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Cercosporin
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 (membranes, proteins, lipids, etc). Biosynthesis Light is required for biosynthesis and activation of cercosporin, and it has been demonstrated that light, temperature, and culture medium are regulating factors in the production of cercosporin. Cercosporin is biosynthesized via polyketide synthases, and there are several genes that have been found responsible in the creation of the natural product. Overall, there are 8 CTB enzymes (CTB1-8) that contribute to the production of cercosporin. CTB1 (cercosporin toxin biosynthesis) is a non-reducing PKS consisting of a KS, AT, TE/CYC and 2 ACP domains that are vital in the initiation of the creation of cercosporin. The other CTB ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cercosporin Biosynthesis
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 (membranes, proteins, lipids, etc). Biosynthesis Light is required for biosynthesis and activation of cercosporin, and it has been demonstrated that light, temperature, and culture medium are regulating factors in the production of cercosporin. Cercosporin is biosynthesized via polyketide synthases, and there are several genes that have been found responsible in the creation of the natural product. Overall, there are 8 CTB enzymes (CTB1-8) that contribute to the production of cercosporin. CTB1 (cercosporin toxin biosynthesis) is a non-reducing PKS consisting of a KS, AT, TE/CYC and 2 ACP domains that are vital in the initiation of the creation of cercosporin. The other CTB ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toxin
A toxin is a naturally occurring organic poison produced by metabolic activities of living cells or organisms. Toxins occur especially as a protein or conjugated protein. The term toxin was first used by organic chemist Ludwig Brieger (1849–1919) and is derived from the word toxic. Toxins can be small molecules, peptides, or proteins that are capable of causing disease on contact with or absorption by body tissues interacting with biological macromolecules such as enzymes or cellular receptors. Toxins vary greatly in their toxicity, ranging from usually minor (such as a bee sting) to potentially fatal even at extremely low doses (such as botulinum toxin). Toxins are largely secondary metabolites, which are organic compounds that are not directly involved in an organism's growth, development, or reproduction, instead often aiding it in matters of defense. Terminology Toxins are often distinguished from other chemical agents strictly based on their biological origin. Le ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cercospora
''Cercospora'' is a genus of ascomycete fungi. Most species have no known sexual stage, and when the sexual stage is identified, it is in the genus ''Mycosphaerella''. Most species of this genus cause plant diseases, and form leaf spots. It is a relatively well-studied genus of fungi, but there are countless species not yet described, and there is still much to learn about the best-known of the species. Selected species *''Cercospora acetosella'' - found on sheep sorrel and other docks *'' Cercospora aciculina'' *'' Cercospora agerati'' *''Cercospora alabemensis'' *'' Cercospora alismatis'' *'' Cercospora althaeina'' *''Cercospora angreci'' - causes leaf spot of orchids *'' Cercospora angulata'' *'' Cercospora apii'' - causes leaf spot on celery, and found on other plants, including '' Impatiens'' * ''Cercospora apii'' f.sp. ''clerodendri'' *'' Cercospora apiicola'' - causes leaf spot on celery *'' Cercospora arachidicola'' - causes peanut leaf spot *'' Cercospora arctii'' *' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natural Product
A natural product is a natural compound or substance produced by a living organism—that is, found in nature. In the broadest sense, natural products include any substance produced by life. Natural products can also be prepared by chemical synthesis (both semisynthesis and total synthesis) and have played a central role in the development of the field of organic chemistry by providing challenging synthetic targets. The term natural product has also been extended for commercial purposes to refer to cosmetics, dietary supplements, and foods produced from natural sources without added artificial ingredients. Within the field of organic chemistry, the definition of natural products is usually restricted to organic compounds isolated from natural sources that are produced by the pathways of primary or secondary metabolism. Within the field of medicinal chemistry, the definition is often further restricted to secondary metabolites. Secondary metabolites (or specialized metabolites ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reactive Oxygen Species
In chemistry, reactive oxygen species (ROS) are highly reactive chemicals formed from diatomic oxygen (). Examples of ROS include peroxides, superoxide, hydroxyl radical, singlet oxygen, and alpha-oxygen. The reduction of molecular oxygen () produces superoxide (), which is the precursor to most other reactive oxygen species: :O2 + e^- -> \ ^\bullet O2- Dismutation of superoxide produces hydrogen peroxide (): :2 H+ + \ ^\bullet O2^- + \ ^\bullet O2^- -> H2O2 + O2 Hydrogen peroxide in turn may be partially reduced, thus forming hydroxide ions and hydroxyl radicals (), or fully reduced to water: :H2O2 + e^- -> HO^- + \ ^\bullet OH :2 H+ + 2 e- + H2O2 -> 2 H2O In a biological context, ROS are byproducts of the normal metabolism of oxygen. ROS have roles in cell signaling and homeostasis. ROS are intrinsic to cellular functioning, and are present at low and stationary levels in normal cells. In plants, ROS are involved in metabolic processes related to photoprotection and toleran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetal
In organic chemistry, an acetal is a functional group with the connectivity . Here, the R groups can be organic fragments (a carbon atom, with arbitrary other atoms attached to that) or hydrogen, while the R' groups must be organic fragments not hydrogen. The two R' groups can be equivalent to each other (a "symmetric acetal") or not (a "mixed acetal"). Acetals are formed from and convertible to aldehydes or ketones and have the same oxidation state at the central carbon, but have substantially different chemical stability and reactivity as compared to the analogous carbonyl compounds. The central carbon atom has four bonds to it, and is therefore saturated and has tetrahedral geometry. The term ketal is sometimes used to identify structures associated with ketones (both R groups organic fragments rather than hydrogen) rather than aldehydes and, historically, the term acetal was used specifically for the aldehyde-related cases (having at least one hydrogen in place of an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perylene
Perylene or perilene is a polycyclic aromatic hydrocarbon with the chemical formula C20H12, occurring as a brown solid. It or its derivatives may be carcinogenic, and it is considered to be a hazardous pollutant. In cell membrane cytochemistry, perylene is used as a fluorescent lipid probe. It is the parent compound of a class of rylene dyes. Reactions Like other polycyclic aromatic compounds, perylene is reduced by alkali metals to give a deeply colored radical anion and a dianion. The diglyme solvates of these salts have been characterized by X-ray crystallography. Emission Perylene displays blue fluorescence. It is used as a blue-emitting dopant material in OLEDs, either pure or substituted. Perylene can be also used as an organic photoconductor. It has an absorption maximum at 434 nm, and as with all polycyclic aromatic compounds, low water solubility (1.2 x 10−5 mmol/L). Perylene has a molar absorptivity of 38,500 M−1cm−1 at 435.7 nm. Image:Perylene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atropisomer
Atropisomers are stereoisomers arising because of hindered rotation about a single bond, where energy differences due to steric strain or other contributors create a barrier to rotation that is high enough to allow for isolation of individual conformers. They occur naturally and are important in pharmaceutical design. When the substituents are achiral, these conformers are enantiomers (''atropoenantiomers''), showing axial chirality; otherwise they are diastereomers (''atropodiastereomers''). Etymology and history The word ''atropisomer'' ( el, άτροπος, , meaning "without turn") was coined in application to a theoretical concept by German biochemist Richard Kuhn for Karl Freudenberg's seminal ''Stereochemie'' volume in 1933. Atropisomerism was first experimentally detected in a tetra substituted biphenyl, a diacid, by George Christie and James Kenner in 1922. Michinori Ōki further refined the definition of atropisomers taking into account the temperature-dependence asso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterocyclic Compounds With 6 Rings
A heterocyclic compound or ring structure is a cyclic compound that has atoms of at least two different elements as members of its ring(s). Heterocyclic chemistry is the branch of organic chemistry dealing with the synthesis, properties, and applications of these heterocycles. Examples of heterocyclic compounds include all of the nucleic acids, the majority of drugs, most biomass (cellulose and related materials), and many natural and synthetic dyes. More than half of known compounds are heterocycles. 59% of US FDA-approved drugs contain nitrogen heterocycles. Classification The study of heterocyclic chemistry focuses especially on unsaturated derivatives, and the preponderance of work and applications involves unstrained 5- and 6-membered rings. Included are pyridine, thiophene, pyrrole, and furan. Another large class of heterocycles refers to those fused to benzene rings. For example, the fused benzene derivatives of pyridine, thiophene, pyrrole, and furan are quinol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxygen Heterocycles
Oxygen is the chemical element with the chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen Group (periodic table), group in the periodic table, a highly Chemical reaction, reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as well as with other chemical compound, compounds. Oxygen is Earth's Abundance of the chemical elements, most abundant element, and after hydrogen and helium, it is the third-most abundant element in the universe. At standard temperature and pressure, two atoms of the element chemical bond, bind to form Allotropes of oxygen#Dioxygen, dioxygen, a colorless and odorless diatomic molecule, diatomic gas with the formula . Diatomic oxygen gas currently constitutes 20.95% of the Earth's atmosphere, though this has Geological history of oxygen, changed considerably over long periods of time. Oxygen makes up almost half of the Earth's crust in the form of oxides.Atkins, P.; Jones, L.; Laverman, L. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
