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1.
Food Chem ; 332: 127387, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32629331

RESUMO

The simultaneous formation of acrylamide; ß-carboline heterocyclic amines (HAs): harmane and norharmane; and advanced glycation end products (AGEs) (Nε-(carboxymethyl)lysine (CML) and Nε-(carboxyethyl)lysine (CEL)) was analyzed based on an aqueous model system. The model systems included lysine-glucose (Lys/Glu), asparagine-glucose (Asn/Glu), tryptophan-glucose (Trp/Glu), and a mixture of these amino acids (Mix/Glu). Only AGEs were generated when heated at 100 °C, Asn and Trp competed with Lys for glucose and methylglyoxal (MGO), and glyoxal (GO) decreased AGE content. The k value of CML, CEL, and acrylamide decreased when heated at 130 °C, whereas that of harmane increased in the Mix/Glu, owing to the competition between Lys and Asn for glucose, GO, and MGO. Harmane preferably formed via the Pictet-Spengler condensation between Trp and acetaldehyde, which further reduced acrylamide formation via the acrolein pathway.


Assuntos
Acrilamida/análise , Aminas/análise , Produtos Finais de Glicação Avançada/análise , Reação de Maillard , Asparagina/química , Carbolinas/análise , Carbolinas/química , Cromatografia Gasosa , Cromatografia Líquida de Alta Pressão , Glucose/química , Harmina/análogos & derivados , Harmina/análise , Harmina/metabolismo , Temperatura Alta , Lisina/análogos & derivados , Lisina/análise , Modelos Biológicos , Aldeído Pirúvico/química
2.
Food Chem ; 329: 127085, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32512390

RESUMO

The refractive index is a basic optical property of materials. This study explores the effect of ethanol, glycerol, tartaric acid and glucose/fructose on the refractive index in model aqueous solutions and in dry white wines. Various model aqueous solutions consisting of these components were prepared and the refractive index was measured at 20 °C and each component was studied both alone and in mixtures with the others. The refractive index of white dry wines samples was also measured. A linear regression analysis was performed and linear multi-dependence equations were derived. The resulting regression models had a coefficient of determination over 97.3%. Glucose/fructose was found to have the greatest effect on the refractive index, followed by tartaric acid and glycerol while ethanol had the smallest effect. The knowledge of the correlation of the concentration of each wine component to the refractive index can be of value for the estimation of fermentation kinetics.


Assuntos
Etanol/química , Frutose/química , Glucose/química , Glicerol/química , Tartaratos/química , Água/química , Vinho/análise , Refratometria
3.
Food Chem ; 328: 127099, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-32474238

RESUMO

In this study, we developed a competitive colorimetric immunoassay for qualitative detection of DAN based on oxidation of iron (Ⅱ) (Fe2+) in the presence of glucose oxidase (GOx) and color change induced by Fe2+-phenanthroline (Phen) chromogenic system. Streptavidin (SA) acted as a linker between biotinylated anti-DAN-monoantibody (bio-mAb) and biotinylated GOx (bio-GOx) to form the immunocomplexes bio-mAb-SA-bio-GOx. In the absence of DAN, the immunocomplexes bio-mAb-SA-bio-GOx combining with coated DAN-ovalbumin (DAN-OVA) will be immobilized and catalyze glucose to produce H2O2. Fe2+ is oxidized to Fe3+ by H2O2, giving rise to a colorless result. In the presence of DAN, Fe2+ produces a chelation reaction with Phen, leading to orange-red color. Under optimal conditions, the detection limit (LOD) by naked eyes was 2.5 ng mL-1 in milk, chicken, beef, and pork samples. Low LOD, no matrix effect, and no signal reader requirement make it possibly applied to quickly screen DAN on site.


Assuntos
Técnicas Biossensoriais/métodos , Colorimetria/métodos , Fluoroquinolonas/análise , Glucose Oxidase/metabolismo , Imunoensaio/métodos , Quelantes de Ferro/química , Fenantrolinas/química , Biocatálise , Catálise , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Fluoroquinolonas/química , Glucose/química , Glucose Oxidase/química , Peróxido de Hidrogênio/química , Limite de Detecção
4.
Nat Commun ; 11(1): 3083, 2020 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-32576828

RESUMO

Short-term fasting protects tumor-bearing mice against the toxic effects of chemotherapy while enhancing therapeutic efficacy. We randomized 131 patients with HER2-negative stage II/III breast cancer, without diabetes and a BMI over 18 kg m-2, to receive either a fasting mimicking diet (FMD) or their regular diet for 3 days prior to and during neoadjuvant chemotherapy. Here we show that there was no difference in toxicity between both groups, despite the fact that dexamethasone was omitted in the FMD group. A radiologically complete or partial response occurs more often in patients using the FMD (OR 3.168, P = 0.039). Moreover, per-protocol analysis reveals that the Miller&Payne 4/5 pathological response, indicating 90-100% tumor-cell loss, is more likely to occur in patients using the FMD (OR 4.109, P = 0.016). Also, the FMD significantly curtails chemotherapy-induced DNA damage in T-lymphocytes. These positive findings encourage further exploration of the benefits of fasting/FMD in cancer therapy. Trial number: NCT02126449.


Assuntos
Neoplasias da Mama/dietoterapia , Neoplasias da Mama/tratamento farmacológico , Dieta , Jejum , Adulto , Idoso , Animais , Índice de Massa Corporal , Quimioterapia Adjuvante , Dano ao DNA , Dexametasona/uso terapêutico , Feminino , Glucose/química , Humanos , Análise de Intenção de Tratamento , Menopausa , Camundongos , Pessoa de Meia-Idade , Terapia Neoadjuvante , Países Baixos , Qualidade de Vida , Receptor ErbB-2/metabolismo , Linfócitos T/citologia , Linfócitos T/imunologia
5.
Food Chem ; 328: 127122, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-32480260

RESUMO

Glycation between target proteins and saccharides is time-consuming or requires high temperatures. Here, a promising reaction medium, natural deep eutectic solvents (NADES), for glucose glycation with bovine serum albumin (BSA) was applied to improve the grafting of glucose-glycated BSA by shifting reaction equilibrium. Two types of glucose-glycated BSA products were prepared using NADES and water systems. SDS-PAGE and MALDI-TOF-MS revealed that BSA and glucose were covalently bonded. Compared with in water system, glycated BSA products in NADES system had more -OH groups, more disordered secondary structures, lower intrinsic fluorescence intensity, and higher ultraviolet-visible absorption. Lower surface hydrophobicity (1100 versus 1356), higher emulsifying activity index (66.17 versus 46.49 m2/g), higher emulsion stability index (79.62 versus 63.61%), and lesser free sulfhydryl (8.07 versus 8.98 µmol/g) groups were obtained with NADES system than with water system. The results suggest that NADES is a suitable alternative reaction medium for promoting the glycation of BSA.


Assuntos
Glucose/química , Soroalbumina Bovina/química , Animais , Glicosilação , Interações Hidrofóbicas e Hidrofílicas , Solventes/química
6.
Food Chem ; 330: 127170, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32531633

RESUMO

With the increasing concerns on food safety, foodborne toxicants, particularly advanced glycation end products (AGEs) have drawn large attention ascribing to their central role in the pathogenic process of diabetic complications. In this study, the antiglycative ability and action mechanism of 10 dried flowers were measured in fructose/glucose-BSA model with apple flower as the most effective one, probably through trapping reactive carbonyl species. Furthermore, apple flower was added in cookies to evaluate its antiglycative effect and data suggested that the fortification of cookies with apple flower powders significantly inhibited the formation of methylglyoxal and fluorescent AGEs. Moreover, sensory evaluation data showed that 2.5% (w/w) apple flower-fortified cookies had the highest acceptance. The active component in apple flower was further identified as phlorizin by chromatographic analysis. Our results highlighted the health benefits of consuming apple flower fortified foods which might possibly be developed into functional foods especially for diabetic patients.


Assuntos
Frutose/química , Glucose/química , Produtos Finais de Glicação Avançada/química , Malus/química , Animais , Flores/química , Aldeído Pirúvico/química , Soroalbumina Bovina/química
7.
Food Chem ; 329: 127160, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32485646

RESUMO

In this study, we developed an indirect competitive plasmonic immunoassay using glucose oxidase (GOx)-induced redox reaction to etch Au nanorods (AuNRs) for qualitative and quantitative detection of aflatoxin M1 (AFM1) in milk. In this system, streptavidin (SA) was selected as a linker between biotinylated anti-AFM1-monoantibody (bio-mAb) and biotinylated GOx (bio-GOx) to form the immunocomplexes bio-mAb-SA-bio-GOx. After the oxidation of the glucose and I-, the resultant I2 could etch cetytrimethylammonium bromide (CTAB)-stabilized AuNRs. This resulted in the blue shift of the longitudinal localized surface plasmon resonance (LSPR) extinction peak, with a color change from blue to pink. The linear range and limit of detection (LOD) of the plasmonic immunoassay were 0.25-10 ng mL-1 and 0.11 ng mL-1, respectively. It displayed quantitative detection with high sensitivity, specificity, recovery, and accuracy, which is promising for qualitative and quantitative detection of AFM1 in food safety.


Assuntos
Aflatoxina M1/análise , Contaminação de Alimentos/análise , Imunoensaio/métodos , Leite/química , Nanotubos , Animais , Glucose/química , Glucose Oxidase/química , Ouro/química , Imunoensaio/instrumentação , Limite de Detecção , Nanotubos/química , Sensibilidade e Especificidade , Ressonância de Plasmônio de Superfície/métodos
8.
Food Chem ; 329: 127171, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32502745

RESUMO

The inhibition effects of glutathione (GSH) on acrylamide (AA) in the asparagine/glucose model systems and cookies were investigated. The formation of AA was significantly inhibited by GSH addition in the model systems. The decreasing levels of AA were in the range of 38-86%, 57-82%, and 3-41% at 120, 140, and 160 °C, respectively. In addition, the presence of GSH in cookies also inhibited the AA formation, but with no corresponding relationship between the GSH level and the inhibition ratio. The addition of 0.05 g/kg GSH in cookie dough resulted in the decreasing of AA by 48%, some improvement in cookie lightness, but no influence on cookie texture. Kinetic analysis showed that the application of GSH not only inhibited the formation of AA but also improved the elimination of AA. In the summary, GSH could be a potential inhibitor to reduce the AA formation in food during the heating process.


Assuntos
Acrilamida/química , Asparagina/química , Culinária , Glucose/química , Glutationa/química , Acrilamida/metabolismo , Asparagina/metabolismo , Indústria de Processamento de Alimentos , Glucose/metabolismo , Glutationa/metabolismo , Cinética
9.
Nat Commun ; 11(1): 2664, 2020 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-32471982

RESUMO

Controlling the chemical glycosylation reaction remains the major challenge in the synthesis of oligosaccharides. Though 1,2-trans glycosidic linkages can be installed using neighboring group participation, the construction of 1,2-cis linkages is difficult and has no general solution. Long-range participation (LRP) by distal acyl groups may steer the stereoselectivity, but contradictory results have been reported on the role and strength of this stereoelectronic effect. It has been exceedingly difficult to study the bridging dioxolenium ion intermediates because of their high reactivity and fleeting nature. Here we report an integrated approach, using infrared ion spectroscopy, DFT computations, and a systematic series of glycosylation reactions to probe these ions in detail. Our study reveals how distal acyl groups can play a decisive role in shaping the stereochemical outcome of a glycosylation reaction, and opens new avenues to exploit these species in the assembly of oligosaccharides and glycoconjugates to fuel biological research.


Assuntos
Química Computacional/métodos , Oligossacarídeos/síntese química , Compostos de Selênio/química , Configuração de Carboidratos , Galactose/química , Glucose/química , Glicosilação , Manose/química , Espectrofotometria Infravermelho
10.
Food Chem ; 327: 127054, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32460129

RESUMO

Interactions between saccharides and ions in aqueous solutions are of great importance in many fields (chemistry, physico-chemistry, biology, food industries). Thus, this work proposes to develop a methodology dealing with the characterization and the understanding of interactions between saccharides and cations in presence of water molecules, by a quantum mechanics approach. In the first part, the saccharide hydration properties (xylose, glucose, sucrose) in pure water are determined. Results show that the saccharide coordination numbers, as well as the saccharides hydration enthalpy, increase with the saccharide hydrophilic group number. In the second part, the influence of cations on saccharides hydration properties, and inversely, is evaluated. In saccharide/cation/water systems, the decrease in hydration enthalpy of cations and saccharides shows that both species are dehydrated and that saccharide dehydration depends on the nature of the cation. The dehydration sequence of saccharides was explained from the study of saccharide/cation interactions.


Assuntos
Carboidratos/química , Teoria da Densidade Funcional , Água/química , Cátions/química , Glucose/química , Interações Hidrofóbicas e Hidrofílicas , Metais/química , Sacarose/química , Termodinâmica , Xilose/química
11.
Food Chem ; 326: 126982, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32413762

RESUMO

Glutathione (GSH) is a potential inhibitor for acrylamide (AA) in heated food. In the present study, the inhibition pathways of GSH on AA were investigated in the asparagine(Asn)/glucose(Glc)/GSH model system. In comparison to the Asn/Glc model system, three unique molecular ions (m/z 470, 379, and 193) were identified in the Asn/Glc/GSH model system. Those molecular ions were confirmed as the Amadori rearrangement products which formed in the reaction between Glc and GSH, as well as the addition reaction products between AA and the sulfhydryl group (-SH) of GSH and cysteine (Cys). The competition between Asn and GSH for Glc in the competitive reactions was assumed to be the major pathway. Additionally, the elimination reaction between AA and GSH or between AA and Cys also played a minor role in the inhibition of AA. The variances of precursors, intermediates, and final products provided quantitative evidence for the above pathways.


Assuntos
Acrilamida/antagonistas & inibidores , Glutationa/química , Acrilamida/metabolismo , Asparagina/química , Glucose/química , Glutationa/metabolismo , Compostos de Sulfidrila/química , Espectrometria de Massas em Tandem , Temperatura
12.
Food Chem ; 326: 126981, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32416420

RESUMO

Water activity is a physical property measured in the food industry which helps predict shelf life and microbial activity. Honey normally has a water activity less than 0.6, but this can vary with the amount of crystallization in solution. The aim of this work was to obtain relationships, as fundamental as possible, that can be used to predict the water activity of solutions with compositions similar to honey. Water activity measurements of aqueous sucrose solutions have been well analysed in literature using hydration theory. The analysis based on hydration numbers was easily able to show the quality of data previously published, and hence relationships were proposed for the hydration numbers of glucose, fructose, maltose and glycerol. A model was proposed in this study, to predict the water activity of food systems containing high concentrations of sugars and some electrolytes. The model was analysed and validated using mostly literature data supplemented with new experimental data.


Assuntos
Mel/análise , Soluções/química , Açúcares/química , Água/química , Cristalização , Eletrólitos/química , Glucose/química , Maltose/química , Modelos Teóricos , Sacarose/química
13.
PLoS One ; 15(5): e0232851, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32392238

RESUMO

Here we present the synthesis and characterization of two new conducting materials having a high electro-chemo-mechanical activity for possible applications as artificial muscles or soft smart actuators in biomimetic structures. Glucose-gelatin nanofiber scaffolds (CFS) were coated with polypyrrole (PPy) first by chemical polymerization followed by electrochemical polymerization doped with dodecylbenzensulfonate (DBS-) forming CFS-PPy/DBS films, or with trifluoromethanesulfonate (CF3SO3-, TF) giving CFS-PPy/TF films. The composition, electronic and ionic conductivity of the materials were determined using different techniques. The electro-chemo-mechanical characterization of the films was carried out by cyclic voltammetry and square wave potential steps in bis(trifluoromethane)sulfonimide lithium solutions of propylene carbonate (LiTFSI-PC). Linear actuation of the CFS-PPy/DBS material exhibited 20% of strain variation with a stress of 0.14 MPa, rather similar to skeletal muscles. After 1000 cycles, the creeping effect was as low as 0,2% having a good long-term stability showing a strain variation per cycle of -1.8% (after 1000 cycles). Those material properties are excellent for future technological applications as artificial muscles, batteries, smart membranes, and so on.


Assuntos
Órgãos Artificiais , Materiais Biomiméticos , Materiais Revestidos Biocompatíveis/química , Nanofibras , Polímeros/química , Pirróis/química , Tecidos Suporte , Benzenossulfonatos/química , Condutividade Elétrica , Eletroquímica , Gelatina/química , Glucose/química , Mesilatos/química , Microscopia Eletrônica de Varredura , Músculos , Nanofibras/química , Nanofibras/ultraestrutura , Polimerização , Potenciometria , Espectrometria por Raios X , Espectroscopia de Infravermelho com Transformada de Fourier , Estresse Mecânico , Propriedades de Superfície , Tecidos Suporte/química
14.
Nature ; 580(7804): 511-516, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32322067

RESUMO

The taste of sugar is one of the most basic sensory percepts for humans and other animals. Animals can develop a strong preference for sugar even if they lack sweet taste receptors, indicating a mechanism independent of taste1-3. Here we examined the neural basis for sugar preference and demonstrate that a population of neurons in the vagal ganglia and brainstem are activated via the gut-brain axis to create preference for sugar. These neurons are stimulated in response to sugar but not artificial sweeteners, and are activated by direct delivery of sugar to the gut. Using functional imaging we monitored activity of the gut-brain axis, and identified the vagal neurons activated by intestinal delivery of glucose. Next, we engineered mice in which synaptic activity in this gut-to-brain circuit was genetically silenced, and prevented the development of behavioural preference for sugar. Moreover, we show that co-opting this circuit by chemogenetic activation can create preferences to otherwise less-preferred stimuli. Together, these findings reveal a gut-to-brain post-ingestive sugar-sensing pathway critical for the development of sugar preference. In addition, they explain the neural basis for differences in the behavioural effects of sweeteners versus sugar, and uncover an essential circuit underlying the highly appetitive effects of sugar.


Assuntos
Encéfalo/fisiologia , Comportamento de Escolha/fisiologia , Açúcares da Dieta/metabolismo , Preferências Alimentares/fisiologia , Glucose/metabolismo , Intestinos/fisiologia , Animais , Encéfalo/citologia , Açúcares da Dieta/química , Glucose/análogos & derivados , Glucose/química , Masculino , Metilglucosídeos/química , Metilglucosídeos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Neurônios/fisiologia , Paladar/fisiologia , Tiazinas/metabolismo , Água/metabolismo
15.
J Med Chem ; 63(10): 5442-5457, 2020 05 28.
Artigo em Inglês | MEDLINE | ID: mdl-32286062

RESUMO

Chiral sugar derivatives are potential cyclitol surrogates of the Ca2+-mobilizing intracellular messenger d-myo-inositol 1,4,5-trisphosphate [Ins(1,4,5)P3]. Six novel polyphosphorylated analogues derived from both d- and l-glucose were synthesized. Binding to Ins(1,4,5)P3 receptors [Ins(1,4,5)P3R] and the ability to release Ca2+ from intracellular stores via type 1 Ins(1,4,5)P3Rs were investigated. ß-d-Glucopyranosyl 1,3,4-tris-phosphate, with similar phosphate regiochemistry and stereochemistry to Ins(1,4,5)P3, and α-d-glucopyranosyl 1,3,4-tris-phosphate are full agonists, being equipotent and 23-fold less potent than Ins(1,4,5)P3, respectively, in Ca2+-release assays and similar to Ins(1,4,5)P3 and 15-fold weaker in binding assays. They can be viewed as truncated analogues of adenophostin A and refine understanding of structure-activity relationships for this Ins(1,4,5)P3R agonist. l-Glucose-derived ligands, methyl α-l-glucopyranoside 2,3,6-trisphosphate and methyl α-l-glucopyranoside 2,4,6-trisphosphate, are also active, while their corresponding d-enantiomers, methyl α-d-glucopyranoside 2,3,6-trisphosphate and methyl α-d-glucopyranoside 2,4,6-trisphosphate, are inactive. Interestingly, both l-glucose-derived ligands are partial agonists: they are among the least efficacious agonists of Ins(1,4,5)P3R yet identified, providing new leads for antagonist development.


Assuntos
Agonismo Parcial de Drogas , Glucose/química , Receptores de Inositol 1,4,5-Trifosfato/agonistas , Receptores de Inositol 1,4,5-Trifosfato/química , Inositol 1,4,5-Trifosfato/química , Mimetismo Molecular/efeitos dos fármacos , Polifosfatos/química , Animais , Relação Dose-Resposta a Droga , Glucose/farmacologia , Células HEK293 , Humanos , Inositol 1,4,5-Trifosfato/farmacologia , Simulação de Acoplamento Molecular/métodos , Mimetismo Molecular/fisiologia , Polifosfatos/farmacologia , Estrutura Secundária de Proteína , Ratos , Ratos Wistar
16.
Transfusion ; 60(5): 1042-1049, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32187700

RESUMO

BACKGROUND: Some jurisdictions require leukoreduction of cellular blood components. The only whole blood collection set with a platelet-saving filter uses citrate-phosphate-dextrose (CPD) as storage solution. Substituting CPD with citrate-phosphate-dextrose-adenine (CPDA-1) increases shelf life from 21 to 35 days. This would simplify prehospital and rural resupply and reduce wastage. We investigated in vitro quality and hemostatic properties of CPDA-1 whole blood leukoreduced with a platelet-saving filter. STUDY DESIGN AND METHODS: CPDA-1 whole blood was leukoreduced using a platelet-saving filter and stored 35 days. EDQM requirements, hematology, metabolic parameters, thromboelastography, light transmission aggregometry, fibrinogen, factor VIII, and interleukin-6 were measured on Days 0, 1, 14, 21, and 35 and compared to non-leukoreduced blood. RESULTS: All units met EDQM requirements. Leukoreduction yielded residual white blood cell count <1 × 106 and 87% platelet recovery on Day 1. It caused reduction in thromboelastography parameters, but not aggregometry response. No hemolysis >0.8% was observed. Factor VIII was higher on Day 35 in the leukoreduced group, 37.9 (95% CI: 26.0, 49.8) versus 13.8 (9.4, 18.2) IU/dL. In both groups, aggregation was significantly reduced by Day 14. Thromboelastography showed remaining platelet activity on Day 35, MA 46.9 (42.1, 51.7) in the leukoreduced and 44.3 (39.6, 49.0) mm in the non-leukoreduced group. Fibrinogen was within reference ranges at Day 35 (>2 g/dL). Interleukin-6 was not detectable. CONCLUSION: Leukoreducing CPDA-1 whole blood with a platelet-saving filter did not compromise hemostatic properties. We encourage development of a single bag CPDA-1 whole blood collection set with in-line platelet-saving filter.


Assuntos
Adenina/química , Preservação de Sangue/métodos , Coleta de Amostras Sanguíneas/métodos , Citratos/química , Temperatura Baixa , Glucose/química , Procedimentos de Redução de Leucócitos/métodos , Fosfatos/química , Adenina/farmacologia , Sangue/efeitos dos fármacos , Plaquetas/citologia , Plaquetas/efeitos dos fármacos , Preservação de Sangue/normas , Coleta de Amostras Sanguíneas/normas , Citratos/farmacologia , Filtração/métodos , Glucose/farmacologia , Hemólise/efeitos dos fármacos , Hemostasia/efeitos dos fármacos , Humanos , Técnicas In Vitro , Procedimentos de Redução de Leucócitos/normas , Fosfatos/farmacologia , Agregação Plaquetária/efeitos dos fármacos , Contagem de Plaquetas , Controle de Qualidade , Refrigeração/métodos
17.
Chemistry ; 26(40): 8714-8719, 2020 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-32134164

RESUMO

In the development of colorimetric biosensors, the use of electrochromic mediators has been accepted and widely used during decades. The main drawback of these types of enzymatic substrates is the difficult recovery of the initial redox state of the molecule, which can be done electrochemically or by antioxidants addition, complicating the initially simple structure of the biosensor. those strategies are rarely followed Actually, being the disposable biosensor configuration the most extended for this detection mechanisms. Alternatively, we propose the first reported use of a diacid dithienylethene 1,2-bis(5-carboxy-2-methylthien-3-yl)cyclopentene (DTE) photoelectrochromic compound as a substrate of the horseradish peroxidase (HRP). The photoisomerization between the open (DTEo) and closed (DTEc) forms of the molecule and the respective shift in the redox potential allowed the light-induced enzymatic detection of glucose in the glucose oxidase [(GOx)]-HRP cascade system. This fast and easy control over the enzymatic substrate availability by light pulses permits a gradually consumption and the light-regeneration of the biosensor for a number of cycles. We consider the presented results transcendent in the development of reusable and light-controlled photonic biosensing systems.


Assuntos
Glucose Oxidase/metabolismo , Glucose/química , Peroxidase do Rábano Silvestre/metabolismo , Técnicas Biossensoriais/métodos , Colorimetria/métodos , Glucose Oxidase/química , Peroxidase do Rábano Silvestre/química , Oxirredução
18.
Yakugaku Zasshi ; 140(3): 329-344, 2020.
Artigo em Japonês | MEDLINE | ID: mdl-32115550

RESUMO

I have engaged in medicinal chemical studies based on the theoretical design of bioactive compounds. First, I present a three-dimensional structural diversity-oriented conformational restriction strategy for developing bioactive compounds based on the characteristic steric and stereoelectronic features of cyclopropane. Using this strategy, various biologically active small molecule compounds, such as receptor agonists/antagonists and enzyme inhibitors, were effectively developed. The strategy was also applied to develop versatile peptidomimetics and membrane-permeable cyclic peptides. Next, studies on Ca2+-mobilizing second messengers, cyclic ADP-ribose (cADPR) and myo-inositol trisphosphates (IP3), are described. In these studies, stable equivalents of cADPR were developed, since biological studies of cADPR have been limited due to its instability. Various potent IP3 receptor ligands, which were designed using the d-glucose structure as a bioisostere of the myo-inositol moiety of IP3, have been identified. Organic chemistry studies have also been extensively performed, because excellent organic chemistry is essential for promoting high-level medicinal chemical studies. For examples, new methods for the synthesis of chiral cyclopropanes, new radical reactions with silicon tethers, and kinetic anomeric effect-dependent stereoselective glycosidations have been developed.


Assuntos
ADP-Ribose Cíclica/química , Ciclopropanos/química , Desenho de Fármacos , Desenvolvimento de Medicamentos , Inositol 1,4,5-Trifosfato/química , Cálcio/metabolismo , Ciclopropanos/síntese química , Inibidores Enzimáticos , Glucose/química , Ligantes , Conformação Molecular , Fenômenos de Química Orgânica , Peptídeos Cíclicos/química , Peptidomiméticos , Estereoisomerismo
19.
Food Chem ; 318: 126467, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32145542

RESUMO

This study aims to investigate in depth the mechanism of acrylamide formation in coffee during roasting. For this purpose, a comprehensive kinetic model including the elementary steps for acrylamide formation was proposed. The changes in sucrose, reducing sugars, free amino acids, asparagine, acrylamide, 3-deoxyglucosone, methylglyoxal, glyoxal, and 5-hydroxymethylfurfural were monitored in coffee during roasting at 200, 220 and 240 °C. Dominant pathways of complex reactions leading to acrylamide were unravelled by means of multiresponse kinetic modelling approach. The results of the model indicated that sucrose degrades into glucose and a reactive fructofuranosyl cation. Interestingly, glucose takes part mostly in the formation of intermediates, glyoxal and especially 3-deoxyglucosone rather than acrylamide formation. On the other hand, fructofuranosyl cation contributed mostly to the formation of 5-hydroxymethylfurfural which was found to be the most important intermediate precursor of acrylamide formed in coffee during roasting.


Assuntos
Acrilamida/química , Café/química , Furaldeído/análogos & derivados , Aminoácidos/química , Desoxiglucose/análogos & derivados , Desoxiglucose/química , Indústria de Processamento de Alimentos/métodos , Furaldeído/química , Glucose/química , Glioxal/química , Temperatura Alta , Cinética , Aldeído Pirúvico/química , Sacarose/química
20.
PLoS One ; 15(3): e0229990, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32163461

RESUMO

A method was developed and validated for low-level detection of glucose. The method involves quantitation of glucose though derivitization with 1-phenyl-3-methyl-5-pyrazolone (PMP) and HPLC-DAD analysis. The developed method was found to be accurate and robust achieving detection limits as low as 0.09 nM. The applicability of the method was tested against microbial samples with glucose acting as a carbon fuel source. The method was shown to be able to accurately discriminate and quantify PMP-glucose derivatives within Shewanella oneidensis MR-1 samples. The method proved capable at examining glucose usage during the early hours of microbial growth, with detectable usage occurring as early as two hours. S. oneidensis cultures were found to grow more effectively in the presence of oxygen which coincided with more efficient glucose usage. Glucose usage further increased in the presence of competing electron acceptors. The rate at which S. oneidensis reached exponential growth was affected by the presence of ferric iron under microaerobic conditions. Such samples reached exponential growth approximately two hours sooner than aerobic samples.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Edaravone/química , Glucose/análise , Shewanella/metabolismo , Cromatografia de Fase Reversa , Compostos Férricos/química , Glucose/química , Limite de Detecção , Reprodutibilidade dos Testes , Shewanella/crescimento & desenvolvimento
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