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1.
Arch Endocrinol Metab ; 63(4): 376-384, 2019 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-31365624

RESUMO

OBJECTIVE: To test the influence of oral fructose and glucose dose-response solutions in blood glucose (BG), glucagon, triglycerides, uricaemia, and malondialdehyde in postprandial states in type 1 diabetes mellitus (T1DM) patients. SUBJECTS AND METHODS: The study had a simple-blind, randomized, two-way crossover design in which T1DM patients were selected to receive fructose and glucose solutions (75g of sugars dissolved in 200 mL of mineral-water) in two separate study days, with 2-7 weeks washout period. In each day, blood samples were drawn after 8h fasting and at 180 min postprandial to obtain glucose, glucagon, triglycerides, uric acid, lactate, and malondialdehyde levels. RESULTS: Sixteen T1DM patients (seven men) were evaluated, with a mean age of 25.19 ± 8.8 years, a mean duration of disease of 14.88 ± 4.73 years, and glycated hemoglobin of 8.13 ± 1.84%. Fructose resulted in lower postprandial BG levels than glucose (4.4 ± 5.5 mmol/L; and 12.9 ± 4.1 mmol/L, respectively; p < 0.01). Uric acid levels increased after fructose (26.1 ± 49.9 µmol/L; p < 0.01) and reduced after glucose (-13.6 ± 9.5 µmol/L; p < 0.01). The malondialdehyde increased after fructose (1.4 ± 1.6 µmol/L; p < 0.01) and did not change after glucose solution (-0.2 ± 1.6 µmol/L; p = 0.40). Other variables did not change. CONCLUSIONS: Fructose and glucose had similar sweetness, flavor and aftertaste characteristics and did not change triglycerides, lactate or glucagon levels. Although fructose resulted in lower postprandial BG than glucose, it increased uric acid and malondialdehyde levels in T1DM patients. Therefore it should be used with caution. ClinicalTrials.gov registration: NCT01713023.


Assuntos
Diabetes Mellitus Tipo 1/metabolismo , Frutose/metabolismo , Glucose/metabolismo , Período Pós-Prandial/efeitos dos fármacos , Edulcorantes/metabolismo , Adolescente , Adulto , Glicemia/análise , Glicemia/efeitos dos fármacos , Estudos Cross-Over , Relação Dose-Resposta a Droga , Tolerância a Medicamentos , Feminino , Frutose/farmacologia , Glucose/farmacologia , Humanos , Masculino , Malondialdeído/sangue , Pessoa de Meia-Idade , Projetos Piloto , Método Simples-Cego , Soluções/farmacologia , Edulcorantes/farmacologia , Paladar/efeitos dos fármacos , Triglicerídeos/sangue , Ácido Úrico/sangue , Adulto Jovem
2.
Bioresour Technol ; 289: 121673, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31260936

RESUMO

d-Allulose is a promising low-calorie sweetener especially for diabetes and obesity patients. The functionalized polyhydroxyalkanoate (PHA) nano-beads decorated with d-tagatose 3-epimerase (DTE) was produced in recombinant endotoxin-free ClearColi, whereby the expression, purification, and immobilization of the active DTE were efficiently combined into one step. The immobilized DTE exhibited remarkable enzyme activity of 649.3 U/g beads and extremely high stability at a harsh working condition (pH 7.0-8.0, 65 °C). When DTE-PHA beads were subjected to enzymatic synthesis of d-allulose, a maximum conversion rate of 33% can be achieved at pH 7.0 and 65 °C for 3 h, and DTE-PHA beads retained about 80% of its initial activity after 8 continuous cycles. Moreover, the d-allulose/d-fructose binary mixture can be simply separated by a single cation exchange resin-equipped chromatography. Taken together, DTE-PHA beads are promising and robust nano-biocatalysts that will remarkably simplify the production procedures of d-allulose, contributing to its cost-effective production.


Assuntos
Frutose/metabolismo , Poli-Hidroxialcanoatos/metabolismo , Biocatálise , Análise Custo-Benefício , Concentração de Íons de Hidrogênio , Nanoestruturas , Racemases e Epimerases/metabolismo
3.
Medicina (B Aires) ; 79(2): 137-143, 2019.
Artigo em Espanhol | MEDLINE | ID: mdl-31048279

RESUMO

Certain organoleptic modifications by way of processing and cooking foods at high temperatures in dry heat, make them especially appetizing and objects of addiction. It results from Maillard reaction, or glycation, consisting of the non-enzymatic union between carbonyl groups, mainly from reducing sugars as glucose and fructose, with the amino group of proteins and nucleic acids. In addition to physical changes, also the chemical structure and function of these compounds are changed. Besides exogenous glycation generated during the cooking of foods, recently in situ glycation has been reported in the intestinal lumen during digestion, when certain non-glycated foods are combined with fructose at the time of ingestion. In addition, endogenous glycation, which correlates in the extracellular mainly with blood glucose and in the intracellular with glycolysis metabolites and fructose, is specially significant. Since the 70s, with the frequent sucrose replacement by fructose, much more reactive than glucose, the presence of glycation products in processed foods and soft drinks increased.Pathogenic effects of these compounds, also called glycotoxins, are known to contribute to oxidative stress and inflammation. This increases progression of chronic diseases, well documented in diabetes, renal insuficiency, cardiovascular disease and aging process, and are being explore d in many other chronic diseases as neurodegenerative disorders and early aging. Based on the knowledge achieved so far, measures to preserve health are described by attending ways of cooking and processing foods, besides recommendations for life habits and antioxidants dietary intakes for inhibition or antagonism on glycotoxins.


Assuntos
Alimentos , Produtos Finais de Glicação Avançada/metabolismo , Reação de Maillard , Frutose/metabolismo , Glucose/metabolismo , Produtos Finais de Glicação Avançada/química , Humanos , Estresse Oxidativo/fisiologia , Fatores de Risco
4.
Bioelectrochemistry ; 129: 1-9, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31063949

RESUMO

This review summarizes the bioelectrocatalytic properties of d-fructose dehydrogenase (FDH), while taking into consideration its enzymatic characteristics. FDH is a membrane-bound flavohemo-protein with a molecular mass of 138 kDa, and it catalyzes the oxidation of d-fructose to 5-keto-d-fructose. The characteristic feature of FDH is its strong direct-electron-transfer (DET)-type bioelectrocatalytic activity. The pathway of the DET-type reaction is discussed. An overview of the application of FDH-based bioelectrocatalysis to biosensors and biofuel cells is also presented, and the benefits and problems associated with it are extensively discussed.


Assuntos
Bactérias/enzimologia , Fontes de Energia Bioelétrica , Técnicas Biossensoriais/métodos , Desidrogenases de Carboidrato/metabolismo , Frutose/metabolismo , Sequência de Aminoácidos , Bactérias/química , Bactérias/metabolismo , Biocatálise , Fontes de Energia Bioelétrica/microbiologia , Técnicas Biossensoriais/instrumentação , Desidrogenases de Carboidrato/química , Transporte de Elétrons , Oxirredução
5.
Nat Commun ; 10(1): 1534, 2019 04 04.
Artigo em Inglês | MEDLINE | ID: mdl-30948717

RESUMO

Tomato flavor has changed over the course of long-term domestication and intensive breeding. To understand the genetic control of flavor, we report the meta-analysis of genome-wide association studies (GWAS) using 775 tomato accessions and 2,316,117 SNPs from three GWAS panels. We discover 305 significant associations for the contents of sugars, acids, amino acids, and flavor-related volatiles. We demonstrate that fruit citrate and malate contents have been impacted by selection during domestication and improvement, while sugar content has undergone less stringent selection. We suggest that it may be possible to significantly increase volatiles that positively contribute to consumer preferences while reducing unpleasant volatiles, by selection of the relevant allele combinations. Our results provide genetic insights into the influence of human selection on tomato flavor and demonstrate the benefits obtained from meta-analysis.


Assuntos
Frutas/genética , Estudo de Associação Genômica Ampla , Lycopersicon esculentum/genética , Ácido Cítrico/metabolismo , Frutose/genética , Frutose/metabolismo , Frutas/metabolismo , Glucose/genética , Glucose/metabolismo , Lycopersicon esculentum/metabolismo , Malatos/metabolismo
6.
Food Chem ; 289: 285-291, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-30955614

RESUMO

Various metal oxides were used as co-catalysts to improve the production of alkyl lactate over Sn-Beta-P. WO3 exhibited the best promotion effect. The yield of MLA increased from 25% (6.5 g L-1) over Sn-Beta-P (0.2 g) to 52% (13.4 g L-1) over WO3 (0.1 g) and Sn-Beta-P (0.1 g) at 160 °C for 5 h and 3.1 wt% of glucose concentration. MLA yield of 38% was attained even at glucose concentration of 10 wt% and the space-time yield reached 7.1 g L-1 h-1. The action mechanism of WO3 was investigated. Fine WO3 particles adsorbed on surface of Sn-Beta-P in reaction media and decreased the silanol defects of Sn-Beta-P. This promotes retro-aldol of fructose, the rate-determining step of whole reaction, thus facilitated the formation of MLA. Kinetic studies indicate that the presence of WO3 decreased the activation energy of the retro-aldol of fructose. The binary solid WO3 and Sn-Beta-P is recyclable.


Assuntos
Glucose/metabolismo , Ácido Láctico/metabolismo , Óxidos/química , Tungstênio/química , Zeolitas/química , Catálise , Frutose/química , Frutose/metabolismo , Glucose/química , Cinética , Ácido Láctico/análogos & derivados , Estanho/química
7.
Mol Biotechnol ; 61(6): 432-441, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30963480

RESUMO

D-Allulose is a rare monosaccharide that exists in extremely small quantities in nature, and it is also hard to prepare at a large scale via chemical or enzyme synthetic route due to low conversion and downstream separation complexity. Using D-psicose epimerase and L-rhamnulose kinase, a method enabling high conversion of D-allulose from D-fructose without the need for a tedious isomer separation step was established recently. However, this method requires expensive ATP to facilitate the reaction. In the present study, an ATP regenerate system was developed coupling with polyphosphate kinase. In our optimized reaction with purified enzymes, the conversion rate of 99% D-fructose was achieved at the concentrations of 2 mM ATP, 5 mM polyphosphate, 20 mM D-fructose, and 20 mM Mg2+ when incubated at 50 °C and at pH 7.5. ATP usage can be reduced to 10% of the theoretical amount compared to that without the ATP regeneration system. A fed-batch mode was also studied to minimize the inhibitory effect of polyphosphate. The biosynthetic system reported here offers a potential and promising platform for the conversion of D-fructose into D-allulose at reduced ATP cost.


Assuntos
Trifosfato de Adenosina/metabolismo , Carboidratos Epimerases/metabolismo , Frutose/metabolismo , Fosfotransferases (Aceptor do Grupo Álcool)/metabolismo , Proteínas Recombinantes de Fusão/metabolismo , Biotransformação , Carboidratos Epimerases/genética , Cátions Bivalentes , Clonagem Molecular , Ensaios Enzimáticos , Escherichia coli/genética , Escherichia coli/metabolismo , Frutose/biossíntese , Expressão Gênica , Vetores Genéticos/química , Vetores Genéticos/metabolismo , Magnésio/metabolismo , Fosfotransferases (Aceptor do Grupo Álcool)/genética , Polifosfatos/metabolismo , Proteínas Recombinantes de Fusão/genética , Frações Subcelulares/química , Frações Subcelulares/metabolismo , Thermotoga maritima/genética , Thermotoga maritima/metabolismo
8.
Food Chem ; 286: 434-440, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-30827630

RESUMO

An efficient system for biotransformation of sucrose to fructooligosaccharides (FOS) was obtained using Aspergillus tamarii NKRC 1229 mycelial fructosyltransferase (m-FTase). Zymographic analysis confirmed mycelial localization of the FTase (36 U/g) and lyophilized fungal pellets were used for bioconversion. m-FTase had molecular weight ∼75 kDa with optimum activity at pH 7.0 and 20 °C. FOS production after parametric optimization (sucrose - 50% w/v, m-FTase dose - 4.5% w/v, inoculum age - 48 h and incubation time - 24 h) reached 325 g/L (55% yield) with 14% residual sucrose, 25% glucose and 6% fructose. FTase activity was enhanced after pre-treatment with organic solvents and SDS. FOS was purified in a single step using gel filtration matrix, Bio-Gel P2. FOS was characterized using Diffusion ordered spectroscopy-Nuclear Magnetic Resonance (1H DOSY-NMR) and Fourier-transform infrared spectroscopy (FTIR). Continuous generation of FOS was achieved using recyclable mycelia upto 10 consecutive cycles.


Assuntos
Aspergillus/enzimologia , Hexosiltransferases/metabolismo , Oligossacarídeos/biossíntese , Aspergillus/genética , Frutose/metabolismo , Espectroscopia de Ressonância Magnética , Micélio/enzimologia , Oligossacarídeos/isolamento & purificação , Solventes/química , Espectroscopia de Infravermelho com Transformada de Fourier , Sacarose/metabolismo
9.
Int J Mol Sci ; 20(5)2019 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-30841536

RESUMO

One of the most important threats to global human health is the increasing incidences of metabolic pathologies (including obesity, type 2 diabetes and non-alcoholic fatty liver disease), which is paralleled by increasing consumptions of hypercaloric diets enriched in simple sugars. The challenge is to identify the metabolic pathways affected by the excessive consumption of these dietary components when they are consumed in excess, to unravel the molecular mechanisms leading to metabolic pathologies and identify novel therapeutic targets to manage them. Mechanistic (mammalian) target of rapamycin (mTOR) has emerged as one of the key molecular nodes that integrate extracellular signals, such as energy status and nutrient availability, to trigger cell responses that could lead to the above-mentioned diseases through the regulation of lipid and glucose metabolism. By activating mTOR signalling, excessive consumption of simple sugars (such as fructose and glucose), could modulate hepatic gluconeogenesis, lipogenesis and fatty acid uptake and catabolism and thus lipid deposition in the liver. In the present review we will discuss some of the most recent studies showing the central role of mTOR in the metabolic effects of excessive simple sugar consumption.


Assuntos
Frutose/metabolismo , Glucose/metabolismo , Fígado/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Animais , Humanos , Metabolismo dos Lipídeos , Transdução de Sinais
10.
Food Chem ; 288: 102-107, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-30902269

RESUMO

A new bi-enzymatic catalyst has been produced by precipitation and crosslinking (combi-CLEAs) of ß-galactosidase and glucose isomerase for catalyzing the cascade reactions of lactose conversion into fructose, producing a lactose-fructose syrup (LFS). Glucose isomerase was chemically aminated to increase its reactive surface groups for favour the crosslinking step. The effect of ß-galactosidase to glucose isomerase activity ratio and glutaraldehyde to protein mass ratio in combi-CLEAs production was evaluated. The selected combi-catalyst was successfully used in the production of fructose syrup from lactose in a single reaction vessel. The biocatalyst could be used at least in five sequential batches of LFS production, remaining fully stable after a total of 50 h of reaction, obtaining a product of constant quality. A robust bi-enzymatic catalyst was produced that can be repeatedly used in LFS production, an attractive mild sweetener for the dairy food industry.


Assuntos
Frutose/metabolismo , Lactose/metabolismo , beta-Galactosidase/metabolismo , Aldose-Cetose Isomerases , Catálise , Glucose/metabolismo , Glutaral/metabolismo
11.
Planta ; 249(6): 1921-1947, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30891648

RESUMO

MAIN CONCLUSION: Among seaweed groups, brown algae had characteristically high concentrations of mannitol, and green algae were characterised by fructose. In red algae, metabolite profiles of individual species should be evaluated. Seaweeds are metabolically different from terrestrial plants. However, general metabolite profiles of the three major seaweed groups, the brown, red, and green algae, and the effect of various extraction methods on metabolite profiling results have not been comprehensively explored. In this study, we evaluated the water-soluble metabolites in four brown, five red, and two green algae species collected from two sites in northern Japan, located in the Sea of Japan and the Pacific Ocean. Freeze-dried seaweed samples were processed by methanol-water extraction with or without chloroform and analysed by capillary electrophoresis- and liquid chromatography-mass spectrometry for metabolite characterisation. The metabolite concentration profiles showed distinctive characteristic depends on species and taxonomic groups, whereas the extraction methods did not have a significant effect. Taxonomic differences between the various seaweed metabolite profiles were well defined using only sugar metabolites but no other major compound types. Mannitol was the main sugar metabolites in brown algae, whereas fructose, sucrose, and glucose were found at high concentrations in green algae. In red algae, individual species had some characteristic metabolites, such as sorbitol in Pyropia pseudolinearis and panose in Dasya sessilis. The metabolite profiles generated in this study will be a resource and provide guidance for nutraceutical research studies because the information about metabolites in seaweeds is still very limited compared to that of terrestrial plants.


Assuntos
Clorófitas/metabolismo , Metaboloma , Feófitas/metabolismo , Rodófitas/metabolismo , Alga Marinha/metabolismo , Análise por Conglomerados , Frutose/metabolismo , Manitol/metabolismo , Especificidade da Espécie
12.
Toxicon ; 161: 57-64, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-30831148

RESUMO

Venom from the parasitoid wasp Nasonia vitripennis dramatically elevates sorbitol levels in its natural fly hosts. In humans, sorbitol elevation is associated with complications of diabetes. Here we demonstrate that venom also induces this disease-relevant phenotype in human cells, and investigate possible pathways involved. Key findings are that (a) low doses of Nasonia venom elevate sorbitol levels in human renal mesangial cells (HRMCs) without changing glucose or fructose levels; (b) venom is a much more potent inducer of sorbitol elevation than glucose; (c) low venom doses significantly alter expression of genes involved in sterol and alcohol metabolism, transcriptional regulation, and chemical/stimulus response; (d) although venom treatment does not alter expression of the key sorbitol pathway gene aldose reductase (AR); (e) venom elevates expression of a related gene implicated in diabetes complications (AKR1C3) as well as the fructose metabolic gene (GFPT2). Although elevated sorbitol is accepted as a major contributor to secondary complications of diabetes, the molecular mechanism of sorbitol regulation and its contribution to diabetes complications are not fully understood. Our findings suggest that genes other than AR could contribute to sorbitol regulation, and more broadly illustrate the potential of parasitoid venoms for medical application.


Assuntos
Regulação da Expressão Gênica/efeitos dos fármacos , Rim/efeitos dos fármacos , Células Mesangiais/efeitos dos fármacos , Sorbitol/metabolismo , Venenos de Vespas/farmacologia , Aldeído Redutase/metabolismo , Membro C3 da Família 1 de alfa-Ceto Redutase/metabolismo , Animais , Contagem de Células , Frutose/metabolismo , Glucose/metabolismo , Glutamina-Frutose-6-Fosfato Transaminase (Isomerizante)/metabolismo , Humanos , Rim/citologia , Rim/metabolismo , Células Mesangiais/metabolismo , Cultura Primária de Células
13.
J Med Food ; 22(5): 538-541, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30864849

RESUMO

Nopal is used in Mexico as both food and traditional medicine for metabolic diseases. Our aim was to analyze the effect of the chronic administration of mucilage fiber extracted from nopal (Opuntia ficus indica; 500 mg/kg body weight per day) on male Wistar rats on a high-fructose diet (HFD). After which three groups were administered one of the following for 30 days: whole-fresh nopal mixed in water, mucilage, and control. Metabolic and hemodynamic parameters (triglycerides, cholesterol, fasting glucose, oral glucose tolerance test, blood pressure, and abdominal circumference) were determined. Rats administered nopal and mucilage had lower levels of triglycerides and diastolic arterial pressure than control, but only nopal had significant differences. Furthermore, systolic and diastolic pressure were higher in the control group. Thus, whole nopal and mucilage improve metabolic parameters in rats fed a HFD.


Assuntos
Fibras na Dieta/metabolismo , Frutose/efeitos adversos , Síndrome Metabólica/dietoterapia , Opuntia/química , Extratos Vegetais/metabolismo , Animais , Glicemia/metabolismo , Colesterol/metabolismo , Frutose/metabolismo , Teste de Tolerância a Glucose , Humanos , Masculino , Síndrome Metabólica/etiologia , Síndrome Metabólica/metabolismo , Ratos , Ratos Wistar , Triglicerídeos/metabolismo
14.
Arch Dermatol Res ; 311(4): 317-324, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30847563

RESUMO

We previously showed that topical application of hexoses such as fructose accelerates barrier recovery after disruption. We also showed that various hexoses and polyols interact with phospholipid and alter the phase transition temperature. Thus, we hypothesized that the improvement of barrier recovery by hexoses and polyols might be related to the interaction with phospholipid. Here, we tested this idea by examining the effects of xylitol (a component of some skin-care products) and fructose on lipid dynamics in an epidermal-equivalent model at the single-cell level by means of two-photon microscopy after staining with Laurdan, a fluorescent dye sensitive to the physical properties of its membrane environment. First, we confirmed that topical application of xylitol aqueous solution on tape-stripped human skin accelerated barrier recovery. Then, we examined changes of lipid fluidity in the epidermal-equivalent model after application of water or an aqueous solution of xylitol or fructose. Application of xylitol and/or fructose increased the lipid fluidity in the uppermost part of the stratum granulosum layer, compared to treatment with water alone, and accelerated the exocytosis of lamellar bodies to the intercellular domain between stratum corneum and stratum granulosum. Our results support the idea that the improvement of epidermal barrier homeostasis upon topical application of xylitol or fructose is due to increased lipid fluidity in the uppermost layer of the stratum granulosum, which enables accelerated release of lipid from the stratum granulosum, thereby improving the lamellar structure and accelerating epidermal permeability barrier recovery.


Assuntos
Permeabilidade da Membrana Celular , Epiderme/fisiologia , Frutose/metabolismo , Queratinócitos/fisiologia , Bicamadas Lipídicas/metabolismo , Xilitol/metabolismo , Adulto , Células Cultivadas , Exocitose , Homeostase , Humanos , Lipídeos/análise , Masculino , Fluidez de Membrana , Modelos Biológicos , Análise de Célula Única , Adulto Jovem
15.
Rev Med Inst Mex Seguro Soc ; 56(5): 491-504, 2019 Jan 28.
Artigo em Espanhol | MEDLINE | ID: mdl-30777418

RESUMO

Scientific evidence has identified that the excessive consumption of products made from high-fructose corn syrup is a trigger for obesity, whose prevalence increased in recent years. Due to the metabolic characteristics of fructose, a rapid gastric emptying is produced, altering signals of hunger-satiety and decreasing the appetite. In addition to the hepatic level during catabolism, triose phosphate is generated and adenosine triphosphate (ATP) is reduced, producing uric acid. Triose phosphate triggers the synthesis of fatty acids that increase the production and accumulation of triglycerides, diacylglycerols and ceramides that induce insulin resistance. Hyperlipidemia, insulin resistance and hyperuricemia contribute to the development of hypertension, cardiovascular disease, kidney failure, non-alcoholic fatty liver disease and some kinds of cancer. Understanding the molecular mechanisms and signaling pathways altered by the consumption of fructose is relevant to understand the development of metabolic diseases, as well as to seek therapeutic strategies to improve quality of life.


Assuntos
Metabolismo dos Carboidratos , Açúcares da Dieta/efeitos adversos , Frutose/efeitos adversos , Metabolismo dos Lipídeos , Doenças Metabólicas/etiologia , Biomarcadores/metabolismo , Açúcares da Dieta/metabolismo , Frutose/metabolismo , Humanos , Hiperlipidemias/etiologia , Hiperuricemia/etiologia , Resistência à Insulina , Doenças Metabólicas/metabolismo
16.
An Acad Bras Cienc ; 91(1): e20170705, 2019 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-30785495

RESUMO

Fructose consumption has increased worldwide, and it has been associated with the development of metabolic diseases such as insulin resistance (IR) and steatosis. The aim was to evaluate if lower fructose concentrations may cause pancreatic structural abnormalities, leading to a glucose intolerance without steatosis in male rats. Young male rats orally received 7% fructose solution for 12 weeks. Body weight, food, water, and energy intake were measured. An oral glucose tolerance test (OGTT) was performed. After final experimental period, all rats were anaesthetized and killed. Blood samples were collected for biochemical analyses and organs (liver and pancreas) were processed for morphological analyses. Fructose consumption was not associated with lipid accumulation in liver. However, fructose administration was associated with an increased area under curve from OGTT and an increased percentage of insulin-positive cells, high beta cell mass and reduced pancreatic islet area. Fructose supplementation (7%) did not cause steatosis, but it led to abnormal morphology and function of pancreatic islet cells, contributing for glucose intolerance development. Our findings demonstrate that even low fructose concentrations may cause deleterious effects in animals.


Assuntos
Glicemia/efeitos dos fármacos , Frutose/administração & dosagem , Animais , Modelos Animais de Doenças , Água Potável , Frutose/metabolismo , Teste de Tolerância a Glucose , Resistência à Insulina , Ilhotas Pancreáticas/efeitos dos fármacos , Ilhotas Pancreáticas/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Ratos , Ratos Wistar
17.
Chem Biodivers ; 16(5): e1800479, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30807682

RESUMO

This study describes the 1 H-NMR-based metabolomics profiling of juices from citrus fruits harvested in the state of Veracruz, México. The hydrophilic profile of commercial lemons (Agrio and Persian), tangerines (Fremont and Mónica), oranges (Valencia and Washington Navel), and grapefruits (Red Ruby and Rio Red) was determined. According to our results, 35 metabolites were identified in the 1 H-NMR profiling. The statistical differences obtained by PCA and OPLS-DA revealed that specific amino acids, sugars, and organic acids were differential metabolites in the species and cultivars studied. High endogenous levels of sucrose (10-190 mM), α-glucose, ß-glucose (α- and ß-isomers, 40-205 mm), and fructose (36-170 mm) were detected in the juices of grapefruits, oranges, and tangerines, whereas citric acid (40-530 mm) was the principal organic acid in the juices of lemons. To calculate the specific amounts of metabolites from these species and their cultivars, the results were finely analyzed using the qNMR method. According to these calculations, Valencia oranges had the highest concentration of ascorbic acid (>2 mm). The described 1 H-NMR method is highly reproducible, inexpensive, and highly robust in comparison to other analytical methods used to determine the hydrophilic profile of citrus juices.


Assuntos
Citrus/metabolismo , Sucos de Frutas e Vegetais/análise , Espectroscopia de Ressonância Magnética/métodos , Metaboloma , Aminoácidos/metabolismo , Ácido Ascórbico/análise , Ácido Cítrico/análise , Citrus/química , Análise por Conglomerados , Análise Discriminante , Frutose/metabolismo , Glucose/metabolismo , Análise dos Mínimos Quadrados , México , Análise de Componente Principal
18.
Adv Exp Med Biol ; 1153: 91-100, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30701440

RESUMO

Inappropriate dietary habits influence the development of excessive body weight. The role of added sugars, including fructose, notably is significant in this process. It is estimated that fructose intake has increased many times over the past two centuries. The aim of the study was to define the effect of fructose consumption on anthropometric indices and lipid metabolism in obese (body mass index (BMI) >30 kg/m2) children and adolescents. The study included 84 patients (47 girls and 37 boys) aged 7-18 years, divided into prepubertal, pubertal, and post-pubertal age groups. Aside from BMI, the assessment comprised waist circumference, body composition estimated with bioelectrical impedance (BIA), plasma lipid profile, fructose intake consumption based on a 3-day menu analysis, and a number of calculated atherogenic indices. The major findings were that total daily fructose intake was high, on average, ranging from 19 to 26 g, with no appreciable relation to age. A higher fructose intake from beverages is significantly associated with the percentage of body fat, waist circumference, waist-to-height ratio, and also with the content of total cholesterol, triglycerides, and the level of atherogenic indices. In conclusion, fructose appears a particularly unfavorable component in children's diet as it is conducive to visceral obesity and atherogenic lipid profile. However, inadequate proportions of other macronutrients may also be at play in the development of metabolic diet-related disorders.


Assuntos
Frutose , Metabolismo dos Lipídeos , Obesidade , Adolescente , Índice de Massa Corporal , Criança , Feminino , Frutose/metabolismo , Humanos , Masculino , Obesidade/metabolismo , Circunferência da Cintura
19.
Bioresour Technol ; 278: 296-302, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30708333

RESUMO

Lactulose synthesis from fructose and lactose in continuous packed-bed reactor operation with glyoxyl-agarose immobilized Aspergillus oryzae ß-galactosidase is reported for the first time. Alternative strategies to conventional batch synthesis have been scarcely explored for lactulose synthesis. The effect of flow rate, substrates ratio and biocatalyst-inert packing material mass ratio (MB/MIM) were studied on reactor performance. Increase in any of these variables produced an increase in lactulose yield (YLu) being higher than obtained in batch synthesis at comparable conditions. Maximum YLu of 0.6 g·g-1 was obtained at 50 °C, pH 4.5, 50% w/w total sugars, 15 mL·min-1, fructose/lactose molar ratio of 12 and MB/MIM of 1/8 g·g-1; at such conditions yield of transgalactosylated oligosaccharides (YTOS) was 0.16 g·g-1, selectivity (lactulose/TOS molar ratio) was 5.4 and lactose conversion (XLactose) was 28%. Reactor operation with recycle had no significant effect on yield, producing only some decrease in productivity.


Assuntos
Aspergillus oryzae/enzimologia , Lactulose/biossíntese , beta-Galactosidase/metabolismo , Enzimas Imobilizadas/metabolismo , Frutose/metabolismo , Glioxilatos/metabolismo , Lactose/metabolismo , Oligossacarídeos/metabolismo , Sefarose/metabolismo
20.
Int J Biol Macromol ; 129: 31-40, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-30716378

RESUMO

A novel glucose isomerase gene from the thermophilic Caldicoprobacter algeriensis, encoding a polypeptide of 438 residues, was identified, cloned and successfully expressed in E. coli. The purified enzyme (GICA) was a homotetramer of about 200 kDa displaying the highest activity at pH 7.0 and 90 °C and retaining 97% of its maximum activity at pH 6.5. The enzyme showed an excellent thermostability with a half-life of 6 min at 100 °C. Interestingly, GICA had a very high affinity of 40 mM and catalytic efficiency of 194 min-1 mM-1 toward d-glucose at 90 °C. A maximum of 54.7% d-glucose to d-fructose conversion was achieved by GICA at 85 °C making it an attractive candidate for HFCS-55 production. The primary sequence inspection and molecular modeling studies revealed that the thermal stability of GICA could be attributed to the presence of extra charged residues at the surface like E108 and Q408 increasing surface charge interactions. Moreover, a serine at position 56 near to P58 could establish hydrogen bond strengthening the dimer attachment. The high catalytic efficiency and affinity of GICA could be ascribed to the presence of amino acid like E108 and K62 that created more charges around the catalytic site entry.


Assuntos
Aldose-Cetose Isomerases/química , Aldose-Cetose Isomerases/metabolismo , Bactérias/enzimologia , Termodinâmica , Aldose-Cetose Isomerases/genética , Sequência de Aminoácidos , Bactérias/classificação , Bactérias/genética , Fenômenos Químicos , Clonagem Molecular , Ativação Enzimática , Estabilidade Enzimática , Frutose/metabolismo , Expressão Gênica , Xarope de Milho Rico em Frutose/metabolismo , Concentração de Íons de Hidrogênio , Cinética , Modelos Moleculares , Conformação Molecular , Filogenia , Proteínas Recombinantes , Relação Estrutura-Atividade , Temperatura Ambiente
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