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Gambierdiscus Toxicus
''Gambierdiscus toxicus'' is a species of photosynthetic unicellular eukaryote belonging to the Alveolata, part of the SAR supergroup. It is a dinoflagellate which can cause the foodborne illness ciguatera, and is known to produce several natural polyethers including ciguatoxin, maitotoxin, gambieric acid, and gambierol. The species was discovered attached to the surface of brown macroalgae. History This species was first described by Adachi, R. & Fukuyo, Y in 1979 using samples collected around Gambier Islands. Which was split into five different species (''Gambierdiscus caribaeus'', ''Gambierdiscus carolinianus'', ''Gambierdiscus carpenteri'', ''Gambierdiscus ruetzleri'' and ''Gambierdiscus toxicus'') according to their morphological characteristic of thecal structure, and the sequence of both D1–D3 and D8–D10 regions in large-subunit rDNA. Distribution This species can be found in tropical and subtropical regions in Pacific Ocean and Indian Ocean. It is often ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eukaryote
Eukaryotes () are organisms whose cells have a nucleus. All animals, plants, fungi, and many unicellular organisms, are Eukaryotes. They belong to the group of organisms Eukaryota or Eukarya, which is one of the three domains of life. Bacteria and Archaea (both prokaryotes) make up the other two domains. The eukaryotes are usually now regarded as having emerged in the Archaea or as a sister of the Asgard archaea. This implies that there are only two domains of life, Bacteria and Archaea, with eukaryotes incorporated among archaea. Eukaryotes represent a small minority of the number of organisms, but, due to their generally much larger size, their collective global biomass is estimated to be about equal to that of prokaryotes. Eukaryotes emerged approximately 2.3–1.8 billion years ago, during the Proterozoic eon, likely as flagellated phagotrophs. Their name comes from the Greek εὖ (''eu'', "well" or "good") and κάρυον (''karyon'', "nut" or "kernel"). Euka ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alveolate
The alveolates (meaning "pitted like a honeycomb") are a group of protists, considered a major clade and Biological classification, superphylum within Eukarya. They are currently grouped with the stramenopiles and Rhizaria among the protists with tubulocristate mitochondria, the group being referred to as SAR supergroup, SAR. Characteristics The most notable shared characteristic is the presence of cortical (near the surface) alveoli (sacs). These are flattened vesicle (biology), vesicles (sacs) arranged as a layer just under the cell membrane, membrane and supporting it, typically contributing to a flexible pellicle (thin skin). In armored dinoflagellates they may contain stiff plates. Alveolates have mitochondrion, mitochondria with tubular cristae (invaginations), and cells often have pore-like intrusions through the cell surface. The group contains free-living and parasitic organisms, predatory flagellates, and photosynthetic organisms. Almost all sequenced mitochondrial g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SAR Supergroup
The SAR supergroup, also just SAR or Harosa, is a clade that includes stramenopiles (heterokonts), alveolates, and Rhizaria. The name is an acronym derived from the first letters of each of these clades; it has been alternatively spelled "RAS". The term "Harosa" (at the subkingdom level) has also been used. The SAR supergroup is a node-based taxon. Note that as a formal taxon, "Sar" has only its first letter capitalized, while the earlier abbreviation, SAR, retains all uppercase letters. Both names refer to the same group of organisms, unless further taxonomic revisions deem otherwise. Members of the SAR supergroup were once included under the separate supergroups Chromalveolata (Chromista and Alveolata) and Rhizaria, until phylogenetic studies confirmed that stramenopiles and alveolates diverged with Rhizaria. This apparently excluded haptophytes and cryptomonads, leading Okamoto ''et al.'' (2009) to propose the clade Hacrobia to accommodate them. Phylogeny Based on a compi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dinoflagellate
The dinoflagellates (Greek δῖνος ''dinos'' "whirling" and Latin ''flagellum'' "whip, scourge") are a monophyletic group of single-celled eukaryotes constituting the phylum Dinoflagellata and are usually considered algae. Dinoflagellates are mostly marine plankton, but they also are common in freshwater habitats. Their populations vary with sea surface temperature, salinity, and depth. Many dinoflagellates are photosynthetic, but a large fraction of these are in fact mixotrophic, combining photosynthesis with ingestion of prey (phagotrophy and myzocytosis). In terms of number of species, dinoflagellates are one of the largest groups of marine eukaryotes, although substantially smaller than diatoms. Some species are endosymbionts of marine animals and play an important part in the biology of coral reefs. Other dinoflagellates are unpigmented predators on other protozoa, and a few forms are parasitic (for example, ''Oodinium'' and ''Pfiesteria''). Some dinoflagellates pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ciguatera
Ciguatera fish poisoning (CFP), also known simply as ciguatera, is a foodborne illness caused by eating reef fish whose flesh is contaminated with certain toxins. Such individual fish are said to be ciguatoxic. Symptoms may include diarrhea, vomiting, numbness, itchiness, sensitivity to hot and cold, dizziness, and weakness. The onset of symptoms varies with the amount of toxin eaten from half an hour to up to two days. The diarrhea may last for up to four days. Some symptoms typically remain for a few weeks to months. Heart difficulties such as bradycardia, slow heart rate and low blood pressure may also occur. The specific toxins involved are ciguatoxin and maitotoxin. They are originally made by a small marine organism, ''Gambierdiscus toxicus'', that grows on and around coral reefs in tropical and subtropical waters. These are eaten by herbivorous fish which in turn are eaten by larger carnivorous fish. The toxins become Bioaccumulation, more concentrated as they move up the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyether
In organic chemistry, ethers are a class of compounds that contain an ether group—an oxygen atom connected to two alkyl or aryl groups. They have the general formula , where R and R′ represent the alkyl or aryl groups. Ethers can again be classified into two varieties: if the alkyl or aryl groups are the same on both sides of the oxygen atom, then it is a simple or symmetrical ether, whereas if they are different, the ethers are called mixed or unsymmetrical ethers. A typical example of the first group is the solvent and anaesthetic diethyl ether, commonly referred to simply as "ether" (). Ethers are common in organic chemistry and even more prevalent in biochemistry, as they are common linkages in carbohydrates and lignin. Structure and bonding Ethers feature bent C–O–C linkages. In dimethyl ether, the bond angle is 111° and C–O distances are 141 pm. The barrier to rotation about the C–O bonds is low. The bonding of oxygen in ethers, alcohols, and water is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ciguatoxin
image:ciguatoxin.svg, 300px, Chemical structure of the ciguatoxin CTX1B Ciguatoxins are a class of toxic Polycyclic compound, polycyclic polyethers found in fish that cause ciguatera. There are several different chemicals in this class. "CTX" is often used as an abbreviation. * - Ciguatoxin 1 * - Ciguatoxin 2 * - Ciguatoxin 3 * - Ciguatoxin 4B (Gambiertoxin 4b) Toxic effect on humans Ciguatoxins do not harm the fish that carry them, but they are poisonous to humans. They cannot be smelled or tasted and cannot be destroyed by cooking. Rapid testing for this toxin in food is not standard. Some ciguatoxins lower the threshold for opening excitatory voltage-gated sodium channels in the nervous system. Opening a sodium channel causes depolarization, which could sequentially cause paralysis, heart contraction, and changing the senses of heat and cold. Such poisoning from ciguatoxins is known as ciguatera. Ciguatoxins are lipophillic, able to cross the blood brain barrier, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maitotoxin
Maitotoxin (or MTX) is an extremely powerful biotoxin produced by ''Gambierdiscus toxicus'', a dinoflagellate species. Maitotoxin has been shown to be more than one hundred thousand times more potent than VX nerve agent. Maitotoxin is so potent that it has been demonstrated that an intraperitoneal injection of 130 ng/kg was lethal in mice. Maitotoxin was named from the ciguateric fish ''Ctenochaetus striatus''—called "maito" in Tahiti—from which maitotoxin was isolated for the first time. It was later shown that maitotoxin is actually produced by the dinoflagellate ''Gambierdiscus toxicus''. Mechanism of toxicity Maitotoxin activates extracellular calcium channels, leading to an increase in levels of cytosolic Ca2+ ions. The exact molecular target of maitotoxin is unknown, but it has been suggested that maitotoxin binds to the plasma membrane Ca2+ ATPase (PMCA) and turns it into an ion channel, similar to how palytoxin turns the Na+/K+-ATPase into an ion channel. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gambierol
Gambierol is a marine polycyclic ether toxin which is produced by the dinoflagellate ''Gambierdiscus toxicus''. Gambierol is collected from the sea at the Rangiroa Peninsula in French Polynesia. The toxins are accumulated in fish through the food chain and can therefore cause human intoxication. The symptoms of the toxicity resemble those of ciguatoxins, which are extremely potent neurotoxins that bind to voltage-sensitive sodium channels and alter their function. These ciguatoxins cause ciguatera fish poisoning. Because of the resemblance, there is a possibility that gambierol is also responsible for ciguatera fish poisoning. Because the natural source of gambierol is limited, biological studies are hampered. Therefore, chemical synthesis is required. Structure and reactivity Gambierol is a ladder-shaped polyether, composed of eight ether rings, 18 stereocenters, and two challenging pyranyl rings having methyl groups that are in a 1,3-diaxial orientation to one another. Differen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brown Algae
Brown algae (singular: alga), comprising the class Phaeophyceae, are a large group of multicellular algae, including many seaweeds located in colder waters within the Northern Hemisphere. Brown algae are the major seaweeds of the temperate and polar regions. They are dominant on rocky shores throughout cooler areas of the world. Most brown algae live in marine environments, where they play an important role both as food and as a potential habitat. For instance, ''Macrocystis'', a kelp of the order Laminariales, may reach in length and forms prominent underwater kelp forests. Kelp forests like these contain a high level of biodiversity. Another example is ''Sargassum'', which creates unique floating mats of seaweed in the tropical waters of the Sargasso Sea that serve as the habitats for many species. Many brown algae, such as members of the order Fucales, commonly grow along rocky seashores. Some members of the class, such as kelps, are used by humans as food. Between 1,500 and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gambier Islands
The Gambier Islands ( or ) are an archipelago in French Polynesia, located at the southeast terminus of the Tuamotu archipelago. They cover an area of , and are made up of the Mangareva Islands, a group of high islands remnants of a caldera along with islets on the surrounding fringing reef, and the uninhabited Temoe atoll, which is located 45 km (28 mi) south-east of the Mangareva Islands. The Gambiers are generally considered a separate island group from Tuamotu both because their culture and language (Mangarevan) are much more closely related to those of the Marquesas Islands, and because, while the Tuamotus comprise several chains of coral atolls, the Mangareva Islands are of volcanic origin with central high islands. Administratively, the Gambier Islands are inside the commune of Gambier, which also includes several atolls in the Tuamotu Archipelago. The town hall (''mairie'') of the commune of Gambier is located on Mangareva, in the Gambier Islands. The population of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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