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Monocerin
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''. Biosynthesis Polyketide synthases (PKSs) of fungi are Type I PKSs. Monocerin has been confirmed by biosynthesis studies to have heptaketide origins. Monocerin PKS produces an intermediate with initially a high degree of reductive modification but ends with a classical β-polyketide moiety. Dihydroisocoumarin is the first PKS-free intermediate which would be formed from the reduced heptaketide whose assembly pathway is shown in figure 1. Ketosynthase, ketoreductase, dehydrates, enol reductases and cyclisases are shown as domains of the Monocerin PKS and methyl transferase is considered to be a tailoring enzyme. # Formation of an enolate ion on t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dihydroisocoumarin
Dihydroisocoumarins are phenolic compounds related to isocoumarin. Dihydroisocoumarin glucosides can be found in ''Caryocar glabrum ''Caryocar glabrum'' is a species of tree in the family Caryocaraceae. It is native to South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portio ...''. References {{heterocyclic-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ether
In organic chemistry, ethers are a class of compounds that contain an ether group—an oxygen atom connected to two alkyl or aryl groups. They have the general formula , where R and R′ represent the alkyl or aryl groups. Ethers can again be classified into two varieties: if the alkyl or aryl groups are the same on both sides of the oxygen atom, then it is a simple or symmetrical ether, whereas if they are different, the ethers are called mixed or unsymmetrical ethers. A typical example of the first group is the solvent and anaesthetic diethyl ether, commonly referred to simply as "ether" (). Ethers are common in organic chemistry and even more prevalent in biochemistry, as they are common linkages in carbohydrates and lignin. Structure and bonding Ethers feature bent C–O–C linkages. In dimethyl ether, the bond angle is 111° and C–O distances are 141 pm. The barrier to rotation about the C–O bonds is low. The bonding of oxygen in ethers, alcohols, and water is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mycotoxins
A mycotoxin (from the Greek μύκης , "fungus" and τοξίνη , "toxin") is a toxic secondary metabolite produced by organisms of kingdom Fungi and is capable of causing disease and death in both humans and other animals. The term 'mycotoxin' is usually reserved for the toxic chemical products produced by fungi that readily colonize crops. Examples of mycotoxins causing human and animal illness include aflatoxin, citrinin, fumonisins, ochratoxin A, patulin, trichothecenes, zearalenone, and ergot alkaloids such as ergotamine. One mold species may produce many different mycotoxins, and several species may produce the same mycotoxin. Production Most fungi are aerobic (use oxygen) and are found almost everywhere in extremely small quantities due to the diminute size of their spores. They consume organic matter wherever humidity and temperature are sufficient. Where conditions are right, fungi proliferate into colonies and mycotoxin levels become high. The reason for the product ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dihydroisocoumarins
Dihydroisocoumarins are phenolic compounds related to isocoumarin. Dihydroisocoumarin glucosides can be found in ''Caryocar glabrum ''Caryocar glabrum'' is a species of tree in the family Caryocaraceae. It is native to South America. Chemical compounds Dihydroisocoumarin Dihydroisocoumarins are phenolic compounds related to isocoumarin. Dihydroisocoumarin glucosides can ...''. References {{heterocyclic-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Setosphaeria Turcica
''Setosphaeria turcica'' (anamorph ''Exserohilum turcicum''; formerly known as ''Helminthosporium turcicum'') is the causal agent of northern corn leaf blight in maize. It is a serious fungal disease prevalent in cooler climates and tropical highlands wherever corn is grown. It is characterized by large cigar shaped necrotic lesions that develop on the leaves due to the polyketide metabolite monocerin. Races Races of ''S. turcica'' are named for the maize R genes which are not effective against them. For example, the maize gene ''Ht1'' does not confer resistance against a Race 1 isolate, while genes ''Ht2'' and/or ''Ht3'' do. In contrast, genes ''Ht2'' and ''HtN'' do not confer resistance against a Race 2N isolate, while gene ''Ht1'' does. Isolates which do not overcome any known R gene are termed Race 0. Race 1, which overcomes the ''Ht1'' resistance gene, was originally discovered in Hawaii in 1973. By the time it was first noted in the continental United States, in India ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fungicide Use In The United States
This article summarizes different crops, what common fungal problems they have, and how fungicide should be used in order to mitigate damage and crop loss. This page also covers how specific fungal infections affect crops present in the United States. Almonds Alternaria leaf spot Symptoms of Alternaria leaf spot appear as lesions with tan spots on the leaves. The centers of these lesions become black with fungal sporulation. This infection can lead to tree death within 3–4 years of the first serious outbreak. Orchards in high humidity areas result in the largest yield loss, often in excess of 50%. Yield loss tends to rise every year as the tree becomes weaker each year after infection. Three fungicide applications can achieve 60–80% control of leaf spot.Specific Section 18 Emergency Exemption Request to use Azoxystrobin (Abound Flowable) to Control Alternaria on Almonds in San Joaquin Valley of California, California Department of Pesticide Regulation, 1999. Anthracno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cucumber
Cucumber (''Cucumis sativus'') is a widely-cultivated Vine#Horticultural climbing plants, creeping vine plant in the Cucurbitaceae family that bears usually cylindrical Fruit, fruits, which are used as culinary vegetables.Cucumber " ''Encyclopædia Britannica''. [1998] 2019. Considered an annual plant, there are three main varieties of cucumber—slicing, Pickled cucumber, pickling, and Seedless fruit, seedless—within which several cultivars have been created. The cucumber originates from South Asia, but now grows on most continents, as many different types of cucumber are traded on the global market. In North America, the term ''wild cucumber'' refers to plants in the Genus, genera ''Echinocystis'' and ''Marah (plant), Marah'', though the two are not closely related. Description The cucumber is a Vine# ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johnson Grass
Johnson grass or Johnsongrass, ''Sorghum halepense'', is a plant in the grass family, Poaceae, native to Asia and northern Africa. The plant has been introduced to all continents except Antarctica, and most larger islands and archipelagos. It reproduces by rhizomes and seeds. Johnson grass has been used for Fodder, forage and to stop erosion, but it is often considered a weed because: * Foliage that becomes wilted from frost or hot, dry weather can contain sufficient amounts of hydrogen cyanide to kill cattle and horses if it is eaten in quantity. * The foliage can cause 'bloat' in such herbivores from the accumulation of excessive nitrates; otherwise, it is edible. * It grows and spreads rapidly, it can 'choke out' other cash crops planted by farmers. This species occurs in crop fields, pastures, abandoned fields, rights-of-way, forest edges, and along streambanks. It thrives in open, disturbed, rich, bottom ground, particularly in cultivated fields. Johnson grass that is resi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wooly Aphids
Woolly aphids (subfamily: Eriosomatinae) are sap-sucking insects that produce a filamentous waxy white covering which resembles cotton or wool. The adults are winged and move to new locations where they lay egg masses. The nymphs often form large cottony masses on twigs, for protection from predators. Woolly aphids occur throughout the Northern Hemisphere. Many of the numerous species of woolly aphids have only one host plant species, or alternating generations on two specific hosts. They have been known to cause botanical damage and are often considered a pest. While most damage is minor, they can spread plant diseases and fungi. Some species can produce galls as well. In flight they have been described as looking like "flying mice." Other nicknames include "angel flies", “cotton fairies”, "fluff bugs", "fairy flies", "ash bugs", "snow bugs", "fluffer fairies", "poodle flies", and "fluffy gnats". Diet Woolly aphids feed by inserting their needle-like mouthparts into plan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maize
Maize ( ; ''Zea mays'' subsp. ''mays'', from es, maíz after tnq, mahiz), also known as corn (North American and Australian English), is a cereal grain first domesticated by indigenous peoples in southern Mexico about 10,000 years ago. The leafy stalk of the plant produces pollen inflorescences (or "tassels") and separate ovuliferous inflorescences called ears that when fertilized yield kernels or seeds, which are fruits. The term ''maize'' is preferred in formal, scientific, and international usage as a common name because it refers specifically to this one grain, unlike ''corn'', which has a complex variety of meanings that vary by context and geographic region. Maize has become a staple food in many parts of the world, with the total production of maize surpassing that of wheat or rice. In addition to being consumed directly by humans (often in the form of masa), maize is also used for corn ethanol, animal feed and other maize products, such as corn starch and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyketide
Polyketides are a class of natural products derived from a precursor molecule consisting of a chain of alternating ketone (or reduced forms of a ketone) and methylene groups: (-CO-CH2-). 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. History Naturally produced polyketides by various plants and organisms have been used by humans since before studies on them began in the 19th and 20th century. In 1893, J. Norman Collie synthesized detectable amounts of orcinol by heating dehy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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