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Trichothecene

The trichothecenes are a large family of chemically related mycotoxins. They are produced by various species of Fusarium, Myrothecium, Trichoderma/Podostroma, Trichothecium, Cephalosporium, Verticimonosporium, and Stachybotrys. Chemically, trichothecenes are a class of sesquiterpenes.

Chemical structure of trichothecenes

The determining structural features causing the biological activity of trichothecenes are the 12,13-epoxy ring, the presence of hydroxyl or acetyl groups at appropriate positions on the trichothecene nucleus, and the structure and position of the side-chain. They are produced on many different grains such wheat, oats or maize by various Fusarium species including F. graminearum, F. sporotrichioides, F. poae and F. equiseti.

Some molds that produce trichothecene mycotoxins, for example Stachybotrys chartarum, can grow in damp indoor environments. It has been found that macrocyclic trichothecenes produced by S. chartarum can become airborne and thus contribute to health problem for building occupants.[1][2] A poisonous mushroom native to Japan and China, Podostroma cornu-damae, contains six trichothecenes, including satratoxin H, roridin E, and verrucarin.

Classification edit

General classification edit

 
The core structure of all major trichothecenes with major examples from each classification type. Identifying functional groups for the classification type are highlighted in red.

Trichothecenes are a group of over 150 chemically related mycotoxins.[3] Each trichothecene displays a core structure consisting of a single six-membered ring containing a single oxygen atom, flanked by two carbon rings.[4] This core ring structure contains an epoxide, or tricyclic ether, at the 12,13 carbon positions, as well as a double bond at the 9, 10 carbon positions.[5] These two functional groups are primarily responsible for trichothecene ability to inhibit protein synthesis and incur general cytotoxic effects.[6] Notably, this core structure is amphipathic, containing both polar and non polar parts.[7] All trichothecenes are related through this common structure, but each trichothecene also has a unique substitution pattern of oxygen containing functional groups at possible sites on carbons 3,4,7,8, and 15.[5] These functional groups govern the properties of an individual tricothecene and also serve as the basis for the most commonly used classification system for this family of toxins. This classification system breaks up the trichothecene family into four groups: Type A, B, C, and D.

Type A tricothecenes have hydroxyl, ester, or no functional group substitutions around the core ring structure.[4] Common examples of these are Neosolaniol with a hydroxyl substitution at carbon 8, and T-2 toxin with an ester substitution at carbon 8.

Type B tricothecenes are classified by the presence of carbonyl functional groups substituted around the core ring structure.[4] Common examples of these include nivalenol and trichotecin, which both have a ketone functional group at carbon 8.

Type C trichothecenes have an extra carbon 7, carbon 8 epoxide group.[4] The common example of these is crotocin. which also has an ester functional group at carbon 4.

Type D trichothecenes have an additional ring between carbon 4 and carbon 15.[4] These rings can have diverse additional functional groups. Common examples of these are roridin A and satratoxin H.

Although the distinct functional groups of these classification types give each trichothecene unique chemical properties, their classification type does not explicitly indicate their relative toxicity.[4] While Type D trichothecenes are thought to be the most toxic, Types A and B have relatively mixed toxicity.[4]

Alternative classifications edit

The classification system described above is the most commonly used to group molecules of the trichothecene family. However, a variety of alternative classification systems also exist for these complex molecules. Trichothecenes can also be generally described as simple or macrocyclic.[6] Simple trichothecenes include Types A, B, and C, whereas macrocyclic tricothecenes include Type D and are characterized by the presence of a carbon 4 – carbon 15 bridge. Additionally, J. F. Grove proposed a classification of tricothecenes into three groups that was also based upon the functional substitution patterns of the ring skeleton.[8] Group 1 tricothecenes only have functional groups substituted on the third, fully saturated carbon ring.[8] Group 2 tricothecenes contain additional functional groups on the core ring containing the 9, 10 carbon double bond.[8] Finally, Group 3 trichothecenes contain a ketone functional group at carbon 8; this is the same criteria for Type B trichothecenes.[8]

Advances in the field of evolutionary genetics have also led to the proposal of trichothecene classification systems based on the pathway of their biosynthesis. Genes responsible for the biosynthesis of a mycotoxin are typically located in clusters; in Fusariumi these are known as TRI genes.[9] TRI genes are each responsible for producing an enzyme that carries out a specific step in the biosynthesis of trichothecenes. Mutations in these genes can lead to the production of variant trichothecenes and therefore these molecules could be grouped on the basis of shared biosynthesis steps. For example, a shared step in the biosynthesis of trichothecenes is controlled by the gene TRI4.[10] This enzyme product controls the addition of either three or four oxygens to trichodiene to form either isotrichodiol or isotrichotriol respectively.[10] A variety of trichothecenes can then be synthesized from either of these intermediates and they could therefore be classified as either t-type if synthesized from isotrichotriol or d-type if synthesized from isotrichodiol.[4]

Mechanism of action edit

 
Trichothecenes accelerates reactive oxygen species production in cells, which in turn mediates the induction of the programmed cell death pathway in cells

The toxicity of tricothecenes is primarily the result of their widely cited action as protein synthesis inhibitors; this inhibition occurs at ribosomes during all three stages of protein synthesis: initiation, elongation, and termination.[11] During initiation, trichothecenes can either inhibit the association of the two ribosomal subunits, or inhibit the function of the mature ribosome by preventing the association of the first tRNA with the start codon.[11] Inhibition at elongation most likely occurs due to trichothecenes preventing the function peptidyl transferase, the enzyme which catalyzes the formation of new peptide bonds on the 60s ribosomal subunit.[12] Inhibition during termination can also be the result of peptidyl transferase inhibition or the ability of trichothecenes to prevent the hydrolysis required at this final step.[11]

It is interesting to note that the substitution pattern of the ring core of trichothecenes influences the toxin's action as either an inhibitor of initiation or as an inhibitor of elongation/termination.[11] Trichothecenes also have the ability to affect general cellular enzyme function due to the tendency of active site thiol groups to attack the 12,13 carbon epoxide ring.[13] These inhibitory effects are seen most dramatically in actively proliferating cells such as in the gastrointestinal tract or the bone marrow.

Protein synthesis occurs in both the cytoplasm of the cell as well as in the luminal space of mitochondria, the cytoplasmic organelle responsible for producing the cell's energy. This is done through an enzymatic pathway that generates highly oxidized molecules called reactive oxygen species, for example hydrogen peroxide.[14] Reactive oxygen species can react with and cause damage to many critical parts of the cell including membranes, proteins, and DNA.[15] Trichothecene inhibition of protein synthesis in the mitochondria allows reactive oxygen species to build up in the cell which inevitably leads to oxidative stress and induction of the programmed cell death pathway, apoptosis.[15]

The induction of apoptosis in cells with high levels of reactive oxygen species is due to a variety of cell signaling pathways. The first is the p53 pathway which is shown to be upregulated by the T-2 toxin. p53 is a protein responsible for controlling the cell cycle, but an increase in the activity of this protein also leads to increased activation of BAX proteins in the cell.[16] These BAX proteins are primarily responsible for increasing the permeability of the mitochondrial membrane and leading to the release of cytochrome c and reactive oxygen species.[16] Release of cytochrome c from the mitochondria induces apoptosis by initiating the assembly of caspases, or proteins responsible for degrading the cell from within.

Additionally, trichothecenes such as T-2, have also been shown to increase the c-Jun N-Terminal Kinase signaling pathway in cells.[17] Here, c-Jun N-Terminal Kinase is able to increase to phosphorylation of its target, c-Jun, into its active form. Activated c-jun acts as a transcription factor in the cell nucleus for proteins important for facilitating the downstream apoptotic pathway.[17]

Symptomology edit

The trichothecene mycotoxins are toxic to humans, other mammals, birds, fish, a variety of invertebrates, plants, and eukaryotic cells.[18] The specific toxicity varies depending on the particular toxin and animal species, however the route of administration plays a significantly higher role in determining lethality. The effects of poisoning will depend on the concentration of exposure, length of time and way the person is exposed. A highly concentrated solution or large amount of the gaseous form of the toxin is more likely to cause severe effects, including death. Upon consumption, the toxin inhibits ribosomal protein, DNA and RNA synthesis,[19][18][20] mitochondrial functions[21][22][23] cell division[24][25] while simultaneously activating a cellular stress response named ribotoxic stress response.[26]

The trichothecene mycotoxins can be absorbed though topical, oral and inhalational routes and are highly toxic at the sub-cellular, cellular, and organic system level.[18]

Trichothecenes differ from most other potential weapon toxins since they can act through the skin, which is attributed to their amphipathic and lipophilic characteristics. The small amphipathic nature of trichothecenes allows them to easily cross cell membranes[7] and interact with different organelles such as the mitochondria,[27][28] endoplasmic reticulum (ER).[29] and chloroplast[30] The lipophilic nature of trichothecenes allow them to be easily absorbed through skin[31] pulmonary mucosa, and gut. Direct dermal application or oral ingestion of trichothecene causes rapid irritation to the skin or intestinal mucosa.[19][18] As a dermal irritant and blistering agent, it is alleged to be 400 times more intoxicating than sulfur mustard.

 
Alimentary toxic aleukia response stages

The response in the body to the mycotoxin, alimentary toxic aleukia, occurs several days after consumption, in four stages:

  1. The first stage includes inflammation of the gastric and intestinal mucosa.
  2. The second stage is characterized by leukopenia, granulopenia, and progressive lymphocytosis.
  3. The third stage is characterized by the appearance of a red rash on the skin of the body, as well as hemorrhage of the skin and mucosa. If severe, aphonia and death by strangulation can occur.
  4. By the fourth stage, cells in the lymphoid organs and erythropoiesis in the bone marrow and spleen are depleted and immune response is down.

Infection can be triggered by an injury as minor as a cut, scratch or abrasion.[32]

The following symptoms are exhibited:

  • Severe itching and redness of the skin, sores, shedding of the skin
  • Distortion of any of the senses, loss of the ability to coordinate muscle movement
  • Nausea, vomiting and diarrhea
  • Nose and throat pain, discharge from the nose, itching and sneezing
  • Cough, difficulty breathing, wheezing, chest pain and spitting up blood
  • Temporary bleeding disorders
  • Elevated body temperature[33][34]

Regulatory issues edit

When it comes to animal and human food, type A trichothecenes (e.g. T-2 toxin, HT-2 toxin, diacetoxyscirpenol) are of special interest because they are more toxic than the other foodborne trichothecenes i.e. type B group (e.g. deoxynivalenol, nivalenol, 3- and 15-acetyldeoxynivalenol). However, deoxynivalenol is of concern as it is the most prevalent trichothecene in Europe.[35] The major effects of trichothecenes – related to their concentration in the commodity – are reduced feed uptake, vomiting and immuno-suppression. A relatively few countries, primarily in the European Union, have recommended maximum limits for these mycotoxins in food and animal feed. However, trichothecenes are often tested for elsewhere, in order to prevent them from entering the food chain and to prevent losses in animal production.

History edit

Trichothecenes are believed to have been discovered in 1932 in Orenburg, Russia, during World War II, by the Soviet Union. Around 100,000 people (60% mortality rate) began to suffer and die from alimentary toxic aleukia, a lethal disease with symptoms resembling radiation. It is believed that the Soviet civilians had become ill from ingesting contaminated bread, and inhaling mold through contaminated hay, dusts and ventilation systems. The culprit is believed to be the toxins Fusarium sporotrichioides and Fusarium poae which are high producers of T-2 toxin.[36] Fusarium species are probably the most commonly cited and among the most abundant of the trichothecene-producing fungi.[37]

Trichothecenes make an ideal biologic warfare agent, being lethal and inexpensive to produce in large quantities, stable as an aerosol for dispersion, and without effective vaccination/treatment.[12] Evidence suggests that mycotoxins have already been utilized as biological warfare.

  • 1964 there are unconfirmed reports that Egyptian or Russian forces used T-2 with mustard gas
  • 1974–1981 "yellow rain" incidents in southeast Asia (Laos, Cambodia) and Afghanistan[38][39][40][41]
  • 1975 and 1981 during the Vietnam War, the Soviet Union was alleged to have provided mycotoxins to the armies of Vietnam and Laos for use against resistance forces in Laos and Cambodia[42][43]
  • 1985–1989 Iran–Iraq War, reports of mycotoxin shipments to Iraq (in form of powder and smoke)[44]

Since then trichothecenes have been reported throughout the world.[45] They have had a significant economic impact on the world due to loss of human and animal life, increased health care and veterinary care costs, reduced livestock production, disposal of contaminated foods and feeds, and investment in research and applications to reduce severity of the mycotoxin problem. These mycotoxins account for millions of dollars annually in losses, due to factors that are often beyond human control (environmental, ecological, or storage method).[46]

Food contamination edit

Hazardous concentrations of trichothecenes have been detected in corn, wheat, barley, oats, rice, rye, vegetables, and other crops. Diseases resulting from infection include seed rot, seedling blight, root rot, stalk rot, and ear rot.[47] Trichothecenes are also common contaminants of poultry feeds and their adverse effects on poultry health and productivity have been studied extensively.[48]

Several studies have shown that optimal conditions for fungal growth are not necessarily optimum for toxin production.[49] Toxin production is greatest with high humidity and temperatures of 6–24 °C. The fungal propagation and production is enhanced in tropical conditions with high temperatures and moisture levels; monsoons, flash floods and unseasoned rains during harvest.[50] Trichothecenes have been detected in air samples suggesting that they can be aerosolized on spores or small particles[51][52]

Natural occurrence of TCT has been reported in Asia, Africa, South America, Europe, and North America[53]

  • Akakabibyo, a disease of similar etiology, has also been associated with trichothecene contaminated grains in Japan.[54]
  • In China, cereals or their products contaminated with trichothecenes including DON, T-2 toxin, and NIV, have also been associated with outbreaks of gastrointestinal disorders.[55]
  • In Yugoslavia, studies on mycotoxigenic fungi in raw milk have indicated that 91% of the samples tested were contaminated[56]
  • In the US, a study was conducted in seven Midwestern states in 1988–1989 and found mycotoxins in 19.5–24.7% of corn samples.[57] Since the early 1900s, incidences[spelling?] of emesis in animals and humans after consumption of cereals infected with Fusarium species have been described.[58][59]
  • In a study in the Bihar region from 1985 to 1987, 51% of the samples tested were contaminated with molds.[60]
  • In another study In the Bihar region,[61] high levels were reported in groundnut meal used for dairy cattle.
  • In Ludhiana and Punjab researchers found 75% of samples from dairy farms contaminated.[62]
  • In India, estimated 10 million dollars were lost due to groundnut contamination with mycotoxins.[63]

Safety edit

There are no known direct antidotes to trichothecene exposure. Therefore, risk management in contaminated areas is primarily defined by the treatment of exposure symptoms as well as prevention of future exposure.

Treatment edit

Typical routes of exposure to trichothecene toxins include topical absorption, ingestion, and inhalation. Severity of symptoms depends on the dose and type of exposure, but treatment is primarily focused on supporting bodily systems damaged by the mycotoxin. The first step in most exposure cases is to remove potentially contaminated clothing and to flush the sites of exposure thoroughly with water.[64] This prevents the victim from repeated exposure. Fluids and electrolytes can be given to victims with high levels of gastrointestinal damage to mitigate the effects of reduced tract absorption. Fresh air and assisted respiration can also be administered upon the development of mild respiratory distress.[64] Increasingly severe symptoms can require the application of advanced medical assistance. The onset of leukopenia, or reduction of white blood cell count, can be treated with a plasma or platelet transfusion.[64] Hypotension can be treated with the administration of norepinephrine or dopamine.[64] Development of severe cardiopulmonary distress may require intubation and additional drug treatments to stabilize heart and lung activity.

Additionally, there are a variety of chemicals that can indirectly reduce the damaging effects of trichothecenes on cells and tissues. Activated charcoal solutions are frequently administered to ingestion cases as an adsorbent.[65] Here, the charcoal acts as a porous substance for the toxin to bind, preventing its absorption through the gastrointestinal tract and increasing its removal from the body through bowel excretion. Similar detoxifying adsorbents can also be added to animal feed upon contamination to reduce the bioavailability of the toxin upon consumption. Antioxidants are also useful in mitigating the damaging effects of trichothecenes in response to the increase of reactive oxygen species they produce in cells. Generally, a good diet rich in probiotics, vitamins and nutrients, proteins, and lipidis is thought to be effective in reducing the symptoms of trichothecene poisoning.[16] For example, vitamin E was found to counteract the formation of lipid peroxides induced by T-2 toxin in chickens.[66] Similarly, cosupplementation of modified glucomannans and selenium in the diets of chickens also consuming T-2 toxin, reduced the deleterious effects of toxin associated depletion of antioxidants in the liver. Despite not being a direct antidote, these antioxidants may be critical in reducing the severity of trichothecene exposures.

Prevention edit

 
Biological approach to trichothecene decontamination. De-epoxidases are capable of reducing epoxide rings (red) to double bond groups (green) which significantly reduces the toxicity of trichothecenes.

Trichothecenes are mycotoxins produced by molds that frequently contaminate stores of grain products. This makes trichothecene contamination a significant public health problem, and many areas have strict limits on permitted trichothecene content. For example, in the European Union, only .025 ppm of T-2 toxin is permissible in bakery products intended for human consumption.[67] The molds that can produce trichothecenes grow well in dark, temperate places with high moisture content. Therefore, one of the best ways to prevent trichothecene contamination in food products is to store the resources in the proper conditions to prevent the growth of molds.[16] For example, it is generally advised to only store grains in areas with a moisture content of less than 15%.[68] However, if an area has already been contaminated with trichothecene toxins, there are a variety of possible decontamination strategies to prevent further exposure. Treatment with 1% sodium hypochlorite (NaOCl) in 0.1M sodium hydroxide (NaOH) for 4–5 hours has been shown to inhibit the biological activity of T-2 toxin.[16] Incubation with aqueous ozone at approximately 25 ppm has also been shown to degrade a variety of trichothecenes through a mechanism involving oxidation of the 9, 10 carbon double bond.[69] UV exposure has also been shown to be effective under the right conditions.[16]

Outside of the strategies for physical and chemical decontamination, advancing research in molecular genetics has also given rise to the potential of a biological decontamination approach. Many microbes, including bacteria, yeast, and fungi, have evolved enzymatic gene products which facilitate the specific and efficient degradation of trichothecene mycotoxins.[68] Many of these enzymes specifically degrade the 12,13 carbon epoxide ring which is important for the toxicity of trichothecenes. For example, the Eubacteria strain BBSH 797 produces de-epoxidase enzymes which reduce the 12,13 carbon epoxide ring to a double bond group.[68] These, along with other microbes expressing trichothecene detoxifying properties, can be used in feed stores to prevent to toxic effect of contaminated feed upon consumption.[16] Furthermore, molecular cloning of the genes responsible for producing these detoxifying enzymes could be useful in producing strains of agricultural products that are resistant to trichothecene poisoning.[16]

Epoxitrichothecenes edit

Epoxitrichothecenes are a variation of the above, and were once explored for military use in East Germany, and possibly the whole Soviet bloc.[70] There is no feasible treatment once symptoms of epoxithichothecene poisoning set in, though the effects can subside without leaving any permanent damage.

The plans for use as a large-scale bioweapon were dropped, as the relevant epoxitrichothecenes degrade very quickly under UV light and heat, as well as chlorine exposure, making them useless for open attacks and the poisoning of water supplies.[citation needed]

References edit

  1. ^ Detection of Airborne Stachybotrys chartarum Macrocyclic Trichothecene Mycotoxins in the Indoor Environment
  2. ^ Etzel RA (2002). "Mycotoxins". JAMA. 287 (4): 425–7. doi:10.1001/jama.287.4.425. PMID 11798344.
  3. ^ . American Phytopathological Society. Archived from the original on 2018-05-07. Retrieved 2018-05-07.
  4. ^ a b c d e f g h McCormick SP, Stanley AM, Stover NA, Alexander NJ (July 2011). "Trichothecenes: from simple to complex mycotoxins". Toxins. 3 (7): 802–14. doi:10.3390/toxins3070802. PMC 3202860. PMID 22069741.
  5. ^ a b Protection Against Trichothecene Mycotoxins. National Academies. 1983-01-01. ISBN 9780309034302.
  6. ^ a b Bennett JW, Klich M (July 2003). "Mycotoxins". Clinical Microbiology Reviews. 16 (3): 497–516. doi:10.1128/CMR.16.3.497-516.2003. PMC 164220. PMID 12857779.
  7. ^ a b Middlebrook JL, Leatherman DL (September 1989). "Specific association of T-2 toxin with mammalian cells". Biochemical Pharmacology. 38 (18): 3093–102. doi:10.1016/0006-2952(89)90020-8. PMID 2783163.
  8. ^ a b c d Grove JF (1988). "Non-macrocyclic trichothecenes". Natural Product Reports. 5 (2): 187–209. doi:10.1039/NP9880500187. ISSN 0265-0568. PMID 3062504.
  9. ^ Kimura, Makoto; Tokai, Takeshi; o'Donnell, Kerry; Ward, Todd J.; Fujimura, Makoto; Hamamoto, Hiroshi; Shibata, Takehiko; Yamaguchi, Isamu (2003-03-27). "The trichothecene biosynthesis gene cluster of Fusarium graminearum F15 contains a limited number of essential pathway genes and expressed non-essential genes". FEBS Letters. 539 (1–3): 105–110. doi:10.1016/S0014-5793(03)00208-4. PMID 12650935. S2CID 19787988.
  10. ^ a b McCormick SP, Alexander NJ, Proctor RH (July 2006). "Fusarium Tri4 encodes a multifunctional oxygenase required for trichothecene biosynthesis". Canadian Journal of Microbiology. 52 (7): 636–42. doi:10.1139/w06-011. PMID 16917519.
  11. ^ a b c d Kiessling K (1986). "Biochemical mechanism of action of mycotoxins" (PDF). Pure and Applied Chemistry. 58 (2): 327–338. doi:10.1351/pac198658020327. S2CID 94777285.
  12. ^ a b Henghold WB (July 2004). "Other biologic toxin bioweapons: ricin, staphylococcal enterotoxin B, and trichothecene mycotoxins". Dermatologic Clinics. 22 (3): 257–62, v. doi:10.1016/j.det.2004.03.004. PMID 15207307.
  13. ^ Ueno Y, Matsumoto H (October 1975). "Inactivation of some thiol-enzymes by trichothecene mycotoxins from Fusarium species". Chemical & Pharmaceutical Bulletin. 23 (10): 2439–42. doi:10.1248/cpb.23.2439. PMID 1212759.
  14. ^ Zorov DB, Juhaszova M, Sollott SJ (July 2014). "Mitochondrial reactive oxygen species (ROS) and ROS-induced ROS release". Physiological Reviews. 94 (3): 909–50. doi:10.1152/physrev.00026.2013. PMC 4101632. PMID 24987008.
  15. ^ a b Fang H, Wu Y, Guo J, Rong J, Ma L, Zhao Z, Zuo D, Peng S (August 2012). "T-2 toxin induces apoptosis in differentiated murine embryonic stem cells through reactive oxygen species-mediated mitochondrial pathway". Apoptosis. 17 (8): 895–907. doi:10.1007/s10495-012-0724-3. PMID 22614820. S2CID 17446994.
  16. ^ a b c d e f g h Adhikari M, Negi B, Kaushik N, Adhikari A, Al-Khedhairy AA, Kaushik NK, Choi EH (May 2017). "T-2 mycotoxin: toxicological effects and decontamination strategies". Oncotarget. 8 (20): 33933–33952. doi:10.18632/oncotarget.15422. PMC 5464924. PMID 28430618.
  17. ^ a b Li M, Pestka JJ (September 2008). "Comparative induction of 28S ribosomal RNA cleavage by ricin and the trichothecenes deoxynivalenol and T-2 toxin in the macrophage". Toxicological Sciences. 105 (1): 67–78. doi:10.1093/toxsci/kfn111. PMC 2734305. PMID 18535001.
  18. ^ a b c d Wannemacher R, Wiener SL, Sidell FR, Takafuji ET, Franz DR (1997). "Medical Aspects of Chemical and Biological Warfare". Trichothecene mycotoxins. Vol. 6 (1st ed.). United States Government Printing. pp. 655–76. ISBN 978-9997320919.
  19. ^ a b McLaughlin C, Vaughan M, Campbell I, Wei CM, Stafford M, Hansen B (1977). "Inhibition of protein synthesis by trichothecenes.". Mycotoxins in human and animal health. Park Forest South, IL: Pathotox Publishers. pp. 263–75.
  20. ^ Desjardins AE, Hohn TM, McCormick SP (September 1993). "Trichothecene biosynthesis in Fusarium species: chemistry, genetics, and significance". Microbiological Reviews. 57 (3): 595–604. doi:10.1128/MMBR.57.3.595-604.1993. PMC 372927. PMID 8246841.
  21. ^ Fried HM, Warner JR (January 1981). "Cloning of yeast gene for trichodermin resistance and ribosomal protein L3". Proceedings of the National Academy of Sciences of the United States of America. 78 (1): 238–42. Bibcode:1981PNAS...78..238F. doi:10.1073/pnas.78.1.238. PMC 319027. PMID 7017711.
  22. ^ Bouaziz C, Martel C, Sharaf el dein O, Abid-Essefi S, Brenner C, Lemaire C, Bacha H (August 2009). "Fusarial toxin-induced toxicity in cultured cells and in isolated mitochondria involves PTPC-dependent activation of the mitochondrial pathway of apoptosis". Toxicological Sciences. 110 (2): 363–75. doi:10.1093/toxsci/kfp117. PMID 19541794.
  23. ^ Bin-Umer MA, McLaughlin JE, Basu D, McCormick S, Tumer NE (December 2011). "Trichothecene mycotoxins inhibit mitochondrial translation--implication for the mechanism of toxicity". Toxins. 3 (12): 1484–501. doi:10.3390/toxins3121484. PMC 3268453. PMID 22295173.
  24. ^ Azcona-Olivera JI, Ouyang Y, Murtha J, Chu FS, Pestka JJ (July 1995). "Induction of cytokine mRNAs in mice after oral exposure to the trichothecene vomitoxin (deoxynivalenol): relationship to toxin distribution and protein synthesis inhibition". Toxicology and Applied Pharmacology. 133 (1): 109–20. doi:10.1006/taap.1995.1132. PMID 7597700.
  25. ^ Thompson WL, Wannemacher RW (1986). "Structure-function relationships of 12,13-epoxytrichothecene mycotoxins in cell culture: comparison to whole animal lethality". Toxicon. 24 (10): 985–94. doi:10.1016/0041-0101(86)90004-8. PMID 3824405.
  26. ^ Shifrin VI, Anderson P (May 1999). "Trichothecene mycotoxins trigger a ribotoxic stress response that activates c-Jun N-terminal kinase and p38 mitogen-activated protein kinase and induces apoptosis". The Journal of Biological Chemistry. 274 (20): 13985–92. doi:10.1074/jbc.274.20.13985. PMID 10318810.
  27. ^ Cundliffe E, Cannon M, Davies J (January 1974). "Mechanism of inhibition of eukaryotic protein synthesis by trichothecene fungal toxins". Proceedings of the National Academy of Sciences of the United States of America. 71 (1): 30–4. Bibcode:1974PNAS...71...30C. doi:10.1073/pnas.71.1.30. PMC 387925. PMID 4521056.
  28. ^ Cundliffe E, Davies JE (March 1977). "Inhibition of initiation, elongation, and termination of eukaryotic protein synthesis by trichothecene fungal toxins". Antimicrobial Agents and Chemotherapy. 11 (3): 491–9. doi:10.1128/AAC.11.3.491. PMC 352012. PMID 856003.
  29. ^ Ueno Y (1985). "The toxicology of mycotoxins". Critical Reviews in Toxicology. 14 (2): 99–132. doi:10.3109/10408448509089851. PMID 3158480.
  30. ^ Pace JG, Watts MR, Canterbury WJ (1988). "T-2 mycotoxin inhibits mitochondrial protein synthesis". Toxicon. 26 (1): 77–85. doi:10.1016/0041-0101(88)90139-0. PMID 3347933.
  31. ^ Coulombe RA (March 1993). "Biological action of mycotoxins". Journal of Dairy Science. 76 (3): 880–91. doi:10.3168/jds.S0022-0302(93)77414-7. PMID 8463495.
  32. ^ Schwarzer K (2009). "Harmful effects of mycotoxins on animal physiology". 17th Annual ASAIM SEA Feed Technology and Nutrition Workshop. Hue, Vietnam.{{cite book}}: CS1 maint: location missing publisher (link)
  33. ^ "Trichothecene Mycotoxin | IDPH". www.dph.illinois.gov. Retrieved 2018-05-07.
  34. ^ Ueno Y (April 1984). "Toxicological features of T-2 toxin and related trichothecenes". Fundamental and Applied Toxicology. 4 (2 Pt 2): S124–32. doi:10.1016/0272-0590(84)90144-1. PMID 6609858.
  35. ^ Miller JD (2003). "Aspects of the ecology of fusarium toxins in cereals.". In de Vries JW, Trucksess MW, Jakson LS (eds.). Mycotoxins and Food Safety. New York: Kluwer Academic/Plenum Publishers. pp. 19–27.
  36. ^ Joffe AZ (1950). Toxicity of fungi on cereals overwintered in the field: on the etiology of alimentary toxic aleukia (Ph.D.). Leningrad: Inst. Bot. Acad. Sci. p. 205.
  37. ^ Rocha O, Ansari K, Doohan FM (April 2005). "Effects of trichothecene mycotoxins on eukaryotic cells: a review". Food Additives and Contaminants. 22 (4): 369–78. doi:10.1080/02652030500058403. PMID 16019807. S2CID 1534222.
  38. ^ Heyndrickx A, Sookvanichsilp N, Van den Heede M (1984). "Detection of trichothecene mycotoxins (yellow rain) in blood, urine and faeces of Iranian soldiers treated as victims of a gas attack". Archives Belges = Belgisch Archief. Suppl: 143–6. PMID 6535464.
  39. ^ Mirocha CJ, Pawlosky RA, Chatterjee K, Watson S, Hayes W (November 1983). "Analysis for Fusarium toxins in various samples implicated in biological warfare in Southeast Asia". Journal of the Association of Official Analytical Chemists. 66 (6): 1485–99. PMID 6643363.
  40. ^ Spyker MS, Spyker DA (October 1983). "Yellow rain: chemical warfare in Southeast Asia and Afghanistan". Veterinary and Human Toxicology. 25 (5): 335–40. PMID 6636506.
  41. ^ Wannemacher JR, Wiener SL. "Chapter 34,: Trichothecene Mycotoxins". In Sidell FR, Takafuji ET, Franz DR (eds.). Medical Aspects Of Chemical And Biological Warfare. Textbook of Military Medicine series. Office of The Surgeon General, Department of the Army, United States of America.
  42. ^ Haig AM (March 22, 1982). Special Report 98: Chemical Warfare in Southeast Asia and Afghanistan: Report to the Congress from Secretary of State Haig (Report). Washington, DC: US Government Printing Office.
  43. ^ Tucker JB (2001). "The yellow rain controversy: lessons for arms control compliance". Nonproliferation Rev. 8: 25–39. doi:10.1080/10736700108436836. S2CID 22473397.
  44. ^ "CNS - Obtain Microbial Seed Stock for Standard or Novel Agent". webarchive.loc.gov. Archived from the original on 2001-11-27. Retrieved 2018-05-06.
  45. ^ Dohnal V, Jezkova A, Jun D, Kuca K (January 2008). "Metabolic pathways of T-2 toxin". Current Drug Metabolism. 9 (1): 77–82. doi:10.2174/138920008783331176. PMID 18220574.
  46. ^ Zain, Mohamed E. (2011-04-01). "Impact of mycotoxins on humans and animals". Journal of Saudi Chemical Society. 15 (2): 129–144. doi:10.1016/j.jscs.2010.06.006. ISSN 1319-6103.
  47. ^ Schollenberger M, Müller HM, Ernst K, Sondermann S, Liebscher M, Schlecker C, Wischer G, Drochner W, Hartung K, Piepho HP (October 2012). "Occurrence and distribution of 13 trichothecene toxins in naturally contaminated maize plants in Germany". Toxins. 4 (10): 778–87. doi:10.3390/toxins4100778. PMC 3496988. PMID 23162697.
  48. ^ Leeson S, Dias GJ, Summers JD (1995). "Tricothecenes". Poultry Metabolic Disorders. Guelph, Ontario, Canada. pp. 190–226.{{cite book}}: CS1 maint: location missing publisher (link)
  49. ^ Hesseltine CW, Shotwell OL, Smith M, Ellis JJ, Vandegraft E, Shannon G (1970). "Production of various aflatoxins by strains of the Aspergillis flavus series.". Proc. first US–Japan Conf. Toxic Microorg. Washington.{{cite book}}: CS1 maint: location missing publisher (link)
  50. ^ Dudeja P, Gupta RK, Minhas AS (eds.). Food Safety in the 21st Century: Public Health Perspective.
  51. ^ Brasel TL, Douglas DR, Wilson SC, Straus DC (January 2005). "Detection of airborne Stachybotrys chartarum macrocyclic trichothecene mycotoxins on particulates smaller than conidia". Applied and Environmental Microbiology. 71 (1): 114–22. Bibcode:2005ApEnM..71..114B. doi:10.1128/AEM.71.1.114-122.2005. PMC 544211. PMID 15640178.
  52. ^ Cho S, Seo S, Schmechel D, Grinshpun SA, Reponen T (September 2005). "Aerodynamic characteristics and respiratory deposition of fungal fragments". Atmospheric Environment. 39 (30): 5454–5465. Bibcode:2005AtmEn..39.5454C. doi:10.1016/j.atmosenv.2005.05.042.
  53. ^ Beasley VR, ed. (1989). Tricothecene Mycotoxicosis: Pathophysiologic Effects. Vol. 1. Boca Raton: CRC Press. pp. 1–26.
  54. ^ Ueno Y, Ishii K, Sakai K, Kanaeda S, Tsunoda H (1972). "Toxicological approaches to the metabolites of Fusaria. IV. Microbial survey on "bean-hulls poisoning of horses" with the isolation of toxic trichothecenes, neosolaniol and T-2 toxin of Fusarium solani M-1-1". Japanese J. Exp. Med. 42 (3): 187–203. PMID 4538152.
  55. ^ Lou XY (1988). "Fusarium toxins contamination of cereals in China". Proc. Japanese Assoc. Mycotoxicology. Suppl. 1: 97–98.
  56. ^ Skrinjar M, Danev M, Dimic G (1995). "Investigation on the presence of toxigenic fungi and aflatoxins in raw milk". Acta Aliment. 24: 395–402.
  57. ^ Russell L, Cox DF, Larsen G, Bodwell K, Nelson CE (January 1991). "Incidence of molds and mycotoxins in commercial animal feed mills in seven midwestern states, 1988–1989". Journal of Animal Science. 69 (1): 5–12. doi:10.2527/1991.6915. PMID 1825995.
  58. ^ Naumov NA (1916). "Intoxicating bread". Min. Yeml. (Russia), Trudy Ruiri Miwel. I. Fitopatol. Uchen, Kom.: 216.
  59. ^ Dounin M (1930). "The fusariosis of cereal crops in European-Russia in 1923". Phytopathol. 16: 305–308.
  60. ^ Ranjan KS, Sinha AK (1991). "Occurrence of mycotoxigenic fungi and mycotoxins in animal feed from bihar, India". Journal of the Science of Food and Agriculture. 56 (1): 39–47. doi:10.1002/jsfa.2740560105.
  61. ^ Phillips SI, Wareing PW, Dutta A, Panigrahi S, Medlock V (1996-01-01). "The mycoflora and incidence of aflatoxin, zearalenone and sterigmatocystin in dairy feed and forage samples from Eastern India and Bangladesh". Mycopathologia. 133 (1): 15–21. doi:10.1007/BF00437094. ISSN 0301-486X. S2CID 32084324.
  62. ^ Dhand NK, Joshi DB, Jand SK (1998). "Aflatoxins in dairy feeds/ingredients". Ind. J. Anim. Nutr. 15: 285–286.
  63. ^ Vasanthi S, Bhat RV (November 1998). "Mycotoxins in foods—occurrence, health & economic significance & food control measures". The Indian Journal of Medical Research. 108: 212–24. PMID 9863277.
  64. ^ a b c d "T-2 TOXIN – National Library of Medicine HSDB Database". toxnet.nlm.nih.gov. Retrieved 2018-05-07.
  65. ^ Edrington TS, Kubena LF, Harvey RB, Rottinghaus GE (September 1997). "Influence of a superactivated charcoal on the toxic effects of aflatoxin or T-2 toxin in growing broilers". Poultry Science. 76 (9): 1205–11. doi:10.1093/ps/76.9.1205. PMID 9276881.
  66. ^ Hoehler D, Marquardt RR (December 1996). "Influence of vitamins E and C on the toxic effects of ochratoxin A and T-2 toxin in chicks". Poultry Science. 75 (12): 1508–15. doi:10.3382/ps.0751508. PMID 9000276.
  67. ^ Stoev SD (March 2015). "Foodborne mycotoxicoses, risk assessment and underestimated hazard of masked mycotoxins and joint mycotoxin effects or interaction". Environmental Toxicology and Pharmacology. 39 (2): 794–809. doi:10.1016/j.etap.2015.01.022. PMID 25734690.
  68. ^ a b c Devreese M, De Backer P, Croubels S (2013). "Different methods to counteract mycotoxin production and its impact on animal health". Vlaams Diergen Tijds. 82 (4): 181–190. doi:10.21825/vdt.v82i4.16695.
  69. ^ Young JC, Zhu H, Zhou T (March 2006). "Degradation of trichothecene mycotoxins by aqueous ozone". Food and Chemical Toxicology. 44 (3): 417–24. doi:10.1016/j.fct.2005.08.015. PMID 16185803.
  70. ^ Die Chemie der Kampfstoffe, GDR Government publishing, 1988

External links edit

  • Robert W. Wannemacher and Stanley L. Weiner: Trichothecene mycotoxins, chapter 34, Medical Aspects of Chemical and Biological Warfare 2018-04-18 at the Wayback Machine

trichothecene, this, article, needs, additional, citations, verification, please, help, improve, this, article, adding, citations, reliable, sources, unsourced, material, challenged, removed, find, sources, news, newspapers, books, scholar, jstor, october, 200. This article needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed Find sources Trichothecene news newspapers books scholar JSTOR October 2008 Learn how and when to remove this template message The trichothecenes are a large family of chemically related mycotoxins They are produced by various species of Fusarium Myrothecium Trichoderma Podostroma Trichothecium Cephalosporium Verticimonosporium and Stachybotrys Chemically trichothecenes are a class of sesquiterpenes Chemical structure of trichothecenesThe determining structural features causing the biological activity of trichothecenes are the 12 13 epoxy ring the presence of hydroxyl or acetyl groups at appropriate positions on the trichothecene nucleus and the structure and position of the side chain They are produced on many different grains such wheat oats or maize by various Fusarium species including F graminearum F sporotrichioides F poae and F equiseti Some molds that produce trichothecene mycotoxins for example Stachybotrys chartarum can grow in damp indoor environments It has been found that macrocyclic trichothecenes produced by S chartarum can become airborne and thus contribute to health problem for building occupants 1 2 A poisonous mushroom native to Japan and China Podostroma cornu damae contains six trichothecenes including satratoxin H roridin E and verrucarin Contents 1 Classification 1 1 General classification 1 2 Alternative classifications 2 Mechanism of action 3 Symptomology 4 Regulatory issues 5 History 6 Food contamination 7 Safety 7 1 Treatment 7 2 Prevention 8 Epoxitrichothecenes 9 References 10 External linksClassification editGeneral classification edit nbsp The core structure of all major trichothecenes with major examples from each classification type Identifying functional groups for the classification type are highlighted in red Trichothecenes are a group of over 150 chemically related mycotoxins 3 Each trichothecene displays a core structure consisting of a single six membered ring containing a single oxygen atom flanked by two carbon rings 4 This core ring structure contains an epoxide or tricyclic ether at the 12 13 carbon positions as well as a double bond at the 9 10 carbon positions 5 These two functional groups are primarily responsible for trichothecene ability to inhibit protein synthesis and incur general cytotoxic effects 6 Notably this core structure is amphipathic containing both polar and non polar parts 7 All trichothecenes are related through this common structure but each trichothecene also has a unique substitution pattern of oxygen containing functional groups at possible sites on carbons 3 4 7 8 and 15 5 These functional groups govern the properties of an individual tricothecene and also serve as the basis for the most commonly used classification system for this family of toxins This classification system breaks up the trichothecene family into four groups Type A B C and D Type A tricothecenes have hydroxyl ester or no functional group substitutions around the core ring structure 4 Common examples of these are Neosolaniol with a hydroxyl substitution at carbon 8 and T 2 toxin with an ester substitution at carbon 8 Type B tricothecenes are classified by the presence of carbonyl functional groups substituted around the core ring structure 4 Common examples of these include nivalenol and trichotecin which both have a ketone functional group at carbon 8 Type C trichothecenes have an extra carbon 7 carbon 8 epoxide group 4 The common example of these is crotocin which also has an ester functional group at carbon 4 Type D trichothecenes have an additional ring between carbon 4 and carbon 15 4 These rings can have diverse additional functional groups Common examples of these are roridin A and satratoxin H Although the distinct functional groups of these classification types give each trichothecene unique chemical properties their classification type does not explicitly indicate their relative toxicity 4 While Type D trichothecenes are thought to be the most toxic Types A and B have relatively mixed toxicity 4 Alternative classifications edit The classification system described above is the most commonly used to group molecules of the trichothecene family However a variety of alternative classification systems also exist for these complex molecules Trichothecenes can also be generally described as simple or macrocyclic 6 Simple trichothecenes include Types A B and C whereas macrocyclic tricothecenes include Type D and are characterized by the presence of a carbon 4 carbon 15 bridge Additionally J F Grove proposed a classification of tricothecenes into three groups that was also based upon the functional substitution patterns of the ring skeleton 8 Group 1 tricothecenes only have functional groups substituted on the third fully saturated carbon ring 8 Group 2 tricothecenes contain additional functional groups on the core ring containing the 9 10 carbon double bond 8 Finally Group 3 trichothecenes contain a ketone functional group at carbon 8 this is the same criteria for Type B trichothecenes 8 Advances in the field of evolutionary genetics have also led to the proposal of trichothecene classification systems based on the pathway of their biosynthesis Genes responsible for the biosynthesis of a mycotoxin are typically located in clusters in Fusariumi these are known as TRI genes 9 TRI genes are each responsible for producing an enzyme that carries out a specific step in the biosynthesis of trichothecenes Mutations in these genes can lead to the production of variant trichothecenes and therefore these molecules could be grouped on the basis of shared biosynthesis steps For example a shared step in the biosynthesis of trichothecenes is controlled by the gene TRI4 10 This enzyme product controls the addition of either three or four oxygens to trichodiene to form either isotrichodiol or isotrichotriol respectively 10 A variety of trichothecenes can then be synthesized from either of these intermediates and they could therefore be classified as either t type if synthesized from isotrichotriol or d type if synthesized from isotrichodiol 4 Mechanism of action edit nbsp Trichothecenes accelerates reactive oxygen species production in cells which in turn mediates the induction of the programmed cell death pathway in cellsThe toxicity of tricothecenes is primarily the result of their widely cited action as protein synthesis inhibitors this inhibition occurs at ribosomes during all three stages of protein synthesis initiation elongation and termination 11 During initiation trichothecenes can either inhibit the association of the two ribosomal subunits or inhibit the function of the mature ribosome by preventing the association of the first tRNA with the start codon 11 Inhibition at elongation most likely occurs due to trichothecenes preventing the function peptidyl transferase the enzyme which catalyzes the formation of new peptide bonds on the 60s ribosomal subunit 12 Inhibition during termination can also be the result of peptidyl transferase inhibition or the ability of trichothecenes to prevent the hydrolysis required at this final step 11 It is interesting to note that the substitution pattern of the ring core of trichothecenes influences the toxin s action as either an inhibitor of initiation or as an inhibitor of elongation termination 11 Trichothecenes also have the ability to affect general cellular enzyme function due to the tendency of active site thiol groups to attack the 12 13 carbon epoxide ring 13 These inhibitory effects are seen most dramatically in actively proliferating cells such as in the gastrointestinal tract or the bone marrow Protein synthesis occurs in both the cytoplasm of the cell as well as in the luminal space of mitochondria the cytoplasmic organelle responsible for producing the cell s energy This is done through an enzymatic pathway that generates highly oxidized molecules called reactive oxygen species for example hydrogen peroxide 14 Reactive oxygen species can react with and cause damage to many critical parts of the cell including membranes proteins and DNA 15 Trichothecene inhibition of protein synthesis in the mitochondria allows reactive oxygen species to build up in the cell which inevitably leads to oxidative stress and induction of the programmed cell death pathway apoptosis 15 The induction of apoptosis in cells with high levels of reactive oxygen species is due to a variety of cell signaling pathways The first is the p53 pathway which is shown to be upregulated by the T 2 toxin p53 is a protein responsible for controlling the cell cycle but an increase in the activity of this protein also leads to increased activation of BAX proteins in the cell 16 These BAX proteins are primarily responsible for increasing the permeability of the mitochondrial membrane and leading to the release of cytochrome c and reactive oxygen species 16 Release of cytochrome c from the mitochondria induces apoptosis by initiating the assembly of caspases or proteins responsible for degrading the cell from within Additionally trichothecenes such as T 2 have also been shown to increase the c Jun N Terminal Kinase signaling pathway in cells 17 Here c Jun N Terminal Kinase is able to increase to phosphorylation of its target c Jun into its active form Activated c jun acts as a transcription factor in the cell nucleus for proteins important for facilitating the downstream apoptotic pathway 17 Symptomology editThe trichothecene mycotoxins are toxic to humans other mammals birds fish a variety of invertebrates plants and eukaryotic cells 18 The specific toxicity varies depending on the particular toxin and animal species however the route of administration plays a significantly higher role in determining lethality The effects of poisoning will depend on the concentration of exposure length of time and way the person is exposed A highly concentrated solution or large amount of the gaseous form of the toxin is more likely to cause severe effects including death Upon consumption the toxin inhibits ribosomal protein DNA and RNA synthesis 19 18 20 mitochondrial functions 21 22 23 cell division 24 25 while simultaneously activating a cellular stress response named ribotoxic stress response 26 The trichothecene mycotoxins can be absorbed though topical oral and inhalational routes and are highly toxic at the sub cellular cellular and organic system level 18 Trichothecenes differ from most other potential weapon toxins since they can act through the skin which is attributed to their amphipathic and lipophilic characteristics The small amphipathic nature of trichothecenes allows them to easily cross cell membranes 7 and interact with different organelles such as the mitochondria 27 28 endoplasmic reticulum ER 29 and chloroplast 30 The lipophilic nature of trichothecenes allow them to be easily absorbed through skin 31 pulmonary mucosa and gut Direct dermal application or oral ingestion of trichothecene causes rapid irritation to the skin or intestinal mucosa 19 18 As a dermal irritant and blistering agent it is alleged to be 400 times more intoxicating than sulfur mustard nbsp Alimentary toxic aleukia response stagesThe response in the body to the mycotoxin alimentary toxic aleukia occurs several days after consumption in four stages The first stage includes inflammation of the gastric and intestinal mucosa The second stage is characterized by leukopenia granulopenia and progressive lymphocytosis The third stage is characterized by the appearance of a red rash on the skin of the body as well as hemorrhage of the skin and mucosa If severe aphonia and death by strangulation can occur By the fourth stage cells in the lymphoid organs and erythropoiesis in the bone marrow and spleen are depleted and immune response is down Infection can be triggered by an injury as minor as a cut scratch or abrasion 32 The following symptoms are exhibited Severe itching and redness of the skin sores shedding of the skin Distortion of any of the senses loss of the ability to coordinate muscle movement Nausea vomiting and diarrhea Nose and throat pain discharge from the nose itching and sneezing Cough difficulty breathing wheezing chest pain and spitting up blood Temporary bleeding disorders Elevated body temperature 33 34 Regulatory issues editWhen it comes to animal and human food type A trichothecenes e g T 2 toxin HT 2 toxin diacetoxyscirpenol are of special interest because they are more toxic than the other foodborne trichothecenes i e type B group e g deoxynivalenol nivalenol 3 and 15 acetyldeoxynivalenol However deoxynivalenol is of concern as it is the most prevalent trichothecene in Europe 35 The major effects of trichothecenes related to their concentration in the commodity are reduced feed uptake vomiting and immuno suppression A relatively few countries primarily in the European Union have recommended maximum limits for these mycotoxins in food and animal feed However trichothecenes are often tested for elsewhere in order to prevent them from entering the food chain and to prevent losses in animal production History editTrichothecenes are believed to have been discovered in 1932 in Orenburg Russia during World War II by the Soviet Union Around 100 000 people 60 mortality rate began to suffer and die from alimentary toxic aleukia a lethal disease with symptoms resembling radiation It is believed that the Soviet civilians had become ill from ingesting contaminated bread and inhaling mold through contaminated hay dusts and ventilation systems The culprit is believed to be the toxins Fusarium sporotrichioides and Fusarium poae which are high producers of T 2 toxin 36 Fusarium species are probably the most commonly cited and among the most abundant of the trichothecene producing fungi 37 Trichothecenes make an ideal biologic warfare agent being lethal and inexpensive to produce in large quantities stable as an aerosol for dispersion and without effective vaccination treatment 12 Evidence suggests that mycotoxins have already been utilized as biological warfare 1964 there are unconfirmed reports that Egyptian or Russian forces used T 2 with mustard gas 1974 1981 yellow rain incidents in southeast Asia Laos Cambodia and Afghanistan 38 39 40 41 1975 and 1981 during the Vietnam War the Soviet Union was alleged to have provided mycotoxins to the armies of Vietnam and Laos for use against resistance forces in Laos and Cambodia 42 43 1985 1989 Iran Iraq War reports of mycotoxin shipments to Iraq in form of powder and smoke 44 Since then trichothecenes have been reported throughout the world 45 They have had a significant economic impact on the world due to loss of human and animal life increased health care and veterinary care costs reduced livestock production disposal of contaminated foods and feeds and investment in research and applications to reduce severity of the mycotoxin problem These mycotoxins account for millions of dollars annually in losses due to factors that are often beyond human control environmental ecological or storage method 46 Food contamination editHazardous concentrations of trichothecenes have been detected in corn wheat barley oats rice rye vegetables and other crops Diseases resulting from infection include seed rot seedling blight root rot stalk rot and ear rot 47 Trichothecenes are also common contaminants of poultry feeds and their adverse effects on poultry health and productivity have been studied extensively 48 Several studies have shown that optimal conditions for fungal growth are not necessarily optimum for toxin production 49 Toxin production is greatest with high humidity and temperatures of 6 24 C The fungal propagation and production is enhanced in tropical conditions with high temperatures and moisture levels monsoons flash floods and unseasoned rains during harvest 50 Trichothecenes have been detected in air samples suggesting that they can be aerosolized on spores or small particles 51 52 Natural occurrence of TCT has been reported in Asia Africa South America Europe and North America 53 Akakabibyo a disease of similar etiology has also been associated with trichothecene contaminated grains in Japan 54 In China cereals or their products contaminated with trichothecenes including DON T 2 toxin and NIV have also been associated with outbreaks of gastrointestinal disorders 55 In Yugoslavia studies on mycotoxigenic fungi in raw milk have indicated that 91 of the samples tested were contaminated 56 In the US a study was conducted in seven Midwestern states in 1988 1989 and found mycotoxins in 19 5 24 7 of corn samples 57 Since the early 1900s incidences spelling of emesis in animals and humans after consumption of cereals infected with Fusarium species have been described 58 59 In a study in the Bihar region from 1985 to 1987 51 of the samples tested were contaminated with molds 60 In another study In the Bihar region 61 high levels were reported in groundnut meal used for dairy cattle In Ludhiana and Punjab researchers found 75 of samples from dairy farms contaminated 62 In India estimated 10 million dollars were lost due to groundnut contamination with mycotoxins 63 Safety editThere are no known direct antidotes to trichothecene exposure Therefore risk management in contaminated areas is primarily defined by the treatment of exposure symptoms as well as prevention of future exposure Treatment edit Typical routes of exposure to trichothecene toxins include topical absorption ingestion and inhalation Severity of symptoms depends on the dose and type of exposure but treatment is primarily focused on supporting bodily systems damaged by the mycotoxin The first step in most exposure cases is to remove potentially contaminated clothing and to flush the sites of exposure thoroughly with water 64 This prevents the victim from repeated exposure Fluids and electrolytes can be given to victims with high levels of gastrointestinal damage to mitigate the effects of reduced tract absorption Fresh air and assisted respiration can also be administered upon the development of mild respiratory distress 64 Increasingly severe symptoms can require the application of advanced medical assistance The onset of leukopenia or reduction of white blood cell count can be treated with a plasma or platelet transfusion 64 Hypotension can be treated with the administration of norepinephrine or dopamine 64 Development of severe cardiopulmonary distress may require intubation and additional drug treatments to stabilize heart and lung activity Additionally there are a variety of chemicals that can indirectly reduce the damaging effects of trichothecenes on cells and tissues Activated charcoal solutions are frequently administered to ingestion cases as an adsorbent 65 Here the charcoal acts as a porous substance for the toxin to bind preventing its absorption through the gastrointestinal tract and increasing its removal from the body through bowel excretion Similar detoxifying adsorbents can also be added to animal feed upon contamination to reduce the bioavailability of the toxin upon consumption Antioxidants are also useful in mitigating the damaging effects of trichothecenes in response to the increase of reactive oxygen species they produce in cells Generally a good diet rich in probiotics vitamins and nutrients proteins and lipidis is thought to be effective in reducing the symptoms of trichothecene poisoning 16 For example vitamin E was found to counteract the formation of lipid peroxides induced by T 2 toxin in chickens 66 Similarly cosupplementation of modified glucomannans and selenium in the diets of chickens also consuming T 2 toxin reduced the deleterious effects of toxin associated depletion of antioxidants in the liver Despite not being a direct antidote these antioxidants may be critical in reducing the severity of trichothecene exposures Prevention edit nbsp Biological approach to trichothecene decontamination De epoxidases are capable of reducing epoxide rings red to double bond groups green which significantly reduces the toxicity of trichothecenes Trichothecenes are mycotoxins produced by molds that frequently contaminate stores of grain products This makes trichothecene contamination a significant public health problem and many areas have strict limits on permitted trichothecene content For example in the European Union only 025 ppm of T 2 toxin is permissible in bakery products intended for human consumption 67 The molds that can produce trichothecenes grow well in dark temperate places with high moisture content Therefore one of the best ways to prevent trichothecene contamination in food products is to store the resources in the proper conditions to prevent the growth of molds 16 For example it is generally advised to only store grains in areas with a moisture content of less than 15 68 However if an area has already been contaminated with trichothecene toxins there are a variety of possible decontamination strategies to prevent further exposure Treatment with 1 sodium hypochlorite NaOCl in 0 1M sodium hydroxide NaOH for 4 5 hours has been shown to inhibit the biological activity of T 2 toxin 16 Incubation with aqueous ozone at approximately 25 ppm has also been shown to degrade a variety of trichothecenes through a mechanism involving oxidation of the 9 10 carbon double bond 69 UV exposure has also been shown to be effective under the right conditions 16 Outside of the strategies for physical and chemical decontamination advancing research in molecular genetics has also given rise to the potential of a biological decontamination approach Many microbes including bacteria yeast and fungi have evolved enzymatic gene products which facilitate the specific and efficient degradation of trichothecene mycotoxins 68 Many of these enzymes specifically degrade the 12 13 carbon epoxide ring which is important for the toxicity of trichothecenes For example the Eubacteria strain BBSH 797 produces de epoxidase enzymes which reduce the 12 13 carbon epoxide ring to a double bond group 68 These along with other microbes expressing trichothecene detoxifying properties can be used in feed stores to prevent to toxic effect of contaminated feed upon consumption 16 Furthermore molecular cloning of the genes responsible for producing these detoxifying enzymes could be useful in producing strains of agricultural products that are resistant to trichothecene poisoning 16 Epoxitrichothecenes editEpoxitrichothecenes are a variation of the above and were once explored for military use in East Germany and possibly the whole Soviet bloc 70 There is no feasible treatment once symptoms of epoxithichothecene poisoning set in though the effects can subside without leaving any permanent damage The plans for use as a large scale bioweapon were dropped as the relevant epoxitrichothecenes degrade very quickly under UV light and heat as well as chlorine exposure making them useless for open attacks and the poisoning of water supplies citation needed References edit Detection of Airborne Stachybotrys chartarum Macrocyclic Trichothecene Mycotoxins in the Indoor Environment Etzel RA 2002 Mycotoxins JAMA 287 4 425 7 doi 10 1001 jama 287 4 425 PMID 11798344 American Phytopathological Society American Phytopathological Society Archived from the original on 2018 05 07 Retrieved 2018 05 07 a b c d e f g h McCormick SP Stanley AM Stover NA Alexander NJ July 2011 Trichothecenes from simple to complex mycotoxins Toxins 3 7 802 14 doi 10 3390 toxins3070802 PMC 3202860 PMID 22069741 a b Protection Against Trichothecene Mycotoxins National Academies 1983 01 01 ISBN 9780309034302 a b Bennett JW Klich M July 2003 Mycotoxins Clinical Microbiology Reviews 16 3 497 516 doi 10 1128 CMR 16 3 497 516 2003 PMC 164220 PMID 12857779 a b Middlebrook JL Leatherman DL September 1989 Specific association of T 2 toxin with mammalian cells Biochemical Pharmacology 38 18 3093 102 doi 10 1016 0006 2952 89 90020 8 PMID 2783163 a b c d Grove JF 1988 Non macrocyclic trichothecenes Natural Product Reports 5 2 187 209 doi 10 1039 NP9880500187 ISSN 0265 0568 PMID 3062504 Kimura Makoto Tokai Takeshi o Donnell Kerry Ward Todd J Fujimura Makoto Hamamoto Hiroshi Shibata Takehiko Yamaguchi Isamu 2003 03 27 The trichothecene biosynthesis gene cluster of Fusarium graminearum F15 contains a limited number of essential pathway genes and expressed non essential genes FEBS Letters 539 1 3 105 110 doi 10 1016 S0014 5793 03 00208 4 PMID 12650935 S2CID 19787988 a b McCormick SP Alexander NJ Proctor RH July 2006 Fusarium Tri4 encodes a multifunctional oxygenase required for trichothecene biosynthesis Canadian Journal of Microbiology 52 7 636 42 doi 10 1139 w06 011 PMID 16917519 a b c d Kiessling K 1986 Biochemical mechanism of action of mycotoxins PDF Pure and Applied Chemistry 58 2 327 338 doi 10 1351 pac198658020327 S2CID 94777285 a b Henghold WB July 2004 Other biologic toxin bioweapons ricin staphylococcal enterotoxin B and trichothecene mycotoxins Dermatologic Clinics 22 3 257 62 v doi 10 1016 j det 2004 03 004 PMID 15207307 Ueno Y Matsumoto H October 1975 Inactivation of some thiol enzymes by trichothecene mycotoxins from Fusarium species Chemical amp Pharmaceutical Bulletin 23 10 2439 42 doi 10 1248 cpb 23 2439 PMID 1212759 Zorov DB Juhaszova M Sollott SJ July 2014 Mitochondrial reactive oxygen species ROS and ROS induced ROS release Physiological Reviews 94 3 909 50 doi 10 1152 physrev 00026 2013 PMC 4101632 PMID 24987008 a b Fang H Wu Y Guo J Rong J Ma L Zhao Z Zuo D Peng S August 2012 T 2 toxin induces apoptosis in differentiated murine embryonic stem cells through reactive oxygen species mediated mitochondrial pathway Apoptosis 17 8 895 907 doi 10 1007 s10495 012 0724 3 PMID 22614820 S2CID 17446994 a b c d e f g h Adhikari M Negi B Kaushik N Adhikari A Al Khedhairy AA Kaushik NK Choi EH May 2017 T 2 mycotoxin toxicological effects and decontamination strategies Oncotarget 8 20 33933 33952 doi 10 18632 oncotarget 15422 PMC 5464924 PMID 28430618 a b Li M Pestka JJ September 2008 Comparative induction of 28S ribosomal RNA cleavage by ricin and the trichothecenes deoxynivalenol and T 2 toxin in the macrophage Toxicological Sciences 105 1 67 78 doi 10 1093 toxsci kfn111 PMC 2734305 PMID 18535001 a b c d Wannemacher R Wiener SL Sidell FR Takafuji ET Franz DR 1997 Medical Aspects of Chemical and Biological Warfare Trichothecene mycotoxins Vol 6 1st ed United States Government Printing pp 655 76 ISBN 978 9997320919 a b McLaughlin C Vaughan M Campbell I Wei CM Stafford M Hansen B 1977 Inhibition of protein synthesis by trichothecenes Mycotoxins in human and animal health Park Forest South IL Pathotox Publishers pp 263 75 Desjardins AE Hohn TM McCormick SP September 1993 Trichothecene biosynthesis in Fusarium species chemistry genetics and significance Microbiological Reviews 57 3 595 604 doi 10 1128 MMBR 57 3 595 604 1993 PMC 372927 PMID 8246841 Fried HM Warner JR January 1981 Cloning of yeast gene for trichodermin resistance and ribosomal protein L3 Proceedings of the National Academy of Sciences of the United States of America 78 1 238 42 Bibcode 1981PNAS 78 238F doi 10 1073 pnas 78 1 238 PMC 319027 PMID 7017711 Bouaziz C Martel C Sharaf el dein O Abid Essefi S Brenner C Lemaire C Bacha H August 2009 Fusarial toxin induced toxicity in cultured cells and in isolated mitochondria involves PTPC dependent activation of the mitochondrial pathway of apoptosis Toxicological Sciences 110 2 363 75 doi 10 1093 toxsci kfp117 PMID 19541794 Bin Umer MA McLaughlin JE Basu D McCormick S Tumer NE December 2011 Trichothecene mycotoxins inhibit mitochondrial translation implication for the mechanism of toxicity Toxins 3 12 1484 501 doi 10 3390 toxins3121484 PMC 3268453 PMID 22295173 Azcona Olivera JI Ouyang Y Murtha J Chu FS Pestka JJ July 1995 Induction of cytokine mRNAs in mice after oral exposure to the trichothecene vomitoxin deoxynivalenol relationship to toxin distribution and protein synthesis inhibition Toxicology and Applied Pharmacology 133 1 109 20 doi 10 1006 taap 1995 1132 PMID 7597700 Thompson WL Wannemacher RW 1986 Structure function relationships of 12 13 epoxytrichothecene mycotoxins in cell culture comparison to whole animal lethality Toxicon 24 10 985 94 doi 10 1016 0041 0101 86 90004 8 PMID 3824405 Shifrin VI Anderson P May 1999 Trichothecene mycotoxins trigger a ribotoxic stress response that activates c Jun N terminal kinase and p38 mitogen activated protein kinase and induces apoptosis The Journal of Biological Chemistry 274 20 13985 92 doi 10 1074 jbc 274 20 13985 PMID 10318810 Cundliffe E Cannon M Davies J January 1974 Mechanism of inhibition of eukaryotic protein synthesis by trichothecene fungal toxins Proceedings of the National Academy of Sciences of the United States of America 71 1 30 4 Bibcode 1974PNAS 71 30C doi 10 1073 pnas 71 1 30 PMC 387925 PMID 4521056 Cundliffe E Davies JE March 1977 Inhibition of initiation elongation and termination of eukaryotic protein synthesis by trichothecene fungal toxins Antimicrobial Agents and Chemotherapy 11 3 491 9 doi 10 1128 AAC 11 3 491 PMC 352012 PMID 856003 Ueno Y 1985 The toxicology of mycotoxins Critical Reviews in Toxicology 14 2 99 132 doi 10 3109 10408448509089851 PMID 3158480 Pace JG Watts MR Canterbury WJ 1988 T 2 mycotoxin inhibits mitochondrial protein synthesis Toxicon 26 1 77 85 doi 10 1016 0041 0101 88 90139 0 PMID 3347933 Coulombe RA March 1993 Biological action of mycotoxins Journal of Dairy Science 76 3 880 91 doi 10 3168 jds S0022 0302 93 77414 7 PMID 8463495 Schwarzer K 2009 Harmful effects of mycotoxins on animal physiology 17th Annual ASAIM SEA Feed Technology and Nutrition Workshop Hue Vietnam a href Template Cite book html title Template Cite book cite book a CS1 maint location missing publisher link Trichothecene Mycotoxin IDPH www dph illinois gov Retrieved 2018 05 07 Ueno Y April 1984 Toxicological features of T 2 toxin and related trichothecenes Fundamental and Applied Toxicology 4 2 Pt 2 S124 32 doi 10 1016 0272 0590 84 90144 1 PMID 6609858 Miller JD 2003 Aspects of the ecology of fusarium toxins in cereals In de Vries JW Trucksess MW Jakson LS eds Mycotoxins and Food Safety New York Kluwer Academic Plenum Publishers pp 19 27 Joffe AZ 1950 Toxicity of fungi on cereals overwintered in the field on the etiology of alimentary toxic aleukia Ph D Leningrad Inst Bot Acad Sci p 205 Rocha O Ansari K Doohan FM April 2005 Effects of trichothecene mycotoxins on eukaryotic cells a review Food Additives and Contaminants 22 4 369 78 doi 10 1080 02652030500058403 PMID 16019807 S2CID 1534222 Heyndrickx A Sookvanichsilp N Van den Heede M 1984 Detection of trichothecene mycotoxins yellow rain in blood urine and faeces of Iranian soldiers treated as victims of a gas attack Archives Belges Belgisch Archief Suppl 143 6 PMID 6535464 Mirocha CJ Pawlosky RA Chatterjee K Watson S Hayes W November 1983 Analysis for Fusarium toxins in various samples implicated in biological warfare in Southeast Asia Journal of the Association of Official Analytical Chemists 66 6 1485 99 PMID 6643363 Spyker MS Spyker DA October 1983 Yellow rain chemical warfare in Southeast Asia and Afghanistan Veterinary and Human Toxicology 25 5 335 40 PMID 6636506 Wannemacher JR Wiener SL Chapter 34 Trichothecene Mycotoxins In Sidell FR Takafuji ET Franz DR eds Medical Aspects Of Chemical And Biological Warfare Textbook of Military Medicine series Office of The Surgeon General Department of the Army United States of America Haig AM March 22 1982 Special Report 98 Chemical Warfare in Southeast Asia and Afghanistan Report to the Congress from Secretary of State Haig Report Washington DC US Government Printing Office Tucker JB 2001 The yellow rain controversy lessons for arms control compliance Nonproliferation Rev 8 25 39 doi 10 1080 10736700108436836 S2CID 22473397 CNS Obtain Microbial Seed Stock for Standard or Novel Agent webarchive loc gov Archived from the original on 2001 11 27 Retrieved 2018 05 06 Dohnal V Jezkova A Jun D Kuca K January 2008 Metabolic pathways of T 2 toxin Current Drug Metabolism 9 1 77 82 doi 10 2174 138920008783331176 PMID 18220574 Zain Mohamed E 2011 04 01 Impact of mycotoxins on humans and animals Journal of Saudi Chemical Society 15 2 129 144 doi 10 1016 j jscs 2010 06 006 ISSN 1319 6103 Schollenberger M Muller HM Ernst K Sondermann S Liebscher M Schlecker C Wischer G Drochner W Hartung K Piepho HP October 2012 Occurrence and distribution of 13 trichothecene toxins in naturally contaminated maize plants in Germany Toxins 4 10 778 87 doi 10 3390 toxins4100778 PMC 3496988 PMID 23162697 Leeson S Dias GJ Summers JD 1995 Tricothecenes Poultry Metabolic Disorders Guelph Ontario Canada pp 190 226 a href Template Cite book html title Template Cite book cite book a CS1 maint location missing publisher link Hesseltine CW Shotwell OL Smith M Ellis JJ Vandegraft E Shannon G 1970 Production of various aflatoxins by strains of the Aspergillis flavus series Proc first US Japan Conf Toxic Microorg Washington a href Template Cite book html title Template Cite book cite book a CS1 maint location missing publisher link Dudeja P Gupta RK Minhas AS eds Food Safety in the 21st Century Public Health Perspective Brasel TL Douglas DR Wilson SC Straus DC January 2005 Detection of airborne Stachybotrys chartarum macrocyclic trichothecene mycotoxins on particulates smaller than conidia Applied and Environmental Microbiology 71 1 114 22 Bibcode 2005ApEnM 71 114B doi 10 1128 AEM 71 1 114 122 2005 PMC 544211 PMID 15640178 Cho S Seo S Schmechel D Grinshpun SA Reponen T September 2005 Aerodynamic characteristics and respiratory deposition of fungal fragments Atmospheric Environment 39 30 5454 5465 Bibcode 2005AtmEn 39 5454C doi 10 1016 j atmosenv 2005 05 042 Beasley VR ed 1989 Tricothecene Mycotoxicosis Pathophysiologic Effects Vol 1 Boca Raton CRC Press pp 1 26 Ueno Y Ishii K Sakai K Kanaeda S Tsunoda H 1972 Toxicological approaches to the metabolites of Fusaria IV Microbial survey on bean hulls poisoning of horses with the isolation of toxic trichothecenes neosolaniol and T 2 toxin of Fusarium solani M 1 1 Japanese J Exp Med 42 3 187 203 PMID 4538152 Lou XY 1988 Fusarium toxins contamination of cereals in China Proc Japanese Assoc Mycotoxicology Suppl 1 97 98 Skrinjar M Danev M Dimic G 1995 Investigation on the presence of toxigenic fungi and aflatoxins in raw milk Acta Aliment 24 395 402 Russell L Cox DF Larsen G Bodwell K Nelson CE January 1991 Incidence of molds and mycotoxins in commercial animal feed mills in seven midwestern states 1988 1989 Journal of Animal Science 69 1 5 12 doi 10 2527 1991 6915 PMID 1825995 Naumov NA 1916 Intoxicating bread Min Yeml Russia Trudy Ruiri Miwel I Fitopatol Uchen Kom 216 Dounin M 1930 The fusariosis of cereal crops in European Russia in 1923 Phytopathol 16 305 308 Ranjan KS Sinha AK 1991 Occurrence of mycotoxigenic fungi and mycotoxins in animal feed from bihar India Journal of the Science of Food and Agriculture 56 1 39 47 doi 10 1002 jsfa 2740560105 Phillips SI Wareing PW Dutta A Panigrahi S Medlock V 1996 01 01 The mycoflora and incidence of aflatoxin zearalenone and sterigmatocystin in dairy feed and forage samples from Eastern India and Bangladesh Mycopathologia 133 1 15 21 doi 10 1007 BF00437094 ISSN 0301 486X S2CID 32084324 Dhand NK Joshi DB Jand SK 1998 Aflatoxins in dairy feeds ingredients Ind J Anim Nutr 15 285 286 Vasanthi S Bhat RV November 1998 Mycotoxins in foods occurrence health amp economic significance amp food control measures The Indian Journal of Medical Research 108 212 24 PMID 9863277 a b c d T 2 TOXIN National Library of Medicine HSDB Database toxnet nlm nih gov Retrieved 2018 05 07 Edrington TS Kubena LF Harvey RB Rottinghaus GE September 1997 Influence of a superactivated charcoal on the toxic effects of aflatoxin or T 2 toxin in growing broilers Poultry Science 76 9 1205 11 doi 10 1093 ps 76 9 1205 PMID 9276881 Hoehler D Marquardt RR December 1996 Influence of vitamins E and C on the toxic effects of ochratoxin A and T 2 toxin in chicks Poultry Science 75 12 1508 15 doi 10 3382 ps 0751508 PMID 9000276 Stoev SD March 2015 Foodborne mycotoxicoses risk assessment and underestimated hazard of masked mycotoxins and joint mycotoxin effects or interaction Environmental Toxicology and Pharmacology 39 2 794 809 doi 10 1016 j etap 2015 01 022 PMID 25734690 a b c Devreese M De Backer P Croubels S 2013 Different methods to counteract mycotoxin production and its impact on animal health Vlaams Diergen Tijds 82 4 181 190 doi 10 21825 vdt v82i4 16695 Young JC Zhu H Zhou T March 2006 Degradation of trichothecene mycotoxins by aqueous ozone Food and Chemical Toxicology 44 3 417 24 doi 10 1016 j fct 2005 08 015 PMID 16185803 Die Chemie der Kampfstoffe GDR Government publishing 1988External links editStructures of some of the Commoner Trichothecene Mycotoxins Robert W Wannemacher and Stanley L Weiner Trichothecene mycotoxins chapter 34 Medical Aspects of Chemical and Biological Warfare Archived 2018 04 18 at the Wayback Machine Retrieved from https en wikipedia org w index php title Trichothecene amp oldid 1188128677, wikipedia, wiki, book, books, library,

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