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Climacostomum
''Climacostomum'' is a genus of unicellular ciliates, belonging to the class Heterotrichea. The genus has one well-described species, ''Climacostomum virens'', which usually carries a symbiotic alga, a variety of ''Chlorella'' that can be cultivated outside its host. Algae-free (aposymbiotic) individuals are known, and a species that lacks algal symbionts, ''Climacostomum gigas'' Meunier 1907, has been identified, but not confirmed in recent literature. In its cortex, ''Climacostomum virens'' has colorless granules structurally similar to the defensive pigmentocysts found in its fellow Heterotrichs, ''Stentor coreuleus'' and ''Blepharisma japonicum''. When ''Climacostomum'' is threatened by a predator, such as the ciliate ''Dileptus margaritifer,'' these cortical cysts release a defensive cytotoxin called Climacostol. This substance has been synthesized in the laboratory and found to be highly toxic to certain species of ciliates. It is believed that this toxicity is accomplishe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Climacostomum Sp
''Climacostomum'' is a genus of unicellular ciliates, belonging to the class Heterotrichea. The genus has one well-described species, ''Climacostomum virens'', which usually carries a symbiotic alga, a variety of ''Chlorella'' that can be cultivated outside its host. Algae-free ( aposymbiotic) individuals are known, and a species that lacks algal symbionts, ''Climacostomum gigas'' Meunier 1907, has been identified, but not confirmed in recent literature. In its cortex, ''Climacostomum virens'' has colorless granules structurally similar to the defensive pigmentocysts found in its fellow Heterotrichs, ''Stentor coreuleus'' and ''Blepharisma japonicum''. When ''Climacostomum'' is threatened by a predator, such as the ciliate ''Dileptus margaritifer,'' these cortical cysts release a defensive cytotoxin called Climacostol. This substance has been synthesized in the laboratory and found to be highly toxic to certain species of ciliates. It is believed that this toxicity is accomplis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Climacostomum Virens
''Climacostomum virens'' is a species of unicellular ciliate protists. It is one of just two formally described species in the genus Climacostomum. Description ''Climacostomum virens'' has a flexible but non-contractile body, long, roughly ovoid or harp-shaped, and flattened from back to front. It has a large posterior contractile vacuole, and a characteristic posterior indentation, or dimple, that is more pronounced in underfed individuals. The posterior vacuole surrounds the cytoproct (anus), through which food waste is eliminated. The macronucleus of ''Climacostomum virens'' is normally long and wormlike (vermiform). The cell's most prominent feature is its large oral apparatus, which occupies most of the anterior region. This structure features an adoral zone of membranelles (AZM) partly encircling a wide buccal cavity (mouth), which opens into the cytopharyngeal pouch where digestive vacuoles are formed before they travel down a distinctive long, bent tube into the body of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eukaryota
The eukaryotes ( ) constitute the Domain (biology), domain of Eukaryota or Eukarya, organisms whose Cell (biology), cells have a membrane-bound cell nucleus, nucleus. All animals, plants, Fungus, fungi, seaweeds, and many unicellular organisms are eukaryotes. They constitute a major group of Outline of life forms, life forms alongside the two groups of prokaryotes: the Bacteria and the Archaea. Eukaryotes represent a small minority of the number of organisms, but given their generally much larger size, their collective global biomass is much larger than that of prokaryotes. The eukaryotes emerged within the archaeal Kingdom (biology), kingdom Asgard (Archaea), Promethearchaeati and its sole phylum Promethearchaeota. This implies that there are only Two-domain system, two domains of life, Bacteria and Archaea, with eukaryotes incorporated among the Archaea. Eukaryotes first emerged during the Paleoproterozoic, likely as Flagellated cell, flagellated cells. The leading evolutiona ... [...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, including 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, lower 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 sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Condylostoma
''Condylostoma'' is a genus of unicellular ciliate protists, belonging to the class Heterotrichea. ''Condylostoma'' is a genus of heterotrichous made up of large ciliated cells. The genus was discovered by Jean Baptiste Bory de Saint-Vincent in 1826, and over 20 species have been described since then. They are mostly marine, but some are found in freshwater lakes, and they have habitats around the globe. Morphologically they are large cells with a buccal groove that is about one third of their total length, and they are covered in cilia which grow out of their longitudinal rows of kineties. They have an adoral zone of membranelles (AZM) around the buccal groove to help capture food, but no cilia are present in the groove itself. Another feature of note is their altered genetic code. ''Condylostoma'' includes mostly benthic organisms that spend most of their time gliding along substrate looking for food. They can eat many smaller organisms between 5 μm and 40 μm in size and are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paraphyletic
Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In contrast, a monophyletic grouping (a clade) includes a common ancestor and ''all'' of its descendants. The terms are commonly used in phylogenetics (a subfield of biology) and in the tree model of historical linguistics. Paraphyletic groups are identified by a combination of synapomorphies and symplesiomorphies. If many subgroups are missing from the named group, it is said to be polyparaphyletic. The term received currency during the debates of the 1960s and 1970s accompanying the rise of cladistics, having been coined by zoologist Willi Hennig to apply to well-known taxa like Reptilia (reptiles), which is paraphyletic with respect to birds. Reptilia contains the last common ancestor of reptiles and all descendants of that ancestor exc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monophyletic
In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent common ancestor (or more precisely an ancestral population), i.e. excludes non-descendants of that common ancestor # the grouping contains all the descendants of that common ancestor, without exception Monophyly is contrasted with paraphyly and polyphyly as shown in the second diagram. A ''paraphyletic'' grouping meets 1. but not 2., thus consisting of the descendants of a common ancestor, excepting one or more monophyletic subgroups. A '' polyphyletic'' grouping meets neither criterion, and instead serves to characterize convergent relationships of biological features rather than genetic relationships – for example, night-active primates, fruit trees, or aquatic insects. As such, these characteristic features of a polyphyletic grouping ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
William Saville-Kent
William Saville-Kent (10 July 1845 – 11 October 1908) was an English marine biologist, naturalist, Commissioner and Inspector of Tasmanian Fisheries and author. He is perhaps best-known for his work in the development of the artificial pearl industry. Early life Born in the town of Sidmouth in Devon, South West England on 10 July 1845, William Saville-Kent was the son of Samuel Saville Kent (7 July 1800 – 5 February 1872) and Mary Ann Windus (b. 1808 – May 1852), who was Samuel's first wife. William was the youngest of ten children from his father's first marriage. Samuel was employed as a "Factory Commissioner" for the Home Office, and inspected factories to ensure that they were properly implementing the worker safety measures regulated in the Factory Acts of 1833. As the acts sought to alleviate the harm done to children that were caused by unregulated working conditions in the factories, Samuel's “duties required him to inspect factories that employed women and ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Christian Gottfried Ehrenberg
Christian Gottfried Ehrenberg (19 April 1795 – 27 June 1876) was a German Natural history, naturalist, zoologist, Botany, botanist, comparative anatomist, geologist, and microscopy, microscopist. He is considered to be one of the most famous and productive scientists of his time. Early collections The son of a judge, Christian Gottfried Ehrenberg was born in Delitzsch, near Leipzig. He first studied theology at the University of Leipzig, then medicine and natural sciences in Humboldt University of Berlin, Berlin and became a friend of the famous List of explorers, explorer Alexander von Humboldt. In 1818, he completed his doctoral dissertation on fungi, ''Sylvae mycologicae Berolinenses.'' In 1820–1825, on a scientific expedition to the Middle East with his friend Wilhelm Hemprich, he collected thousands of specimens of plants and animals. He investigated parts of Egypt, the Libyan Desert, the Nile, Nile valley and the northern coasts of the Red Sea, where he made a special ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
