Identifiers | |
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3D model (JSmol) | |
Abbreviations | AZA |
ChemSpider | |
PubChem CID | |
UNII | |
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Properties | |
C47H71NO12 | |
Molar mass | 842.07 g mol-1 |
Appearance | Colorless |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Azaspiracids (AZA) are a group of polycyclic ether marine algal toxins produced by the small dinoflagellate Azadinium spinosum that can accumulate in shellfish and thereby cause illness in humans. [1] [2]
Azaspiracid was first identified in the 1990s following an outbreak of human illness in the Netherlands that was associated with ingestion of contaminated shellfish originating from Killary Harbour, Ireland. To date, over 20 AZA analogues have been identified in phytoplankton and shellfish. [3] [4] [5] [6] [7] [8] [9] [10] Over the last 15 years, AZAs have been reported in shellfish from many coastal regions of western Europe, [11] [12] [13] [14] [15] Northern Africa, [16] [17] South America, [18] [19] and North America. In addition, AZAs have been found in Japanese sponges [20] and Scandinavian crabs. [21] Not surprisingly, the global distribution of AZAs appears to correspond to the apparent wide spread occurrence of Azadinium. [22] [23] [24] Empirical evidence is now available that unambiguously demonstrates the accumulation of AZAs in shellfish via direct feeding on AZA-producing A. spinosum. [25] [26]
Azaspiracid is a phycotoxin that inhibits hERG voltage-gated potassium channels. [27]
Unlike many other marine phycotoxins, little is known about the AZA toxin class. Similar to DSP toxins, human consumption of AZA-contaminated shellfish can result in severe acute symptoms that include nausea, vomiting, diarrhea, and stomach cramps. [13] Azaspiracid has an EU established regulatory limit of 160 μg/kg. Within the United States, the FDA has established an action level for AZP of 0.16ppm (160 μg/kg) azaspiracid equivalents which is consistent with that currently employed in the EU. To date, six human azaspiracid poisoning (AZP) events have been confirmed, but it is quite possible, due to the similarity of symptoms observed for people with DSP or other types of food poisoning (e.g., bacterial enteritis), that many more undocumented events have occurred. Coincidentally, each of the confirmed AZP events have been traced to contaminated Irish shellfish (Mytilus edulis).
The first confirmed AZP event occurred in November 1995. Mussels harvested from Killary Harbour, Ireland were exported to The Netherlands, resulting in eight people falling ill with DSP-like symptoms of gastrointestinal illness, including nausea, vomiting, severe diarrhea, and stomach cramps. [3] [28] [29] The absence of known DSP toxins okadaic acid and dinophysistoxin-2 led to the discovery and identification of a novel etiological agent, temporarily called Killary Toxin-3 before being renamed to AZA1. [3] Mussels collected from the same area five months after the event were shown to contain (in μg/g whole meat) AZA1 (1.14), AZA2 (0.23), and AZA3 (0.06). [9]
In September/October 1997, as few as 10-12 AZA-contaminated mussels were consumed by individuals in the Arranmore Island region of Donegal, Ireland. At least 20-24 people were believed to have been exposed to AZAs in this event, but only eight sought medical attention. Symptoms included nausea, vomiting, and diarrhea for 2–5 days prior to full recovery. Analysis of the shellfish revealed five AZA analogues, AZA1-5, with most of the toxin concentrated in the digestive glands [8] [9] at levels exceeding 30 μg/g (estimated at 6 μg/g whole mussel meat). The AZAs persisted in the mussels at elevated levels for at least eight months.[ citation needed ]
In September 1998, mussels exported from Clew Bay, Ireland to Ravenna, Italy were consumed and ten people fell victim to AZP with typical gastrointestinal symptoms. Digestive glands were shown to contain ~1 μg/g AZAtotal with three AZA analogues present (in μg/g digestive gland): AZA1 (0.5), AZA2 (0.06), and AZA3 (0.44).[ citation needed ]
Also in September 1998, a large shipment of mussels from Bantry Bay, Ireland was sent to France, resulting in an estimated 20-30 human illnesses due to AZP. Ironically, these shellfish has been tested ahead of time and deemed safe according to the DSP mouse bioassay; however, it was later determined that the DSP mouse bioassay is susceptible to false negatives for the AZA toxins. Coincidentally, the French government posed an embargo on the import of Irish shellfish for most of 1999. Follow-up analysis of the shellfish by LC/MS determined that high levels of AZA were present (up to 1.5 μg/g whole meat).[ citation needed ]
In August 2000, between 12-16 people from various regions (Warrington, Alyesbury, Isle of Wight, Sheffield) of the United Kingdom were intoxicated following the consumption of frozen, pre-cooked mussels that originated from Bantry Bay, Ireland. Symptoms included nausea, diarrhea, abdominal pain, and cramps. These mussels were also deemed safe for human consumption based on results from mouse bioassays; however, LC/MS analysis determined the presence of AZA1-3 in an uneaten portion from this same batch. Toxin concentrations were 0.85 μg/g shellfish meat (not including the digestive gland), which likely represented an underestimation of the total concentration. [28]
In 2008, an AZP event occurred in the United States in July. Frozen, pre-cooked mussels from Bantry Bay, Ireland were exported and intoxicated two people. It is estimated that each person ate between 113 and 340 grams of shellfish. Within five hours following the meal, each person experienced abdominal heaviness, vomiting (5-15 times), and diarrhea for up to 30 hours. Analysis of similar products with the same lot number revealed the presence of AZA1-3 with up to 0.244 μg AZAtotal/g tissue. [30] As a result of this event, over 150 tonnes of commercial product were removed from the market and voluntarily destroyed by the manufacturer.[ citation needed ]
The general structure of AZA1 (MW 841.5) was first reported in 1998 after successful isolation from Irish blue mussel (Mytilus edulis) material. [3] A cyclic amine (or aza group), a unique tri-spiro-assembly and a carboxylic acid group gave rise to the name AZA-SPIR-ACID. The original structure reported in 1998 was found to contain several errors, first indicted by an empirical demonstration of the contra-thermodynamic configurational assignment of the relative configuration at the C13 ketal center, [31] and followed by attempts carried out in 2003. [32] [33] The purported synthesized AZA1 structure was found to have a different chromatographic behavior and discrepancies in its nuclear magnetic resonance (NMR) spectrum compared to the compound isolated from natural sources. Further extensive study including sophisticated synthetic chemistry resulted in structure revision in 2004. [34] [35] [36] In 2018, a comprehensive synthetic and analytical study was published that provided a structural revision that corrects all previous published azaspiracid structural assignments. [37] Specifically, the primary azaspiracids were assigned the (6R,10R,13R,14R,16R,17R,19S,20S,21R,24S,25S,28S,30S,32R,33R,34R,36S,37S,39R)-absolute configurations. Thus, the structures of azaspiracids presented on this Wikipedia page should also be revised to reflect the 20S absolute configuration.
A toxin is a naturally occurring poison produced by metabolic activities of living cells or organisms. They occur especially as proteins, often conjugated. The term was first used by organic chemist Ludwig Brieger (1849–1919), derived from toxic.
Mussel is the common name used for members of several families of bivalve molluscs, from saltwater and freshwater habitats. These groups have in common a shell whose outline is elongated and asymmetrical compared with other edible clams, which are often more or less rounded or oval.
Tetrodotoxin (TTX) is a potent neurotoxin. Its name derives from Tetraodontiformes, an order that includes pufferfish, porcupinefish, ocean sunfish, and triggerfish; several of these species carry the toxin. Although tetrodotoxin was discovered in these fish, it is found in several other animals. It is also produced by certain infectious or symbiotic bacteria like Pseudoalteromonas, Pseudomonas, and Vibrio as well as other species found in symbiotic relationships with animals and plants.
The blue mussel, also known as the common mussel, is a medium-sized edible marine bivalve mollusc in the family Mytilidae, the only extant family in the order Mytilida, known as "true mussels". Blue mussels are subject to commercial use and intensive aquaculture. A species with a large range, empty shells are commonly found on beaches around the world.
Saxitoxin (STX) is a potent neurotoxin and the best-known paralytic shellfish toxin. Ingestion of saxitoxin by humans, usually by consumption of shellfish contaminated by toxic algal blooms, is responsible for the illness known as paralytic shellfish poisoning (PSP).
Palytoxin, PTX or PLTX is an intense vasoconstrictor, and is considered to be one of the most poisonous non-protein substances known, second only to maitotoxin in terms of toxicity in mice.
Okadaic acid, C44H68O13, is a toxin produced by several species of dinoflagellates, and is known to accumulate in both marine sponges and shellfish. One of the primary causes of diarrhetic shellfish poisoning, okadaic acid is a potent inhibitor of specific protein phosphatases and is known to have a variety of negative effects on cells. A polyketide, polyether derivative of a C38 fatty acid, okadaic acid and other members of its family have shined light upon many biological processes both with respect to dinoflagellete polyketide synthesis as well as the role of protein phosphatases in cell growth.
Paralytic shellfish poisoning (PSP) is one of the four recognized syndromes of shellfish poisoning, which share some common features and are primarily associated with bivalve mollusks. These shellfish are filter feeders and accumulate neurotoxins, chiefly saxitoxin, produced by microscopic algae, such as dinoflagellates, diatoms, and cyanobacteria. Dinoflagellates of the genus Alexandrium are the most numerous and widespread saxitoxin producers and are responsible for PSP blooms in subarctic, temperate, and tropical locations. The majority of toxic blooms have been caused by the morphospecies Alexandrium catenella, Alexandrium tamarense, Gonyaulax catenella and Alexandrium fundyense, which together comprise the A. tamarense species complex. In Asia, PSP is mostly associated with the occurrence of the species Pyrodinium bahamense.
Amnesic shellfish poisoning (ASP) is an illness caused by consumption of shellfish that contain the marine biotoxin called domoic acid. In mammals, including humans, domoic acid acts as a neurotoxin, causing permanent short-term memory loss, brain damage, and death in severe cases.
The California mussel is a large edible mussel, a marine bivalve mollusk in the family Mytilidae.
The Chilean mussel or Chilean blue mussel, Mytilus chilensis, is a species of blue mussel native to the coasts of Chile from Biobío Region to Cape Horn. Genomic evidence has confirmed that the native Chilean blue mussel is genetically distinct from the Northern Hemisphere M. edulis, M. galloprovincialis and M. trossulus and also genetically different from Mytilus platensis,the other species of smooth shelled mussel from South America.
Leukoma staminea, commonly known as the Pacific littleneck clam, the littleneck clam, the rock cockle, the hardshell clam, the Tomales Bay cockle, the rock clam or the ribbed carpet shell, is a species of bivalve mollusc in the family Veneridae. This species of mollusc was exploited by early humans in North America; for example, the Chumash peoples of Central California harvested these clams in Morro Bay approximately 1,000 years ago, and the distinctive shells form middens near their settlements.
Mytilus is a cosmopolitan genus of medium to large-sized edible, mainly saltwater mussels, marine bivalve molluscs in the family Mytilidae.
Yessotoxins are a group of lipophilic, sulfur bearing polyether toxins that are related to ciguatoxins. They are produced by a variety of dinoflagellates, most notably Lingulodinium polyedrum and Gonyaulax spinifera.
The Mediterranean mussel is a species of bivalve, a marine mollusc in the family Mytilidae. It is an invasive species in many parts of the world, and also an object of aquaculture.
Saxidomus gigantea is a large, edible saltwater clam, a marine bivalve mollusk in the family Veneridae, the venus clams. It can be found along the western coast of North America, ranging from the Aleutian Islands to San Francisco Bay. Common names for this clam include butter clam, Washington clam, smooth Washington clam and money shell.
Azadinium spinosum is a species of dinoflagellates that produces azaspiracid toxins, particularly AZA 1, AZA 2 and an isomer of AZA 2.
Dinophysis acuta is a species of flagellated planktons belonging to the genus Dinophysis. It is one of the few unusual photosynthetic protists that acquire plastids from algae by endosymbiosis. By forming massive blooms, particularly in late summer and spring, it causes red tides. It produces toxic substances and the red tides cause widespread infection of seafood, particularly crabs and mussels. When infected animals are consumed, severe diarrhoea occurs. The clinical symptom is called diarrhetic shellfish poisoning. The main chemical toxins were identified in 2006 as okadaic acid and pectenotoxins. They can produce non-fatal or fatal amounts of toxins in their predators, which can become toxic to humans.
Decarbamoylsaxitoxin, abbreviated as dcSTX, is a neurotoxin which is naturally produced in dinoflagellate. DcSTX is one of the many analogues of saxitoxin (STX).
Prymnesin-2 is an organic compound that is secreted by the haptophyte Prymnesium parvum. It belongs to the prymnesin family and has potent hemolytic and ichthyotoxic properties. In a purified form it appears as a pale yellow solid. P. parvum is responsible for red harmful algal blooms worldwide, causing massive fish killings. When these algal blooms occur, this compound poses a threat to the local fishing industry. This is especially true for brackish water, as the compound can reach critical concentrations more easily.