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| Other names (-)-Viriditoxin (M)-Viriditoxin | |
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3D model (JSmol) | |
| ChEBI | |
| ChemSpider | |
PubChem CID | |
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CompTox Dashboard (EPA) | |
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
Viriditoxin (VDT [1] [2] ) is a secondary metabolite produced by fungi. [3] Viriditoxin is a type of mycotoxin. [1] The biosynthesis of the compound has been investigated. [3]
It is produced by several Aspergillus species including A. aureoluteus , [4] A. brevipes , [5] and A. viridinutans in which it was first identified in 1971. [6] It has been isolated from Paecilomyces variotii , which was obtained from Nomura's jellyfish. [2] It is also produced by Cladosporium cladosporioides . [1]
Natural viriditoxin exists as a single atropisomer owing to restricted rotation about the C-C bond which joins the two naphthol rings. It has been confirmed by total synthesis to be twisted into the so-called M isomer. [6]
Viriditoxin is a secondary metabolite, a polyketide produced from multiple acetyl-CoA and malonyl-CoA units which are combined by a polyketide synthase (PKS) enzyme complex. A chain of eight acetate units are cyclised to give the three-ring system which forms half of the carbon framework of the final product. After selective methylation of one of the phenol groups and reduction of the pyrone ring, the resulting intermediate (semiviriditoxin) is dimerised by a laccase enzyme, generating specifically the minus M atropisomer. [7]
In nature, viriditoxin likely is used against microbial competition. On mangroves, P. variotii's production of viriditoxin was linked to antagonism against bacteria. [3]
Secondary metabolites, also called specialised metabolites, toxins, secondary products, or natural products, are organic compounds produced by any lifeform, e.g. bacteria, fungi, animals, or plants, which are not directly involved in the normal growth, development, or reproduction of the organism. Instead, they generally mediate ecological interactions, which may produce a selective advantage for the organism by increasing its survivability or fecundity. Specific secondary metabolites are often restricted to a narrow set of species within a phylogenetic group. Secondary metabolites often play an important role in plant defense against herbivory and other interspecies defenses. Humans use secondary metabolites as medicines, flavourings, pigments, and recreational drugs.
Aspergillus niger is a mold classified within the Nigri section of the Aspergillus genus. The Aspergillus genus consists of common molds found throughout the environment within soil and water, on vegetation, in fecal matter, on decomposing matter, and suspended in the air. Species within this genus often grow quickly and can sporulate within a few days of germination. A combination of characteristics unique to A. niger makes the microbe invaluable to the production of many acids, proteins and bioactive compounds. Characteristics including extensive metabolic diversity, high production yield, secretion capability, and the ability to conduct post-translational modifications are responsible for A. niger's robust production of secondary metabolites. A. niger's capability to withstand extremely acidic conditions makes it especially important to the industrial production of citric acid.
In organic chemistry, polyketides are a class of natural products derived from a precursor molecule consisting of a chain of alternating ketone and methylene groups: [−C(=O)−CH2−]n. First studied in the early 20th century, discovery, biosynthesis, and application of polyketides has evolved. It is a large and diverse group of secondary metabolites caused by its complex biosynthesis which resembles that of fatty acid synthesis. Because of this diversity, polyketides can have various medicinal, agricultural, and industrial applications. Many polyketides are medicinal or exhibit acute toxicity. Biotechnology has enabled discovery of more naturally-occurring polyketides and evolution of new polyketides with novel or improved bioactivity.
Aspergillus fumigatus is a species of fungus in the genus Aspergillus, and is one of the most common Aspergillus species to cause disease in individuals with an immunodeficiency.
Citrinin is a mycotoxin which is often found in food. It is a secondary metabolite produced by fungi that contaminates long-stored food and it can cause a variety of toxic effects, including kidney, liver and cell damage. Citrinin is mainly found in stored grains, but sometimes also in fruits and other plant products.
Cyclopiazonic acid (α-CPA), a mycotoxin and a fungal neurotoxin, is made by the molds Aspergillus and Penicillium. It is an indole-tetramic acid that serves as a toxin due to its ability to inhibit calcium-dependent ATPases found in the endoplasmic and sarcoplasmic reticulum. This inhibition disrupts the muscle contraction-relaxation cycle and the calcium gradient that is maintained for proper cellular activity in cells.
Gliotoxin is a sulfur-containing mycotoxin that belongs to a class of naturally occurring 2,5-diketopiperazines produced by several species of fungi, especially those of marine origin. It is the most prominent member of the epipolythiopiperazines, a large class of natural products featuring a diketopiperazine with di- or polysulfide linkage. These highly bioactive compounds have been the subject of numerous studies aimed at new therapeutics. Gliotoxin was originally isolated from Gliocladium fimbriatum, and was named accordingly. It is an epipolythiodioxopiperazine metabolite that is one of the most abundantly produced metabolites in human invasive Aspergillosis (IA).
Polyketide synthases (PKSs) are a family of multi-domain enzymes or enzyme complexes that produce polyketides, a large class of secondary metabolites, in bacteria, fungi, plants, and a few animal lineages. The biosyntheses of polyketides share striking similarities with fatty acid biosynthesis.
Sterigmatocystin is a polyketide mycotoxin produced by certain species of Aspergillus. The toxin is naturally found in some cheeses.
Aspergillus terreus, also known as Aspergillus terrestris, is a fungus (mold) found worldwide in soil. Although thought to be strictly asexual until recently, A. terreus is now known to be capable of sexual reproduction. This saprotrophic fungus is prevalent in warmer climates such as tropical and subtropical regions. Aside from being located in soil, A. terreus has also been found in habitats such as decomposing vegetation and dust. A. terreus is commonly used in industry to produce important organic acids, such as itaconic acid and cis-aconitic acid, as well as enzymes, like xylanase. It was also the initial source for the drug mevinolin (lovastatin), a drug for lowering serum cholesterol.
Monocerin is a dihydroisocoumarin and a polyketide metabolite that originates from various fungal species. It has been shown to display antifungal, plant pathogenic, and insecticidal characteristics. Monocerin has been isolated from Dreschlera monoceras, D. ravenelii, Exserohilum turcicum, and Fusarium larvarum.
Aspergillus ochraceus is a mold species in the genus Aspergillus known to produce the toxin ochratoxin A, one of the most abundant food-contaminating mycotoxins, and citrinin. It also produces the dihydroisocoumarin mellein. It is a filamentous fungus in nature and has characteristic biseriate conidiophores. Traditionally a soil fungus, has now began to adapt to varied ecological niches, like agricultural commodities, farmed animal and marine species. In humans and animals the consumption of this fungus produces chronic neurotoxic, immunosuppressive, genotoxic, carcinogenic and teratogenic effects. Its airborne spores are one of the potential causes of asthma in children and lung diseases in humans. The pig and chicken populations in the farms are the most affected by this fungus and its mycotoxins. Certain fungicides like mancozeb, copper oxychloride, and sulfur have inhibitory effects on the growth of this fungus and its mycotoxin producing capacities.
Phenolic lipids are a class of natural products composed of long aliphatic chains and phenolic rings. Phenolic lipids occur in plants, fungi and bacteria.
Asterric acid is a fungal metabolite that can inhibit endothelin binding, first isolated from Aspergillus terreus. Its derivatives and similar phenolic fungal isolates are a subject of research on anti-angiogenic compounds.
Pseurotin A is a secondary metabolite of Aspergillus.
Atrop-abyssomicin C is a polycyclic polyketide-type natural product that is the atropisomer of abyssomicin C. It is a spirotetronate that belongs to the class of tetronate antibiotics, which includes compounds such as tetronomycin, agglomerin, and chlorothricin. In 2006, the Nicolaou group discovered atrop-abyssomicin C while working on the total synthesis of abyssomicin C. Then in 2007, Süssmuth and co-workers isolated atrop-abyssomicin C from Verrucosispora maris AB-18-032, a marine actinomycete found in sediment of the Japanese sea. They found that atrop-abyssomicin C was the major metabolite produced by this strain, while abyssomicin C was a minor product. The molecule displays antibacterial activity by inhibiting the enzyme PabB, thereby depleting the biosynthesis of p-aminobenzoate.
Dihydromaltophilin, or heat stable anti-fungal factor (HSAF), is a secondary metabolite of Streptomyces sp. and Lysobacter enzymogenes. HSAF is a polycyclic tetramate lactam containing a single tetramic acid unit and a 5,5,6-tricyclic system. HSAF has been shown to have anti-fungal activity mediated through the disruption of the biosynthesis of Sphingolipid's by targeting a ceramide synthase unique to fungi.
Aspergillus viridinutans is a species of fungus in the genus Aspergillus. The species was first isolated in Frankston, Victoria, Australia and described in 1954. It is from the Fumigati section of Aspergillus. Several fungi from this section produce heat-resistant ascospores, and the isolates from this section are frequently obtained from locations where natural fires have previously occurred. A. viridinutans has been identified as the cause of chronic aspergillosis. The mycotoxin viriditoxin was first identified in A. viridinutans. A draft genome sequence of the strain derived from the original species description has been generated.
Tetrahydroxanthones are natural products formally derived by partial reduction of xanthone. They are produced by various fungi, bacteria, and plants. Some are precursors to larger xanthone natural products. One example is neosartorin, composed of 5-acetylblennolide A and blennolide C, exhibits antibacterial activity against Gram-positive bacteria, notably including Staphylococcus aureus.
Cercosporin is a red toxin created by the fungal genus Cercospora.Cercospora act as pathogens on a variety of plants including corn, tobacco, soybean, and coffee. Cercosporin is a perylenequinone natural product that is photoactivated and uses reactive oxygen species (ROS) to damage cell components.
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