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Glucose Metabolism Pathway

Connections Of Carbohydrate, Protein, And Lipid Metabolic Pathways

Connections Of Carbohydrate, Protein, And Lipid Metabolic Pathways

Connecting Other Sugars to Glucose Metabolism Sugars, such as galactose, fructose, and glycogen, are catabolized into new products in order to enter the glycolytic pathway. Learning Objectives Identify the types of sugars involved in glucose metabolism Key Takeaways When blood sugar levels drop, glycogen is broken down into glucose -1-phosphate, which is then converted to glucose-6-phosphate and enters glycolysis for ATP production. In the liver, galactose is converted to glucose-6-phosphate in order to enter the glycolytic pathway. Fructose is converted into glycogen in the liver and then follows the same pathway as glycogen to enter glycolysis. Sucrose is broken down into glucose and fructose; glucose enters the pathway directly while fructose is converted to glycogen. disaccharide: A sugar, such as sucrose, maltose, or lactose, consisting of two monosaccharides combined together. glycogen: A polysaccharide that is the main form of carbohydrate storage in animals; converted to glucose as needed. monosaccharide: A simple sugar such as glucose, fructose, or deoxyribose that has a single ring. You have learned about the catabolism of glucose, which provides energy to living cells. But living things consume more than glucose for food. How does a turkey sandwich end up as ATP in your cells? This happens because all of the catabolic pathways for carbohydrates, proteins, and lipids eventually connect into glycolysis and the citric acid cycle pathways. Metabolic pathways should be thought of as porous; that is, substances enter from other pathways, and intermediates leave for other pathways. These pathways are not closed systems. Many of the substrates, intermediates, and products in a particular pathway are reactants in other pathways. Like sugars and amino acids, the catabo Continue reading >>

Glycolysis

Glycolysis

glycolysis, citric acid cycle, respiratory chain complete degradation of glucose for ATP production degradation of glucose for regeneration of NADPH synthesis of glucose from amino acids, lactate, or acetone Glucose is a key metabolite in human metabolism, and we will spend a good bit of time on the various pathways that are concerned with the utilization, storage, and regeneration of glucose. The first step in the degradation of glucose is glycolysis, which breaks down glucose to pyruvate. The main purpose of glycolysis is the generation of energy (ATP). A modest amount of ATP is produced in glycolysis directly, but much more ATP is formed downstream of glycolysis through the complete oxidation of pyruvate. An alternative pathway for complete glucose breakdown is the hexose monophosphate shunt, which produces NADPH rather than ATP. Both ATP and NADPH are needed in every cell, and accordingly both glycolysis and the hexose monophosphate shunt are ubiquitous. Glycogen is a polymeric storage form of glucose, not unlike starch, which is found in plants. Glycogen is most abundant in the liver and in striated muscle, 11 although some is found in other tissues also. Glycogen is synthesized when glucose supply is high, and its degradation helps to maintain the blood glucose level when we are fasting. When glycogen is depleted, more glucose is synthesized from scratch in gluconeogenesis. This pathways most important substrates are amino acids, which are obtained either from a protein-rich dietfor example, when we feast on meat exclusivelyor, during starvation, from breakdown of cellular protein, mainly in skeletal muscle. Gluconeogenesis occurs in the liver and in the kidneys. The place of glycolysis in glucose degradation As noted above, glycolysis is only the first stage of Continue reading >>

A Mathematical Model For Enzyme Clustering In Glucose Metabolism

A Mathematical Model For Enzyme Clustering In Glucose Metabolism

A Mathematical Model for Enzyme Clustering in Glucose Metabolism Scientific Reportsvolume8, Articlenumber:2696 (2018) We have recently demonstrated that the rate-limiting enzymes in human glucose metabolism organize into cytoplasmic clusters to form a multienzyme complex, the glucosome, in at least three different sizes. Quantitative high-content imaging data support a hypothesis that the glucosome clusters regulate the direction of glucose flux between energy metabolism and building block biosynthesis in a cluster size-dependent manner. However, direct measurement of their functional contributions to cellular metabolism at subcellular levels has remained challenging. In this work, we develop a mathematical model using a system of ordinary differential equations, in which the association of the rate-limiting enzymes into multienzyme complexes is included as an essential element. We then demonstrate that our mathematical model provides a quantitative principle to simulate glucose flux at both subcellular and population levels in human cancer cells. Lastly, we use the model to simulate 2-deoxyglucose-mediated alteration of glucose flux in a population level based on subcellular high-content imaging data. Collectively, we introduce a new mathematical model for human glucose metabolism, which promotes our understanding of functional roles of differently sized multienzyme complexes in both single-cell and population levels. Glucose metabolism consists of glycolysis and gluconeogenesis. Glycolysis converts glucose into pyruvate, whereas gluconeogenesis reverses the sequential reactions to produce glucose 1 . In normal healthycells, glucose is converted into pyruvate. Pyruvate then shuttles to mitochondria for oxidative phosphorylation in the presence of oxygen. If the oxygen Continue reading >>

4.5 Connections To Other Metabolic Pathways

4.5 Connections To Other Metabolic Pathways

4.5 Connections to Other Metabolic Pathways By the end of this section, you will be able to: Discuss the way in which carbohydrate metabolic pathways, glycolysis, and the citric acid cycle interrelate with protein and lipid metabolic pathways Explain why metabolic pathways are not considered closed systems You have learned about the catabolism of glucose, which provides energy to living cells. But living things consume more than just glucose for food. How does a turkey sandwich, which contains protein, provide energy to your cells? This happens because all of the catabolic pathways for carbohydrates, proteins, and lipids eventually connect into glycolysis and the citric acid cycle pathways ( Figure 4.24 ). Metabolic pathways should be thought of as porousthat is, substances enter from other pathways, and other substances leave for other pathways. These pathways are not closed systems. Many of the products in a particular pathway are reactants in other pathways. Connections of Other Sugars to Glucose Metabolism Glycogen, a polymer of glucose, is a short-term energy storage molecule in animals. When there is adequate ATP present, excess glucose is converted into glycogen for storage. Glycogen is made and stored in the liver and muscle. Glycogen will be taken out of storage if blood sugar levels drop. The presence of glycogen in muscle cells as a source of glucose allows ATP to be produced for a longer time during exercise. Sucrose is a disaccharide made from glucose and fructose bonded together. Sucrose is broken down in the small intestine, and the glucose and fructose are absorbed separately. Fructose is one of the three dietary monosaccharides, along with glucose and galactose (which is part of milk sugar, the disaccharide lactose), that are absorbed directly into the Continue reading >>

Frontiers | Glucose Metabolism Via The Entner-doudoroff Pathway In Campylobacter: A Rare Trait That Enhances Survival And Promotes Biofilm Formation In Some Isolates | Microbiology

Frontiers | Glucose Metabolism Via The Entner-doudoroff Pathway In Campylobacter: A Rare Trait That Enhances Survival And Promotes Biofilm Formation In Some Isolates | Microbiology

Front. Microbiol., 22 November 2016 | Glucose Metabolism via the Entner-Doudoroff Pathway in Campylobacter: A Rare Trait that Enhances Survival and Promotes Biofilm Formation in Some Isolates 1Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark 2Department of Zoology, University of Oxford, Oxford, UK 3NIHR Health Protection Research Unit in Gastrointestinal Infections, Oxford, UK 5School of Biological Sciences, University of Reading, Reading, UK 6Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield, UK Isolates of the zoonotic pathogen Campylobacter are generally considered to be unable to metabolize glucose due to lack of key glycolytic enzymes. However, the Entner-Doudoroff (ED) pathway has been identified in Campylobacter jejuni subsp. doylei and a few C. coli isolates. A systematic search for ED pathway genes in a wide range of Campylobacter isolates and in the C. jejuni/coli PubMLST database revealed that 1.7% of >6,000 genomes encoded a complete ED pathway, including both C. jejuni and C. coli from diverse clinical, environmental and animal sources. In rich media, glucose significantly enhanced stationary phase survival of a set of ED-positive C. coli isolates. Unexpectedly, glucose massively promoted floating biofilm formation in some of these ED-positive isolates. Metabolic profiling by gas chromatographymass spectrometry revealed distinct responses to glucose in a low biofilm strain (CV1257) compared to a high biofilm strain (B13117), consistent with preferential diversion of hexose-6-phosphate to polysaccharide in B13117. We conclude that while the ED pathway is rare amongst Campylobacter isolates causing human disease (the majority of which would Continue reading >>

Glycolysis

Glycolysis

Glucose G6P F6P F1,6BP GADP DHAP 1,3BPG 3PG 2PG PEP Pyruvate HK PGI PFK ALDO TPI GAPDH PGK PGM ENO PK Glycolysis The metabolic pathway of glycolysis converts glucose to pyruvate by via a series of intermediate metabolites. Each chemical modification (red box) is performed by a different enzyme. Steps 1 and 3 consume ATP (blue) and steps 7 and 10 produce ATP (yellow). Since steps 6-10 occur twice per glucose molecule, this leads to a net production of ATP. Summary of aerobic respiration Glycolysis (from glycose, an older term[1] for glucose + -lysis degradation) is the metabolic pathway that converts glucose C6H12O6, into pyruvate, CH3COCOO− + H+. The free energy released in this process is used to form the high-energy molecules ATP (adenosine triphosphate) and NADH (reduced nicotinamide adenine dinucleotide).[2][3] Glycolysis is a determined sequence of ten enzyme-catalyzed reactions. The intermediates provide entry points to glycolysis. For example, most monosaccharides, such as fructose and galactose, can be converted to one of these intermediates. The intermediates may also be directly useful. For example, the intermediate dihydroxyacetone phosphate (DHAP) is a source of the glycerol that combines with fatty acids to form fat. Glycolysis is an oxygen independent metabolic pathway, meaning that it does not use molecular oxygen (i.e. atmospheric oxygen) for any of its reactions. However the products of glycolysis (pyruvate and NADH + H+) are sometimes metabolized using atmospheric oxygen.[4] When molecular oxygen is used for the metabolism of the products of glycolysis the process is usually referred to as aerobic, whereas if no oxygen is used the process is said to be anaerobic.[5] Thus, glycolysis occurs, with variations, in nearly all organisms, both aerobic and a Continue reading >>

A General Overview Of The Major Metabolic Pathways

A General Overview Of The Major Metabolic Pathways

A general overview of the major metabolic pathways Assistant Professor, Universidade FernandoPessoa Metabolism is the set of chemical rections that occur in a cell, which enable it to keep living, growing and dividing.Metabolic processes are usually classified as: catabolism - obtaining energy and reducing power from nutrients. anabolism - production of new cell components, usually through processes that require energy and reducing power obtained from nutrient catabolism. There is a very large number of metabolic pathways. In humans, the most important metabolic pathways are: glycolysis - glucose oxidation in order to obtain ATP citric acid cycle (Krebs' cycle) - acetyl-CoA oxidation in order to obtain GTP and valuable intermediates. oxidative phosphorylation - disposal of the electrons released by glycolysis and citric acid cycle. Much of the energy released in this process can be stored as ATP. pentose phosphate pathway - synthesis of pentoses and release of the reducing power needed for anabolic reactions. urea cycle - disposal of NH4+ in less toxic forms fatty acid -oxidation - fatty acids breakdown into acetyl-CoA, to be used by the Krebs' cycle. gluconeogenesis - glucose synthesis from smaller percursors, to be used by the brain. Click on the picture to get information on each pathway Metabolic pathways interact in a complex way in order to allow an adequate regulation. This interaction includes the enzymatic control of each pathway, each organ's metabolic profile and hormone control . Flow is regulated in the gluconeogenesis-specific reactions. Pyruvate carboxilase is activated by acetyl-CoA, which signals the abundance of citric acid cycle intermediates, i.e., a decreased need of glucose. The citric acid cycle is regulated mostly by substrate availability, prod Continue reading >>

How Is Glucose Metabolized?

How Is Glucose Metabolized?

Glucose is metabolized into energy very rapidly during digestion.Photo Credit: Molekuul/iStock/Getty Images Adam Scott is a nutrition-minded father and husband. Currently he is pursuing a master's in nutrition and food studies at a major East Coast University. Soon he will be a Registered Dietitian and continue teaching proper nutrition. His work has been seen in many major newspapers. You absorb glucose, a simple sugar found in plants, directly into your bloodstream, where it acts as your body's fuel source. Without the ability to convert glucose into energy rapidly and efficiently, you would not be in good health. It's very important that your energy-metabolism system work efficiently. The metabolism process begins with digestion. Monosaccharides are absorbed into the bloodstream upon entering the small intestine. To control blood sugar, your body has three hormones: glucagon, insulin and epinephrine. Insulin, which your pancreas secretes when your blood sugar levels increase, helps along the transfer of glucose into your cells. Glucose metabolism is focused heavily in the muscles and liver, which receive more glucose than your other organs do because they have specific insulin receptors on their surface so that insulin can bind to them, thereby encouraging glucose entry and use in these cells. Upon entering the liver and muscles, the glucose is changed into glycogen by the process of glycogenesis. Glycogen stays in your liver and muscles until your glucose levels are low and you need energy. At this time, the epinephrine and glucogon hormones are released to stimulate the conversion of glycogen to glucose in a process called glycogenolysis. Once the glucose enters your cells, it is burned for energy and produces heat. This process also creates adenosine triphosphate Continue reading >>

Glucose Metabolism - Qiagen

Glucose Metabolism - Qiagen

Cells, particularly in skeletal muscle and the liver, store excess glucose as the polysaccharide glycogen, and quickly catabolize it again when necessary. Glycolysis, the TCA cycle, and the pentose phosphate pathway break down glucose from carbohydrates into the metabolites necessary for energy production. Gluconeogenesis is the process of creating glucose from other metabolites. Glycogen synthesis and degradation is necessary to create and use energy stores. Dysregulation of genes involved in glucose metabolism is common in a number of pathological conditions. In cancer, tumors often show decreased oxidative phosphorylation, even in the presence of sufficient oxygen. This phenomenon is due to enhanced transcription of glycolytic genes and/or reduced transcription of TCA cycle genes. Furthermore, the pathological consequences of diabetes and obesity involve gene expression changes in glucose metabolic pathways. ... Cells, particularly in skeletal muscle and the liver, store excess glucose as the polysaccharide glycogen, and quickly catabolize it again when necessary. Glycolysis, the TCA cycle, and the pentose phosphate pathway break down glucose from carbohydrates into the metabolites necessary for energy production. Gluconeogenesis is the process of creating glucose from other metabolites. Glycogen synthesis and degradation is necessary to create and use energy stores. Dysregulation of genes involved in glucose metabolism is common in a number of pathological conditions. In cancer, tumors often show decreased oxidative phosphorylation, even in the presence of sufficient oxygen. This phenomenon is due to enhanced transcription of glycolytic genes and/or reduced transcription of TCA cycle genes. Furthermore, the pathological consequences of diabetes and obesity involve Continue reading >>

Carbohydrate Metabolism

Carbohydrate Metabolism

Carbohydrate metabolism denotes the various biochemical processes responsible for the formation, breakdown, and interconversion of carbohydrates in living organisms. Carbohydrates are central to many essential metabolic pathways.[1] Plants synthesize carbohydrates from carbon dioxide and water through photosynthesis, allowing them to store energy absorbed from sunlight internally.[2] When animals and fungi consume plants, they use cellular respiration to break down these stored carbohydrates to make energy available to cells.[2] Both animals and plants temporarily store the released energy in the form of high energy molecules, such as ATP, for use in various cellular processes.[3] Although humans consume a variety of carbohydrates, digestion breaks down complex carbohydrates into a few simple monomers for metabolism: glucose, fructose, and galactose.[4] Glucose constitutes about 80% of the products, and is the primary structure that is distributed to cells in the tissues, where it is broken down or stored as glycogen.[3][4] In aerobic respiration, the main form of cellular respiration used by humans, glucose and oxygen are metabolized to release energy, with carbon dioxide and water as byproducts.[2] Most of the fructose and galactose travel to the liver, where they can be converted to glucose.[4] Some simple carbohydrates have their own enzymatic oxidation pathways, as do only a few of the more complex carbohydrates. The disaccharide lactose, for instance, requires the enzyme lactase to be broken into its monosaccharide components, glucose and galactose.[5] Metabolic pathways[edit] Overview of connections between metabolic processes. Glycolysis[edit] Glycolysis is the process of breaking down a glucose molecule into two pyruvate molecules, while storing energy released Continue reading >>

Interrelation Between The Various Pathways Of Glucose Metabolism In The Rat Lens*

Interrelation Between The Various Pathways Of Glucose Metabolism In The Rat Lens*

Volume 3, Issue 2 , June 1964, Pages 99-104 Interrelation between the various pathways of glucose metabolism in the rat lens * Author links open overlay panel RuthLevari12 ErnstWertheimer12 WalterKornblueth12 Get rights and content The activity of the hexose monophosphate shunt in the rat lens rose in proportion to the increased concentrations of glucose in the incubating medium. Under the same conditions, lactic acid production increased only up to 50%. Preincubation of the lens with dulcitol caused a depression of both the glycolysis and the hexose monophosphate shunt. The shunt activity was increased in the presence of added insulin when the medium contained 10 mg of glucose, or less, per ml, but it was not affected by the presence of 20 mg of glucose per ml. Incubation in media containing increasing concentrations of fructose caused a proportional rise in lactic acid production. The addition of pyruvic acid to the medium enhanced the hexose monophosphate shunt, whereas lactic acid depressed it. Some interrelationships between the sorbitol pathway, the hexose monophosphate shunt and the glycolytic pathway in the rat lens are discussed. Continue reading >>

Glucose Metabolism In Legionella Pneumophila: Dependence On The Entner-doudoroff Pathway And Connection With Intracellular Bacterial Growth

Glucose Metabolism In Legionella Pneumophila: Dependence On The Entner-doudoroff Pathway And Connection With Intracellular Bacterial Growth

DNA manipulations.PCR was performed with Ex Taq or LA Taq DNA polymerase (Takara Bio, Shiga, Japan) or KOD FX DNA polymerase (Toyobo, Osaka, Japan) in a T1 Thermocycler (Biometra, Goettingen, Germany). Blunting of DNA ends was achieved with a DNA Blunting Kit (Takara Bio). Restriction endonucleases were purchased from Toyobo. All enzyme reactions were carried out as recommended by the suppliers. Purification of PCR products and preparation of plasmid DNA were carried out by DNA with a Gel Band Purification Kit (GE Healthcare, Buckinghamshire, United Kingdom) and a Wizard Plus Kit (Promega, Madison, WI), respectively. Oligonucleotide primers.The primers used are listed in Table S1 in the supplemental material. They were designed according to the genomic sequence of strain Philadelphia 1 (NC_002942). Construction of gene-disrupted mutants.The construction of gene-disrupted mutants was carried out by inserting a Kmr cassette, Mini-Tn5 Km, excised from pUT-mini-Tn5 Km ( 4 ), into each of the target genes, i.e., edd, glk, eda, and ywtG, in the following steps. (i) Appropriate DNA segments were amplified with the primers 1F/1R, 2F/2R, 3F/3R, and 4F/4R (see Table S1 in the supplemental material) to give the products edd, glk, eda, and ywtG, respectively (Fig. 1B ); (ii) TA cloning of the PCR products with pGEM-T Easy gave pHRD1, pHRD2, pHRD3, and pHRD4, respectively; (iii) for pHRD1 and pHRD2, insertion of the SmaI-excised Kmr cassette into their blunted BanIII sites gave pHRD1Km and pHRD2Km; in pHRD3 and pHRD4, BamHI sites were introduced using the primers 5F/5R or 6F/6R and a Quick Change Site-Directed Mutagenesis Kit (Stratagene, CA) to give pHRD3B and pHRD4B, which in turn gave rise to pHRD3Km and pHRD4Km by accepting the BamHI-excised Kmr cassette at their BamHI sites; ( Continue reading >>

Metabolic Pathways

Metabolic Pathways

There are three groups of molecules that form the core building blocks and fuel substrates in the body: carbohydrates (glucose and other sugars); proteins and their constituent amino acids; and lipids and their constituent fatty acids. The biochemical processes that allow these molecules to be synthesized and stored (anabolism) or broken down to generate energy (catabolism) are referred to as metabolic pathways. Glucose metabolism involves the anabolic pathways of gluconeogenesis and glycogenesis, and the catabolic pathways of glycogenolysis and glycolysis. Lipid metabolism involves the anabolic pathways of fatty acid synthesis and lipogenesis and the catabolic pathways of lipolysis and fatty acid oxidation. Protein metabolism involves the anabolic pathways of amino acid synthesis and protein synthesis and the catabolic pathways of proteolysis and amino acid oxidation. Under conditions when glucose levels inside the cell are low (such as fasting, sustained exercise, starvation or diabetes), lipid and protein catabolism includes the synthesis (ketogenesis) and utilization (ketolysis) of ketone bodies. The end products of glycolysis, fatty acid oxidation, amino acid oxidation and ketone body degradation can be oxidised to carbon dioxide and water via the sequential actions of the tricarboxylic acid cycle and oxidative phosphorylation, generating many molecules of the high energy substrate adenosine triphosphate (ATP). Interplay between metabolic pathways The interplay between glucose metabolism, lipid metabolism, ketone body metabolism and protein and amino acid metabolism is summarized in Figure 1. Amino acids can be a source of glucose synthesis as well as energy production and excess glucose that is not required for energy production can be stored as glycogen or metabo Continue reading >>

Lactate, Not Pyruvate, Is The End Product Of Glucose Metabolism Via Glycolysis

Lactate, Not Pyruvate, Is The End Product Of Glucose Metabolism Via Glycolysis

Lactate, Not Pyruvate, Is the End Product of Glucose Metabolism via Glycolysis Glucose is the monosaccharide utilized by most eukaryotes to generate metabolic energy, and in the majority of eukaryotic systems, glycolysis is the first biochemical pathway where glucose breaks down via a series of enzymatic reactions to produce relatively small amounts of adenosinetriphosphate (ATP). In 1940, the sequence of these glycolytic reactions was elucidated, a breakthrough that was recognized as the very first such elucidation of a biochemical pathway in history. Accordingly, the glycolytic breakdown of glucose ends up either with pyruvate as the final product under aerobic conditions or with lactate, to which pyruvate is being reduced, under anaerobic conditions. Consequently, pyruvate has been designated and is held to be the substrate of the mitochondrial tricarboxylic acid cycle, where it is completely oxidized into CO2 and H2O, while lactate has been defined and being held to as a useless dead-end product, poisonous at times, of which cells must discard off quickly. More than four decades after the glycolytic pathway has been elucidated, studies of both muscle and brain tissues have suggested that lactate is not necessarily a useless end product of anaerobic glycolysis and may actually play a role in bioenergetics. These studies have shown that muscle and brain tissues can oxidize and utilize lactate as a mitochondrial energy substrate. These results have been met with great skepticism, but a large number of publications over the past quarter of a century have strengthened the idea that lactate does play an important and, possibly, a crucial role in energy metabolism. These findings have shed light on a major drawback of the originally proposed aerobic version of the glycolyt Continue reading >>

Glucose Metabolism - Pathway Support - Pathways

Glucose Metabolism - Pathway Support - Pathways

All pathways communicate together to some degree. Prior to targeting a specific pathway, one must identify, and restore, the common fundamental elements. Login or create an account to earn points. Glucose has the amazing ability to fuel various energy pathways. Understanding the epigenetic control of glucose metabolism allows us to make better decisions. Simply because glucose levels rise does not mean that it will be utilized appropriately. One must evaluate each step within the Glucose Metabolism Pathway and see where potential blockages exist. Key signs of glucose imbalance are fatigue and the inability to think clearly. By supplementing with NADH + CoQ10 , one may bypass many steps of the glucose pathway and thereby support mitochondrial respiration.* I can tell this is a superior Vit C. I'm taking it with the Glutathione. I don't remember where Vit C fits in with the methylation cycle. I'm still tweaking all of my supplements, but this is awesome stuff." I feel amazing now that I've started taking HomocysteX Plus. The combo of B vitamins seems to be just right for me and I'm not always easy to please with having a double C677T MTHFR mutation!!" Family friend recommended Lactase Drops from SeekingHealth.com. Could not be more pleased with product. Not only a great product, but also great customer service. The first bottle we received was damaged and the majority of the contents had leaked out. Contacted SeekingHealth.com that day and received a free replacement bottle within 2 days!" I am a repeat customer who is very pleased with how good I feel on this multi!!" How many supplement companies have a doctor sharing a wealth of information on how to take these vitamins, anticipated reactions, side effects, how to move forward with different supplements. This doesn't Continue reading >>

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