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Aesculin
Aesculin, also called æsculin or esculin, is a coumarin glucoside that naturally occurs in the trees horse chestnut (''Aesculus hippocastanum''), California buckeye (''Aesculus californica''), prickly box (''Bursaria spinosa''), and daphnin (the dark green resin of '' Daphne mezereum''). It is also found in dandelion coffee. Medical uses As medication, aesculin is sometimes used as a vasoprotective agent. Aesculin is also used in a microbiology laboratory to aid in the identification of bacterial species (especially ''Enterococci'' and ListeriaQadri, S. M., Smith, J. C., Zubairi, S., & DeSilva, M. I. (1981). Esculin hydrolysis by Gram positive bacteria. A rapid test and it's comparison with other methods. Medical microbiology and immunology, 169(2), 67–74. https://doi.org/10.1007/BF02171773 . PMID 6783825). In fact, all strains of Group D Streptococci hydrolyze æsculin in 40% bile. Aesculin hydrolysis test Aesculin is incorporated into agar with ferric citrate and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aesculetin
Aesculetin (also known as esculetin, 6,7-dihydroxycoumarin and cichorigenin) is a derivative of coumarin. It is a natural lactone that derives from the intramolecular cyclization of a cinnamic acid derivative. It is present in chicory and in many toxic and medicinal plants, in form of glycosides and caffeic acid conjugates. This compound is used in some sunscreens, but there is evidence that it acts as a photosensitizer for DNA damage. The sodium salt of its methyl-derivative is used in dermatology for the treatment of varicose veins. It is a blue fluorescence compound found in plants. Aesculin, the glucoside of aesculetin, will fluoresce under long wave ultraviolet light (360 nm). The hydrolysis of aesculin results in loss of this fluorescence. Aesculetin has the ability to quench the inner fluorescence of bovine serum albumin. Aesculetin can be transformed into scopoletin (7-hydroxy-6-methoxycoumarin) and isoscopoletin (6-hydroxy-7-methoxycoumarin) through incubation wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bile Aesculin Agar
Bile Esculin Agar (BEA) is a selective differential agar used to isolate and identify members of the genus ''Enterococcus'', formerly part of the "group D streptococci" (enterococci were reclassified in their own genus in 1984). Composition and process Bile salts are the selective ingredient, while esculin is the differential component. ''Enterococcus'' hydrolyze esculin to products that react with ferric citrate in the medium to produce insoluble iron salts, resulting in the blackening of the medium. Test results must be interpreted in conjunction with gram stain morphology. Uses Bile Esculin Agar is used primarily to differentiate ''Enterococcus'' from ''Streptococcus''. Members of the genus ''Enterococcus'' are capable of growing in the presence of 40% bile (oxgall) and hydrolyzing esculin to glucose and esculetin. Esculetin combines with ferric ions to produce a black complex. For some purposes, certain bacteria are able to hydrolyze aesculin. A plate containing aesculin wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aescin
Aescin or escin is a mixture of saponins with anti-inflammatory, vasoconstrictor and vasoprotective effects found in ''Aesculus hippocastanum'' (the horse chestnut). Aescin is the main active component in horse chestnut, and is responsible for most of its medicinal properties. The main active compound of aescin is β-aescin, although the mixture also contains various other components including α-aescin, protoescigenin, barringtogenol, cryptoescin and benzopyrones. Evidence suggests that aescin, especially pure β-aescin, is a safe and effective treatment for short-term treatment of chronic venous insufficiency; however, more high quality randomized controlled trials are required to confirm the effectiveness. Horse chestnut extract may be as effective and well tolerated as the use of compression stockings. Mechanism of action Aescin appears to produce effects through a wide range of mechanisms. It induces endothelial nitric oxide synthesis by making endothelial cells more pe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glucoside
A glucoside is a glycoside that is derived from glucose. Glucosides are common in plants, but rare in animals. Glucose is produced when a glucoside is hydrolysed by purely chemical means, or decomposed by fermentation or enzymes. The name was originally given to plant products of this nature, in which the other part of the molecule was, in the greater number of cases, an aromatic aldehydic or phenolic compound (exceptions are Jinigrin and Jalapin or Scammonin). It has now been extended to include synthetic ethers, such as those obtained by acting on alcoholic glucose solutions with hydrochloric acid, and also the polysaccharoses, e.g. cane sugar, which appear to be ethers also. Although glucose is the most common sugar present in glucosides, many are known which yield rhamnose or iso-dulcite; these may be termed pentosides. Much attention has been given to the non-sugar parts (aglyca) of the molecules; the constitutions of many have been determined, and the compounds synthe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horse-chestnut (tree)
The genus ''Aesculus'' ( or ), with species called buckeye and horse chestnut, comprises 13–19 species of flowering plants in the family Sapindaceae. They are trees and shrubs native to the temperate Northern Hemisphere, with six species native to North America and seven to 13 species native to Eurasia. Several hybrids occur. ''Aesculus'' exhibits a classical Arcto-Tertiary distribution. Mexican buckeye seedpods resemble the ''Aesculus'' seedpods, but belong to a different genus. Carl Linnaeus named the genus ''Aesculus'' after the Roman name for an edible acorn. Common names for these trees include "buckeye" and "horse chestnut", though they are not in the same order as the true chestnuts, ''Castanea'' in the Fagales. Some are also called white chestnut or red chestnut. In Britain, they are sometimes called conker trees because of their link with the game of conkers, played with the seeds, also called conkers. Description ''Aesculus'' species have stout shoots with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
California Buckeye
''Aesculus californica'', commonly known as the California buckeye or California horse-chestnut, is a species of buckeye native to California and southwestern Oregon. Description It is a large deciduous shrub or small tree, up to tall, with gray bark often coated with lichens and mosses. It typically is multi-trunked, with a crown as broad as it is high. Trees are long lived, with an estimated lifespan between 250–280 (300 maximum) years. The leaves are dark green, palmately compound with five (rarely seven) leaflets. Each leaflet is long, with a finely toothed margin and (particularly in spring) downy surfaces. The leaves are tender and prone to damage from both spring freezing or snow and summer heat and desiccation. The flowers are sweet-scented, white to pale pink, borne on erect panicles long and broad. The fruit is a fig-shaped capsule long, containing a large, round, orange-brown seed, measuring . The seeds are poisonous and are the largest known of any t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prickly Box
''Bursaria spinosa'' is a small tree or shrub in the family Pittosporaceae. The species occurs mainly in the eastern and southern half of Australia and not in Western Australia and the Northern Territory. Reaching 10 m (35 ft) high, it bears fragrant white flowers at any time of year but particularly in summer. A common understorey shrub of eucalyptus woodland, it colonises disturbed areas and fallow farmland. It is an important food plant for several species of butterflies and moths, particularly those of the genus '' Paralucia'', and native bees. Description ''Bursaria spinosa'' has a variable habit, and can grow anywhere from 1 to 12 m high. The dark grey bark is furrowed. The smooth branches are sometimes armed with thorns, and the leaves are arranged alternately along the stems or clustered around the nodes and have a pine-like fragrance when bruised. Linear to oval or wedge-shaped (ovate, obovate or cuneate), they are 2–4.3 cm long and 0.3–1.2 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanometre
330px, Different lengths as in respect to the molecular scale. The nanometre (international spelling as used by the International Bureau of Weights and Measures; SI symbol: nm) or nanometer (American and British English spelling differences#-re, -er, American spelling) is a units of measurement, unit of length in the International System of Units (SI), equal to one billionth (short scale) of a metre () and to 1000 picometres. One nanometre can be expressed in scientific notation as , and as metres. History The nanometre was formerly known as the millimicrometre – or, more commonly, the millimicron for short – since it is of a micron (micrometre), and was often denoted by the symbol mμ or (more rarely and confusingly, since it logically should refer to a ''millionth'' of a micron) as μμ. Etymology The name combines the SI prefix ''nano-'' (from the Ancient Greek , ', "dwarf") with the parent unit name ''metre'' (from Greek , ', "unit of measurement") ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultraviolet
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight, and constitutes about 10% of the total electromagnetic radiation output from the Sun. It is also produced by electric arcs and specialized lights, such as mercury-vapor lamps, tanning lamps, and black lights. Although long-wavelength ultraviolet is not considered an ionizing radiation because its photons lack the energy to ionize atoms, it can cause chemical reactions and causes many substances to glow or fluoresce. Consequently, the chemical and biological effects of UV are greater than simple heating effects, and many practical applications of UV radiation derive from its interactions with organic molecules. Short-wave ultraviolet light damages DNA and sterilizes surfaces with which it comes into contact. F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorescence
Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence. In most cases, the emitted light has a longer wavelength, and therefore a lower photon energy, than the absorbed radiation. A perceptible example of fluorescence occurs when the absorbed radiation is in the ultraviolet region of the electromagnetic spectrum (invisible to the human eye), while the emitted light is in the visible region; this gives the fluorescent substance a distinct color that can only be seen when the substance has been exposed to UV light. Fluorescent materials cease to glow nearly immediately when the radiation source stops, unlike phosphorescent materials, which continue to emit light for some time after. Fluorescence has many practical applications, including mineralogy, gemology, medicine, chemical sensors (fluorescence spectroscopy), fluorescent labelling, dyes, biological detectors, cosmic-ray detection, vac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leuconostoc
''Leuconostoc'' is a genus of gram-positive bacteria, placed within the family of Lactobacillaceae. They are generally ovoid cocci often forming chains. ''Leuconostoc'' spp. are intrinsically resistant to vancomycin and are catalase-negative (which distinguishes them from staphylococci). All species within this genus are heterofermentative and are able to produce dextran from sucrose. They are generally slime-forming. Blamed for causing the 'stink' when creating a sourdough starter, some species are also capable of causing human infection. Because they are an uncommon cause of disease in humans, standard commercial identification kits are often unable to identify the organism. ''Leuconostoc'' spp., along with other lactic acid bacteria such as ''Pediococcus'' and ''Lactobacillus'', are responsible for the fermentation of cabbage, making it sauerkraut. In this process, fresh cabbage is fermented in a light brine, where the sugars in the cabbage are transformed by lactoferment ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
