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Geosmin
Geosmin ( ) is an irregular sesquiterpenoid with a distinct earthy or musty odor, which most people can easily smell. The geosmin odor detection threshold in humans is very low, ranging from 0.006 to 0.01 micrograms per liter in water. Geosmin, along with the irregular monoterpene 2-methylisoborneol, together account for the majority of biologically-caused taste and odor outbreaks in drinking water worldwide and in Fish farming, farmed fish. Geosmin is also responsible for the earthy taste of beetroots and a contributor to the strong scent, known as petrichor, that occurs when rain falls after a spell of dry weather or when soil is disturbed. In chemical terms, geosmin is a bicyclic molecule, bicyclic alcohol (chemistry), alcohol with chemical formula, formula , a derivative of decalin. It is produced from the universal sesquiterpene precursor farnesyl pyrophosphate (also known as farnesyl diphosphate), in a two-step -dependent reaction. Its name is derived from the Ancient Greek ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geosmin Synthase
Geosmin synthase or germacradienol-geosmin synthase designates a class of bifunctional enzymes () that catalyze the conversion of farnesyl diphosphate (FPP) to geosmin, a volatile organic compound, volatile organic compound known for its earthy smell. The N-terminal half of the protein catalyzes the conversion of farnesyl diphosphate to germacradienol and germacrene D, followed by the C-terminal-mediated conversion of germacradienol to geosmin. The conversion of FPP to geosmin was previously thought to involve multiple enzymes in a biosynthetic pathway. Species distribution Geosmin is found in a wide variety of microbes such as cyanobacteria and Actinomycetota, actinobacteria. Geosmin has also been found in myxobacteria, fungi, arthropods, and plants such as beets. Based on studies performed on a geosmin synthase (encoded by SCO6073) in Streptomyces coelicolor, ''Streptomyces coelicor'' and the high sequence similarity between this and other known or putative geosmin synthases ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2-methylisoborneol
2-Methylisoborneol (MIB) is an irregular monoterpene derived from the universal monoterpene precursor geranyl pyrophosphate. MIB and the irregular sesquiterpene geosmin together account for the majority of biologically-caused taste and odor outbreaks in drinking water worldwide. MIB has a distinct earthy or musty odor, which most people can easily smell. The odor detection threshold of MIB is very low, ranging from 0.002 to 0.02 micrograms per liter in water. MIB is also a factor in cork taint in winemaking. MIB is produced by various blue-green algae (cyanobacteria) and filamentous bacteria in the class Actinomycetia, and also some other prokaryotes and eukaryotes. The main genera in the cyanobacteria that have been shown to produce MIB include ''Oscillatoria'', ''Phormidium'', and ''Planktothrix'', while the main genus in the Actinomycetia that produces MIB is ''Streptomyces''. They give a musty or earthy odor that can be quite strong if an algal bloom is present. Subsequent de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sesquiterpenoid
Sesquiterpenes are a class of terpenes that consist of three isoprene units and often have the molecular formula C15H24. Like monoterpenes, sesquiterpenes may be cyclic or contain rings, including many combinations. Biochemical modifications such as oxidation or rearrangement produce the related sesquiterpenoids. It is estimated (2006) that 3000 sesquiterpenes have been identified. Biosynthesis and examples The reaction of geranyl pyrophosphate with isopentenyl pyrophosphate results in the 15-carbon farnesyl pyrophosphate (FPP), which is an intermediate in the biosynthesis of sesquiterpenes such as farnesene. Cyclic sesquiterpenes are more common than cyclic monoterpenes because of the increased chain length and additional double bond in the sesquiterpene precursors. In addition to common six-membered ring systems such as the ones found in zingiberene and bisacurone, cyclization of one end of the chain to the other end can lead to macrocyclic rings such as humulene. Lon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Odor Detection Threshold
The odor detection threshold is the lowest concentration of a certain odor compound that is perceivable by the human sense of smell. The threshold of a chemical compound is determined in part by its shape, polarity, partial charges, and molecular mass. The olfactory mechanisms responsible for a compound's different detection threshold is not well understood. As such, odor thresholds cannot be accurately predicted. Rather, they must be measured through extensive tests using human subjects in laboratory settings. Optical isomers can have different detection thresholds because their conformations may cause them to be less perceivable for the human nose. It is only in recent years that such compounds were separated on gas chromatographs. For raw water treatment and waste water management, the term commonly used is Threshold Odor Number (TON). For instance, the water to be supplied for domestic use in Illinois is 3 TON. Values * The threshold value is the concentration at whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Petrichor
Petrichor ( ) is the earthy scent produced when rain falls on dry soil. The word was coined by Isabel Joy Bear and Richard Grenfell Thomas , the ethereal fluid that is the blood of the gods in Greek mythology. Origins A brief note on the phenomenon by (1833–1908) appeared in ''The Chemical News'' on 17 April 1891 and was re-published in its entirety, a month later, in '' The Scientific American'', in which he wrote, "This subject, with which I was occupied more than twenty-five years ago, appears from a paragraph in the last number of the ''Chemical News'' to have recently attracted the attention of Professor Berthelot and onsieur G.Andre." Phipson was referring to a short paper read by Berthelot and André at the meeting of the French Académie des Sciences on 23 April 1891, and printed in Volume 112 (1891) of ''Comptes Rendus'', entitled "Sur l'odeur propre de la terre" ("On the earth's own smell"). Phipson continues, "I find, on referring to my old notes, which are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Streptomyces
''Streptomyces'', from στρεπτός (''streptós''), meaning "twisted", and μύκης (''múkés''), meaning "fungus", is the largest genus of Actinomycetota, and the type genus of the family Streptomycetaceae. Over 700 species of ''Streptomyces'' bacteria have been described. As with the other Actinomycetota, streptomycetes are gram-positive, and have very large genomes with high GC content. Found predominantly in soil and decaying vegetation, most streptomycetes produce spores, and are noted for their distinct "earthy" odor that results from production of a volatile metabolite, geosmin. Different strains of the same species may colonize very diverse environments. Streptomycetes are characterised by a complex secondary metabolism. Between 5-23% (average: 12%) of the protein-coding genes of each ''Streptomyces'' species are implicated in secondary metabolism. Streptomycetes produce over two-thirds of the clinically useful antibiotics of natural origin (e.g., neomy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Farnesyl Diphosphate
Farnesyl pyrophosphate (FPP), also known as farnesyl diphosphate (FDP), is the precursor to all sesquiterpenes, which comprises thousands of compounds. These include all sesquiterpenes as well as sterols and carotenoids. It is also used in the synthesis of CoQ (part of the electron transport chain), as well as dehydrodolichol diphosphate (a precursor of dolichol, which transports proteins to the ER lumen for ''N''-glycosylation). Biosynthesis Farnesyl pyrophosphate synthase (a prenyl transferase) catalyzes sequential condensation reactions of dimethylallyl pyrophosphate with 2 units of 3-isopentenyl pyrophosphate to form farnesyl pyrophosphate: : Pharmacology The above reactions are inhibited by bisphosphonates (used for osteoporosis). Farnesyl pyrophosphate is a selective agonist of TRPV3. Related compounds * Farnesene * Farnesol * Geranyl pyrophosphate *Geranylgeranyl pyrophosphate Geranylgeranyl pyrophosphate is an intermediate in the biosynthesis of diterpenes and d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nature Chemical Biology
''Nature Chemical Biology'' is a monthly peer-reviewed scientific journal published by Nature Portfolio. It was established in June 2005 by founding Chief Editor Terry L. Sheppard as part of Nature Publishing Group. Sheppard was the Chief Editor of the journal 2004–2022. The current editor-in-chief is Russell Johnson. Aims and scope The publishing focus of ''Nature Chemical Biology'' is a forum for original research and commentary in chemical biology. Published topics encompass concepts and research methods in chemistry, biology, and related disciplines with the result of controlling biological systems at the molecular level. Authors (contributors) are chemical biologists, also chemists involved in interdisciplinary research between chemistry and biology, along with biologists who produce research results in understanding and controlling biological processes at the molecular level. Interdisciplinary research in chemistry and biology is emphasized. The journal's main focus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journal Of The American Chemical Society
The ''Journal of the American Chemical Society'' (also known as JACS) is a weekly peer-reviewed scientific journal that was established in 1879 by the American Chemical Society. The journal has absorbed two other publications in its history, the ''Journal of Analytical and Applied Chemistry'' (July 1893) and the ''American Chemical Journal'' (January 1914). It covers all fields of chemistry. Since 2021, the editor-in-chief is Erick M. Carreira (ETH Zurich). In 2014, the journal moved to a hybrid open access publishing model. Abstracting and indexing The journal is abstracted and indexed in: According to the ''Journal Citation Reports'', the journal has a 2023 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a type of journal ranking. Journals with higher impact factor values are considered more prestigious or important within their field. The Impact Factor of a journa ... of 14.4. Editors-in-chief The following people are or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Planktothrix
''Planktothrix'' is a diverse genus of filamentous cyanobacteria observed to amass in algal blooms in water ecosystems across the globe. Like all Oscillatoriales, ''Planktothrix'' species have no heterocyst, heterocysts and no akinetes. ''Planktothrix'' are unique because they have Trichome#Algal trichomes, trichomes and contain gas vacuoles unlike typical planktonic organisms. Previously, some species of the taxon were grouped within the genus ''Oscillatoria'', but recent work has defined ''Planktothrix'' as its own genus. A tremendous body of work on ''Planktothrix'' ecology and physiology has been done by A.E. Walsby, Anthony E. Walsby, and the 55.6 kb microcystin synthetase gene which gives these organisms the ability to synthesize toxins has been sequenced. ''P. agardhii'' is an example of a Holotype, type species of the genus. ''P. agardhii'' and ''P. rubescens'' are commonly observed in lakes of the Northern Hemisphere where they are known producers of potent hepatotoxins ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Streptomyces Coelicolor
''Streptomyces albidoflavus'' is a bacterium species from the genus of ''Streptomyces'' which has been isolated from soil from Poland. ''Streptomyces albidoflavus'' produces dibutyl phthalate and streptothricins. Small noncoding RNA Bacterial small RNAs are involved in post-transcriptional regulation. Using deep sequencing ''S. albidoflavus'' transcriptome was analysed at the end of exponential growth. 63 small RNAs were identified. Expression of 11 of them was confirmed by Northern blot. The sRNAs were shown to be only present in ''Streptomyces'' species. sRNA scr4677 (''Streptomyces coelicolor'' sRNA 4677) is located in the intergenic region between anti-sigma factor ''SCO4677'' gene and a putative regulatory protein gene ''SCO4676''. ''scr4677'' expression requires the ''SCO4677'' activity and ''scr4677'' sRNA itself seem to affect the levels of the ''SCO4676''-associated transcripts. Targets of two of ''S. albidoflavus'' noncoding RNAs have been identified. Noncoding ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biosynthesis
Biosynthesis, i.e., chemical synthesis occurring in biological contexts, is a term most often referring to multi-step, enzyme-Catalysis, catalyzed processes where chemical substances absorbed as nutrients (or previously converted through biosynthesis) serve as enzyme substrate (chemistry), substrates, with conversion by the living organism either into simpler or more complex Product (chemistry), products. Examples of biosynthetic pathways include those for the production of amino acids, lipid membrane components, and nucleotides, but also for the production of all classes of biological macromolecules, and of acetyl-coenzyme A, adenosine triphosphate, nicotinamide adenine dinucleotide and other key intermediate and transactional molecules needed for metabolism. Thus, in biosynthesis, any of an array of Chemical compound, compounds, from simple to complex, are converted into other compounds, and so it includes both the catabolism and anabolism (building up and breaking down) of comple ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
