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Brevetoxin
Brevetoxin (PbTx), or brevetoxins, are a suite of cyclic polyether compounds produced naturally by a species of dinoflagellate known as ''Karenia brevis''. Brevetoxins are neurotoxins that bind to voltage-gated sodium channels in nerve cells, leading to disruption of normal neurological processes and causing the illness clinically described as neurotoxic shellfish poisoning (NSP). Although brevetoxins are most well-studied in ''K. brevis'', they are also found in other species of '' Karenia'' and at least one large fish kill has been traced to brevetoxins in '' Chattonella''. Types of brevetoxins Brevetoxins are grouped into two main types: brevetoxin A and brevetoxin B. They are further classified by what chemical substituent ( R group) is attached at certain positions within the core molecule. Other Brevetoxins *Brevetoxin-5 (PbTx-5): like brevetoxin-2, but acetylated hydroxyl group in position 38. *Brevetoxin-6 (PbTx-6): like PbTx-2, but double bond 27-28 is epoxidated ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brevetoxin A
Brevetoxin (PbTx), or brevetoxins, are a suite of cyclic polyether compounds produced naturally by a species of dinoflagellate known as '' Karenia brevis''. Brevetoxins are neurotoxins that bind to voltage-gated sodium channels in nerve cells, leading to disruption of normal neurological processes and causing the illness clinically described as neurotoxic shellfish poisoning (NSP). Although brevetoxins are most well-studied in ''K. brevis'', they are also found in other species of '' Karenia'' and at least one large fish kill has been traced to brevetoxins in '' Chattonella''. Types of brevetoxins Brevetoxins are grouped into two main types: brevetoxin A and brevetoxin B. They are further classified by what chemical substituent ( R group) is attached at certain positions within the core molecule. Other Brevetoxins *Brevetoxin-5 (PbTx-5): like brevetoxin-2, but acetylated hydroxyl group in position 38. *Brevetoxin-6 (PbTx-6): like PbTx-2, but double bond 27-28 is epoxidat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brevetoxin B
Brevetoxin (PbTx), or brevetoxins, are a suite of cyclic polyether compounds produced naturally by a species of dinoflagellate known as ''Karenia brevis''. Brevetoxins are neurotoxins that bind to voltage-gated sodium channels in nerve cells, leading to disruption of normal neurological processes and causing the illness clinically described as neurotoxic shellfish poisoning (NSP). Although brevetoxins are most well-studied in ''K. brevis'', they are also found in other species of '' Karenia'' and at least one large fish kill has been traced to brevetoxins in '' Chattonella''. Types of brevetoxins Brevetoxins are grouped into two main types: brevetoxin A and brevetoxin B. They are further classified by what chemical substituent ( R group) is attached at certain positions within the core molecule. Other Brevetoxins *Brevetoxin-5 (PbTx-5): like brevetoxin-2, but acetylated hydroxyl group in position 38. *Brevetoxin-6 (PbTx-6): like PbTx-2, but double bond 27-28 is epoxidated ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Red Tide
A harmful algal bloom (HAB), or excessive algae growth, sometimes called a red tide in marine environments, is an algal bloom that causes negative impacts to other organisms by production of natural algae-produced toxins, water deoxygenation, mechanical damage to other organisms, or by other means. HABs are sometimes defined as only those algal blooms that produce toxins, and sometimes as any algal bloom that can result in severely lower oxygen levels in natural waters, killing organisms in marine or fresh waters. Blooms can last from a few days to many months. After the bloom dies, the microbes that decompose the dead algae use up more of the oxygen, generating a " dead zone" which can cause fish die-offs. When these zones cover a large area for an extended period of time, neither fish nor plants are able to survive. It is sometimes unclear what causes specific HABs as their occurrence in some locations appears to be entirely natural, while in others they appear to be a res ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harmful Algal Bloom
A harmful algal bloom (HAB), or excessive algae growth, sometimes called a red tide in marine environments, is an algal bloom that causes negative impacts to other organisms by production of natural algae-produced toxins, water deoxygenation, mechanical damage to other organisms, or by other means. HABs are sometimes defined as only those algal blooms that produce toxins, and sometimes as any algal bloom that can result in severely lower oxygen levels in natural waters, killing organisms in marine or fresh waters. Blooms can last from a few days to many months. After the bloom dies, the microbes that decompose the dead algae use up more of the oxygen, generating a " dead zone" which can cause fish die-offs. When these zones cover a large area for an extended period of time, neither fish nor plants are able to survive. It is sometimes unclear what causes specific HABs as their occurrence in some locations appears to be entirely natural, while in others they appear to be a re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Karenia Brevis
''Karenia brevis'' is a microscopic, single-celled, photosynthetic organism in the genus '' Karenia''. It is a marine dinoflagellate commonly found in the waters of the Gulf of Mexico. It is the organism responsible for the "Florida red tides" that affect the Gulf coasts of Florida and Texas in the U.S., and nearby coasts of Mexico. ''K. brevis'' has been known to travel great lengths around the Florida peninsula and as far north as the Carolinas. Each cell has two flagella that allow it to move through the water in a spinning motion. ''K. brevis'' is unarmored, and does not contain peridinin. Cells are between 20 and 40 μm in diameter. ''K. brevis'' naturally produces a suite of potent neurotoxins collectively called brevetoxins, which cause gastrointestinal and neurological problems in other organisms and are responsible for large die-offs of marine organisms and seabirds. History The classification of ''K. brevis'' has changed over time as advances in technology are mad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurotoxic Shellfish Poisoning
Neurotoxic shellfish poisoning (NSP) is caused by the consumption of brevetoxins, which are marine toxins produced by the dinoflagellate ''Karenia brevis'' (among several others). These toxins can produce a series of gastrointestinal and neurological effects. Outbreaks of NSP commonly take place following harmful algal bloom (HAB) events, commonly referred to as "Florida red tide" (given that blooms are more commonplace along the coasts of Florida and Texas, especially during late summer and early fall). Algal blooms are a naturally-occurring phenomenon, however their frequency has been increasing in recent decades at least in-part due to human activities, climate changes, and the eutrophication (over-abundance of plant nutrients as a result of agricultural runoff, deforestation, river bed erosion, etc.) of marine waters. HABs have been occurring for all of documented history, evidenced by the Native Americans' understanding of the dangers of shellfish consumption during periods ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Karenia (dinoflagellate)
''Karenia'' is a genus that consists of unicellular, photosynthetic, planktonic organisms found in marine environments. The genus currently consists of 12 described species. They are best known for their dense toxic algal blooms and red tides that cause considerable ecological and economical damage; some ''Karenia'' species cause severe animal mortality. One species, ''Karenia brevis'', is known to cause respiratory distress and neurotoxic shellfish poisoning (NSP) in humans. Taxonomy The genus ''Karenia'' is named for Dr. Karen Steidinger for her exceptional contributions to dinoflagellate research. She has spent many decades researching ''Karenia brevis''. 12 species have been described in the genus ''Karenia'' thus far: * '' Karenia asterichroma'' * '' Karenia bicuneiformis'' * ''Karenia brevis'' * '' Karenia brevisulcata'' * '' Karenia concordia'' * '' Karenia cristata'' * '' Karenia digitata'' * '' Karenia longicanalis'' * '' Karenia mikimotoi'' * '' Karenia papilionacea'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ether
In organic chemistry, ethers are a class of compounds that contain an ether group, a single oxygen atom bonded to two separate carbon atoms, each part of an organyl group (e.g., alkyl or aryl). They have the general formula , where R and R′ represent the organyl groups. Ethers can again be classified into two varieties: if the organyl 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 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 ox ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Channel
Sodium channels are integral membrane proteins that form ion channels, conducting sodium ions (Na+) through a cell (biology), cell's cell membrane, membrane. They belong to the Cation channel superfamily, superfamily of cation channels. Classification They are classified into 2 types: Function In excitable cells such as neurons, muscle, myocytes, and certain types of glia, sodium channels are responsible for the Action potential#Stimulation and rising phase, rising phase of action potentials. These channels go through three different states called resting, active and inactive states. Even though the resting and inactive states would not allow the ions to flow through the channels the difference exists with respect to their structural conformation. Selectivity Sodium channels are highly selective for the transport of ions across cell membranes. The high selectivity with respect to the sodium ion is achieved in many different ways. All involve encapsulation of the sodium ion in a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ciguatoxin
image:ciguatoxin.svg, 300px, class=skin-invert-image, 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 seem to 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 arrhythmia, and changing the senses of heat and cold. Such poisoning from ciguatoxins is known as ciguatera. Ciguatoxins are lipophilic, able to cros ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
S-Adenosyl Methionine
''S''-Adenosyl methionine (SAM), also known under the commercial names of SAMe, SAM-e, or AdoMet, is a common cosubstrate involved in methyl group transfers, transsulfuration, and aminopropylation. Although these anabolic reactions occur throughout the body, most SAM is produced and consumed in the liver. More than 40 methyl transfers from SAM are known, to various substrates such as nucleic acids, proteins, lipids and secondary metabolites. It is made from adenosine triphosphate (ATP) and methionine by methionine adenosyltransferase. SAM was first discovered by Giulio Cantoni in 1952. In bacteria, SAM is bound by the SAM riboswitch, which regulates genes involved in methionine or cysteine biosynthesis. In eukaryotic cells, SAM serves as a regulator of a variety of processes including DNA, tRNA, and rRNA methylation; immune response; amino acid metabolism; transsulfuration; and more. In plants, SAM is crucial to the biosynthesis of ethylene, an important plant hormone ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Domoic Acid
Domoic acid (DA) is a kainic acid-type neurotoxin that causes amnesic shellfish poisoning (ASP). It is produced by algae and accumulates in shellfish, sardines, and anchovies. When sea lions, otters, cetaceans, humans, and other predators eat contaminated animals, poisoning may result. Exposure to this compound affects the brain, causing seizures, delirium and possibly death. History There has been little use of domoic acid throughout history except for in Japan, where it has been used as an anthelmintic for centuries. Domoic acid was first isolated in 1959 from a species of red algae, ''Chondria (alga), Chondria armata'', in Japan, which is commonly referred to as ''dōmoi'' (ドウモイ) in the Tokunoshima dialect, or ''hanayanagi''. Poisonings in history have been rare, or undocumented; however, it is thought that the increase in human activities is resulting in an increasing frequency of harmful algal blooms along coastlines in recent years. In 2015, the North American Pacific ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
