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2-NBDG
2-NBDG is a fluorescent tracer used for monitoring glucose uptake into living cells; it consists of a glucosamine molecule substituted with a 7-nitrobenzofurazan fluorophore at its amine group. It is widely referred to a fluorescent derivative of glucose, and it is used in cell biology to visualize uptake of glucose by cells. Cells that have taken up the compound fluoresce green. 2-NBDG is similar to radiolabeled glucose in that both can be used to detect glucose transport. Unlike radiolabeled glucose, 2-NBDG is compatible with fluorescence techniques such as a fluorescent microscopy, flow cytometry, and fluorimetry The compound is taken up by a variety of mammalian, plant, and microbial cells In mammalian cells, one transporter for 2-NBDG is supposed to be GLUT2., but this has been recently challenged (see below). In bacterial cells, the predominant transporter is the mannose phosphotransferase system. Cells that lack these or other compatible transporters do not tak ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorescence In The Life Sciences
Fluorescence is used in the life sciences generally as a non-destructive way of tracking or analysing biological molecules. Some proteins or small molecules in cells are naturally fluorescent, which is called intrinsic fluorescence or autofluorescence (such as NADH, tryptophan or endogenous chlorophyll, phycoerythrin or green fluorescent protein). Alternatively, specific or general proteins, nucleic acids, lipids or small molecules can be "labelled" with an extrinsic fluorophore, a fluorescent dye which can be a small molecule, protein or quantum dot. Several techniques exist to exploit additional properties of fluorophores, such as fluorescence resonance energy transfer, where the energy is passed non-radiatively to a particular neighbouring dye, allowing proximity or protein activation to be detected; another is the change in properties, such as intensity, of certain dyes depending on their environment allowing their use in structural studies. Fluorescence The principl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammalian
Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or hair, and three middle ear bones. These characteristics distinguish them from reptiles (including birds) from which they diverged in the Carboniferous, over 300 million years ago. Around 6,400 extant species of mammals have been described divided into 29 orders. The largest orders, in terms of number of species, are the rodents, bats, and Eulipotyphla (hedgehogs, moles, shrews, and others). The next three are the Primates (including humans, apes, monkeys, and others), the Artiodactyla ( cetaceans and even-toed ungulates), and the Carnivora (cats, dogs, seals, and others). In terms of cladistics, which reflects evolutionary history, mammals are the only living members of the Synapsida (synapsids); this clade, together w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexosamines
Hexosamines are amino sugars created by adding an amine group to a hexose. Examples include: * Fructosamine (based upon fructose) * Galactosamine (based upon galactose) * Glucosamine (based upon glucose) * Mannosamine (based upon mannose Mannose is a sugar monomer of the aldohexose series of carbohydrates. It is a C-2 epimer of glucose. Mannose is important in human metabolism, especially in the glycosylation of certain proteins. Several congenital disorders of glycosylat ...) External links * * {{organic-compound-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Escherichia Coli
''Escherichia coli'' (),Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. also known as ''E. coli'' (), is a Gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus '' Escherichia'' that is commonly found in the lower intestine of warm-blooded organisms. Most ''E. coli'' strains are harmless, but some serotypes ( EPEC, ETEC etc.) can cause serious food poisoning in their hosts, and are occasionally responsible for food contamination incidents that prompt product recalls. Most strains do not cause disease in humans and are part of the normal microbiota of the gut; such strains are harmless or even beneficial to humans (although these strains tend to be less studied than the pathogenic ones). For example, some strains of ''E. coli'' benefit their hosts by producing vitamin K2 or by preventing the colonization of the intestine by pathogenic bacteria. These mutually beneficial relationships between ''E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Michaelis–Menten Kinetics
In biochemistry, Michaelis–Menten kinetics is one of the best-known models of enzyme kinetics. It is named after German biochemist Leonor Michaelis and Canadian physician Maud Menten. The model takes the form of an equation describing the rate of enzymatic reactions, by relating reaction rate v (rate of formation of product, ce P/math>) to ce S/math>, the concentration of a substrate ''S''. Its formula is given by : v = \frac = V_\max \frac This equation is called the Michaelis–Menten equation. Here, V_\max represents the maximum rate achieved by the system, happening at saturating substrate concentration for a given enzyme concentration. When the value of the Michaelis constant K_\mathrm is numerically equal to the substrate concentration, then the reaction rate is half of V_\max. Biochemical reactions involving a single substrate are often assumed to follow Michaelis–Menten kinetics, without regard to the model's underlying assumptions. Model In 1901, Fren ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphotransferase System
PEP group translocation, also known as the phosphotransferase system or PTS, is a distinct method used by bacteria for sugar uptake where the source of energy is from phosphoenolpyruvate (PEP). It is known to be a multicomponent system that always involves enzymes of the plasma membrane and those in the cytoplasm. The PTS system uses active transport. After the translocation across the membrane, the metabolites transported are modified. The system was discovered by Saul Roseman in 1964. The bacterial phosphoenolpyruvate:sugar phosphotransferase system (PTS) transports and phosphorylates its sugar substrates in a single energy-coupled step. This transport process is dependent on several cytoplasmic phosphoryl transfer proteins - Enzyme I (I), HPr, Enzyme IIA (IIA), and Enzyme IIB (IIB)) as well as the integral membrane sugar permease (IIC).The PTS Enzyme II complexes are derived from independently evolving 4 PTS Enzyme II complex superfamilies, that include the (1) Glucose (Glc),(2) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mannose
Mannose is a sugar monomer of the aldohexose series of carbohydrates. It is a C-2 epimer of glucose. Mannose is important in human metabolism, especially in the glycosylation of certain proteins. Several congenital disorders of glycosylation are associated with mutations in enzymes involved in mannose metabolism. Mannose is not an essential nutrient; it can be produced in the human body from glucose, or converted into glucose. Mannose provides 2–5 kcal/g. It is partially excreted in the urine. Etymology The root of both "mannose" and "mannitol" is manna, which the Bible describes as the food supplied to the Israelites during their journey in the region of Sinai. Several trees and shrubs can produce a substance called manna, such as the "manna tree" ('' Fraxinus ornus'') from whose secretions mannitol was originally isolated. Structure Mannose commonly exists as two different-sized rings, the pyranose (six-membered) form and the furanose (five-membered) form. E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GLUT2
Glucose transporter 2 (GLUT2) also known as solute carrier family 2 (facilitated glucose transporter), member 2 (SLC2A2) is a transmembrane carrier protein that enables protein facilitated glucose movement across cell membranes. It is the principal transporter for transfer of glucose between liver and blood Unlike GLUT4, it does not rely on insulin for facilitated diffusion. In humans, this protein is encoded by the ''SLC2A2'' gene. Tissue distribution GLUT2 is found in cellular membranes of: * liver (Primary) * pancreatic β cell (Primary in mice, tertiary in humans after GLUT1 and GLUT3) * hypothalamus (Not overly significant) * basolateral membrane of small intestine and apical GLUT2 is also suggested. * basolateral membrane of renal tubular cells Function GLUT2 has high capacity for glucose but low affinity (high ''K''M, ca. 15–20 mM) and thus functions as part of the "glucose sensor" in the pancreatic β-cells of rodents, though in human β-cells the role o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microbial
A microorganism, or microbe,, ''mikros'', "small") and ''organism'' from the el, ὀργανισμός, ''organismós'', "organism"). It is usually written as a single word but is sometimes hyphenated (''micro-organism''), especially in older texts. The informal synonym ''microbe'' () comes from μικρός, mikrós, "small" and βίος, bíos, "life". is an organism of microscopic size, which may exist in its single-celled form or as a colony of cells. The possible existence of unseen microbial life was suspected from ancient times, such as in Jain scriptures from sixth century BC India. The scientific study of microorganisms began with their observation under the microscope in the 1670s by Anton van Leeuwenhoek. In the 1850s, Louis Pasteur found that microorganisms caused food spoilage, debunking the theory of spontaneous generation. In the 1880s, Robert Koch discovered that microorganisms caused the diseases tuberculosis, cholera, diphtheria, and anthrax. Because ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plant
Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclude the fungi and some algae, as well as the prokaryotes (the archaea and bacteria). By one definition, plants form the clade Viridiplantae (Latin name for "green plants") which is sister of the Glaucophyta, and consists of the green algae and Embryophyta (land plants). The latter includes the flowering plants, conifers and other gymnosperms, ferns and their allies, hornworts, liverworts, and mosses. Most plants are multicellular organisms. Green plants obtain most of their energy from sunlight via photosynthesis by primary chloroplasts that are derived from endosymbiosis with cyanobacteria. Their chloroplasts contain chlorophylls a and b, which gives them their green color. Some plants are parasitic or mycotrophic and hav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorimetry
Fluorescence spectroscopy (also known as fluorimetry or spectrofluorometry) is a type of electromagnetic spectroscopy that analyzes fluorescence from a sample. It involves using a beam of light, usually ultraviolet light, that excites the electrons in molecules of certain compounds and causes them to emit light; typically, but not necessarily, visible light. A complementary technique is absorption spectroscopy. In the special case of single molecule fluorescence spectroscopy, intensity fluctuations from the emitted light are measured from either single fluorophores, or pairs of fluorophores. Devices that measure fluorescence are called fluorometers. Theory Molecules have various states referred to as energy levels. Fluorescence spectroscopy is primarily concerned with electronic and vibrational states. Generally, the species being examined has a ground electronic state (a low energy state) of interest, and an excited electronic state of higher energy. Within each of these elec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glucosamine
Glucosamine (C6H13NO5) is an amino sugar and a prominent precursor in the biochemical synthesis of glycosylated proteins and lipids. Glucosamine is part of the structure of two polysaccharides, chitosan and chitin. Glucosamine is one of the most abundant monosaccharides. Produced commercially by the hydrolysis of shellfish exoskeletons or, less commonly, by fermentation of a grain such as corn or wheat, glucosamine has many names depending on country. Although a common dietary supplement, there is little evidence that it is effective for relief of arthritis or pain, and is not an approved prescription drug. Dietary supplement Oral glucosamine is a dietary supplement and is not a prescription drug. Glucosamine is marketed as a supplement to support the structure and function of joints, and the marketing is targeted to people with osteoarthritis. Commonly sold forms of glucosamine are glucosamine sulfate, glucosamine chondroitin, glucosamine hydrochloride, and ''N''-acetylgluco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
