Paramecium Bursaria
''Paramecium bursaria'' is a species of ciliate found in marine and brackish waters. It has a mutualistic endosymbiotic relationship with green algae called ''Zoochlorella''. The algae live inside the ''Paramecium'' in its cytoplasm and provide it with food, while the ''Paramecium'' provides the algae with movement and protection. ''P. bursaria'' is 80-150 μm long, with a wide oral groove, two contractile vacuoles, and a single micronucleus as well as a single macronucleus. ''P. bursaria'' is the only species of ''Paramecium'' that forms symbiotic relationships with algae, and it is often used in biology classrooms both as an example of a protozoan and also as an example of symbiosis. A transcriptome sequence is determined. File:Paramecium bursaria.jpg, ''Paramecium bursaria'' with green zoochlorellae living inside endosymbiotic An ''endosymbiont'' or ''endobiont'' is any organism that lives within the body or cells of another organism most often, though not always, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jakob Friedrich Ehrhart
Jakob Friedrich Ehrhart (4 November 1742, Holderbank, Aargau – 26 June 1795) was a German botanist, a pupil of Carl Linnaeus at Uppsala University, and later director of the Botanical Garden of Hannover, where he produced several major botanical works between 1780 and 1793. Ehrhart was the first author to use the rank of subspecies in botanical literature, and he published many subspecific names between 1780 and 1789. In 1779, Carl Peter Thunberg (1743–1828) named a genus of grasses, ''Ehrharta'', in Ehrhart's honor. Publications * ''Chloris hanoverana'', 1776. * ''Supplementum systematis vegetabilium, generum et specierum plantarum'', 1781. * ''Beiträge zur Naturkunde, und den damit verwandten Wissenschaften, besonders der Botanik, Chemie, Haus- und Landwirthschaft, Arzneigelahrtheit und Apothekerkunst'', seven volumes (1787 to 1792) – Contributions to natural history, etc. * Autobiography in Usteri's Annals of Botany.List of publications copied from an article on Jakob ... [...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] |
Endosymbiotic
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] |
Algae
Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular microalgae, such as ''Chlorella,'' ''Prototheca'' and the diatoms, to multicellular forms, such as the giant kelp, a large brown alga which may grow up to in length. Most are aquatic and autotrophic (they generate food internally) and lack many of the distinct cell and tissue types, such as stomata, xylem and phloem that are found in land plants. The largest and most complex marine algae are called seaweeds, while the most complex freshwater forms are the ''Charophyta'', a division of green algae which includes, for example, ''Spirogyra'' and stoneworts. No definition of algae is generally accepted. One definition is that algae "have chlorophyll ''a'' as their primary photosynthetic pigment and lack a sterile covering of cells around thei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zoochlorella
''Zoochlorella'' is a ''nomen rejiciendum'' for a genus of green algae assigned to ''Chlorella''. The term zoochlorella (plural zoochlorellae) is sometimes used to refer to any green algae that lives symbiotically within the body of a freshwater or marine invertebrate or protozoan. Zoochlorellae and zooxanthellae may both be found in the Pacific coast sea anemones ''Anthopleura elegantissima'' and ''Anthopleura xanthogrammica''. The analogy between ''Zoochlorella'' and chloroplasts has been used by the botanist Konstantin Mereschkowski in 1905 to argue about the symbiotic origin of chloroplasts (then called 'chromatophores', a term used for completely different structures today).Martin W, and Kowallik, K V. 1999, Annotated English translation of Mereschkowsky's 1905 paper 'Über Nature und Ursprung der Chromatophoren im Pflanzenreich'. Eur. J. Phycol., 34: 287-295Free access to the article Zoochlorellae are responsible for the greenish colour of sea anemone tentacle In zoolo ... [...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] |
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 proces ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oral Groove
The word oral may refer to: Relating to the mouth * Relating to the mouth, the first portion of the alimentary canal that primarily receives food and liquid **Oral administration of medicines ** Oral examination (also known as an oral exam or oral test), a practice in many schools and disciplines in which an examiner poses questions to the student in spoken form ** Oral hygiene, practices involved in cleaning the mouth and preventing disease **Oral medication **Oral rehydration therapy, a simple treatment for dehydration associated with diarrhea **Oral sex, sexual activity involving the stimulation of genitalia by use of the mouth, tongue, teeth or throat. **Oral stage, a human development phase in Freudian developmental psychology **Oral tradition, cultural material and tradition transmitted orally from one generation to another **Oralism, the education of deaf students through oral language by using lip reading, and mimicking of mouth shapes and breathing patterns **Speech commu ... [...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] |
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 instability. Micronuclei are commonly seen in cancerous cells and may indicate genomic damage events that can increase the risk of developmental or degenerative diseases. Micronuclei form during anaphase from lagging acentric chromosome or chromatid fragments caused by incorrectly repaired or unrepaired DNA breaks or by nondisjunction of chromosomes. This incorrect segregation of chromosomes may result from hypomethylation of repeat sequences present in pericentromeric DNA, irregularities in kinetochore proteins or their assembly, dysfunctional spindle apparatus, or flawed anaphase checkpoint genes. Micronuclei can contribute to genome instability by promoting a catastrophic mutational event called chromothripsis. Many micronucleus assays ha ... [...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] |
Zoochlorellae
''Zoochlorella'' is a ''nomen rejiciendum'' for a genus of green algae assigned to ''Chlorella''. The term zoochlorella (plural zoochlorellae) is sometimes used to refer to any green algae that lives symbiotically within the body of a freshwater or marine invertebrate or protozoan. Zoochlorellae and zooxanthellae may both be found in the Pacific coast sea anemones ''Anthopleura elegantissima'' and ''Anthopleura xanthogrammica''. The analogy between ''Zoochlorella'' and chloroplasts has been used by the botanist Konstantin Mereschkowski in 1905 to argue about the symbiotic origin of chloroplasts (then called 'chromatophores', a term used for completely different structures today).Martin W, and Kowallik, K V. 1999, Annotated English translation of Mereschkowsky's 1905 paper 'Über Nature und Ursprung der Chromatophoren im Pflanzenreich'. Eur. J. Phycol., 34: 287-295Free access to the article Zoochlorellae are responsible for the greenish colour of sea anemone tentacle In zoolo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
