RESUMEN
The difference of metabolite profiles between raw and cooked pufferfish (Takifugu flavidus) meat was explored by 1H NMR technique and multivariate statistical methods. The orthogonal projection to latent structure-discriminant analysis (OPLS-DA) results showed an obvious separation between two samples. There were 24 dominating metabolites in the pufferfish muscle extraction, of which 11 metabolites changed significantly (pâ¯<â¯0.05), including 9 amino acids (alanine, leucine, methionine, tyrosine, glutamate, glycine, arginine, lysine, taurine), 1 organic acid (lactate) and 1 alkaloid (betaine). Moreover, the Student's t-test was performed to identify the different levels of metabolites. Sensory intensity experiments showed that there was a significant difference in the umami taste between raw and cooked pufferfish meat (pâ¯<â¯0.05). The content of glutamate, aspartate and 5'-IMP in the cooked meat increased, making the umami taste more intense. This study provided essential information about the metabolites explaining the taste difference between raw and cooked pufferfish meat.
Asunto(s)
Culinaria , Carne/análisis , Metabolómica , Takifugu , Aminoácidos/metabolismo , Animales , Espectroscopía de Resonancia Magnética , GustoRESUMEN
The potential health benefit of dietary fiber has attracted considerable attention in recent decades. In this study, the effects of modified dietary fibers (MDF) derived from okara on body composition, fat distribution, serum metabolomic parameters, and fatty acid profiles in mice fed high-fat diets (HFD) were evaluated by nuclear magnetic resonance (NMR)-based metabolic approach. HFD-induced C57BL mice were fed with a diet containing 100â¯g/kg MDF for 12â¯weeks. Compared with control mice, MDF-fed mice exhibited less fat and lower body weights, altered serum metabolomic profiles, and distinct fatty acid profiles. The levels of choline, phosphatidylcholine, glycerophosphorylcholine, glucose, lysine, scyllo-inositol, and glutamate for MDF group were higher than those for both CONT and HFD groups. A remarkable reduction of total cholesterol, total triglycerides, ω-6 fatty acids, alanine, citrate, creatine, or succinate was also observable for MDF group compared with HFD group. These findings demonstrated that the intake of MDF derived from okara clearly ameliorated some of the HFD-induced adverse metabolic effects and prevented adipose tissue accumulation.
Asunto(s)
Composición Corporal/efectos de los fármacos , Dieta Alta en Grasa/efectos adversos , Fibras de la Dieta/uso terapéutico , Ácidos Grasos/metabolismo , Tejido Adiposo/metabolismo , Alanina/sangre , Animales , Glucemia , Peso Corporal , Colesterol/sangre , Colina/sangre , Ácido Cítrico/sangre , Ácidos Grasos/sangre , Ácidos Grasos Omega-6/sangre , Ácido Glutámico/sangre , Glicerilfosforilcolina/sangre , Inositol/sangre , Lisina/sangre , Espectroscopía de Resonancia Magnética , Masculino , Metabolómica , Ratones , Ratones Endogámicos C57BL , Fosfatidilcolinas/sangre , Glycine max , Ácido Succínico/sangre , Triglicéridos/sangreRESUMEN
Exposure to PM2.5 is associated with an increased risk of lung diseases, and oxidative damage is the main reason for PM2.5-mediated lung injuries. However, little is known about the early molecular events in PM2.5-induced lung toxicity. In the present study, the metabolites in PM2.5-treated A549 cells were examined via a robust and nondestructive nuclear magnetic resonance (NMR)-based metabolic approach to clarify the molecular mechanism of PM2.5-induced toxicity. NMR analysis revealed that 12 metabolites were significantly altered in PM2.5-treated A549 cells, including up-regulation of alanine, valine, lactate, ω-6 fatty acids, and citrate and decreased levels of gamma-aminobutyric acid, acetate, leucine, isoleucine, D-glucose, lysine, and dimethylglycine. Pathway analysis demonstrated that seven metabolic pathways which included alanine, aspartate and glutamate metabolism, aminoacyl-tRNA biosynthesis, taurine and hypotaurine metabolism, arginine and proline metabolism, starch and sucrose metabolism, valine, leucine and isoleucine biosynthesis, and tricarboxylic acid cycle were mostly influenced. Our results indicate that NMR technique turns out to be a simple and reliable method for exploring the toxicity mechanism of air pollutant.
Asunto(s)
Contaminantes Atmosféricos/toxicidad , Redes y Vías Metabólicas/efectos de los fármacos , Material Particulado/toxicidad , Células A549 , Humanos , Pulmón , Imagen por Resonancia Magnética , Espectroscopía de Resonancia Magnética , Metabolómica/métodos , Taurina/análogos & derivados , ValinaRESUMEN
Natural phenazines are versatile secondary metabolites that are mainly produced by Pseudomonas and Streptomyces. All phenazine-type metabolites originate from two precursors: phenazine-1-carboxylic acid (PCA) in Pseudomonas or phenazine-1,6-dicarboxylic acid (PDC) in Streptomyces and other bacteria. Although the biosynthesis of PCA in Pseudomonas has been extensively studied, the origin of PDC still remains unclear. Comparing the phenazine biosynthesis operons of different species, we found that the phzA gene was restricted to Pseudomonas in which PCA is produced. By generating phzA-inactivated mutant, we found a new compound obviously accumulated; it was then isolated and identified as PDC. Protein sequence alignment showed that PhzA proteins from Pseudomonas form a separate group that is recognized by H73L and S77L mutations. Generating mutations of L73 into H73 and L77 into S77 resulted in a significant increase in PDC production. These findings suggest that phzA may act as a shunt switch of PDC biosynthesis in Pseudomonas and distinguish the pathway producing only PCA from the pathway forming PCA plus PDC. Using real-time PCR analysis, we suggested that the phzA, phzB, and phzG genes either directly or indirectly regulate the production of PDC, and phzA plays the most significant regulatory role. This is the first description of phzA in the biosynthesis of PDC, and the first-time substantial PDC was obtained in Pseudomonas. Therefore, this study not only provides valuable clues to better understand the biosynthesis of PCA and PDC in Pseudomonas but also introduces a method to produce PDC derivatives by genetically engineered strains.
Asunto(s)
Proteínas Bacterianas/genética , Genes Bacterianos , Fenazinas/metabolismo , Pseudomonas chlororaphis/genética , Secuencia de Aminoácidos , Proteínas Bacterianas/metabolismo , Fermentación , Eliminación de Gen , Espectroscopía de Resonancia Magnética , Espectrometría de Masas , Pseudomonas chlororaphis/metabolismo , Reacción en Cadena en Tiempo Real de la PolimerasaRESUMEN
This study investigated the in vitro anti-inflammatory and antioxidant properties, protein quality, and other related characteristics obtained by the single-cycle and two-cycle high hydrostatic pressure (HHP at 200, 400 and 600 MPa) treatment of squids (Todarodes pacificus). The soluble protein nitrogen content and in vitro protein digestibility increased significantly (p<0.05) after all HHP treatments, and the two-cycle 600 MPa HHP treatments yielded the highest values, 7.59% and 84.42%, respectively. The estimated protein efficiency ratios, and antioxidant and anti-inflammatory properties of squids significantly increased by all HHP treatments. (1)H nuclear magnetic resonance (NMR) showed that the main spectral changes associated to the anti-inflammatory properties of proteins following HHP treatment were in the range of 3.00-3.19 and 3.60-3.79 ppm. This indicates that the HHP treatments modified the protein and functional properties of squids and gave the relevant chemical shifts in NMR signals, either migrated or disappeared.
Asunto(s)
Antiinflamatorios , Antioxidantes , Decapodiformes/química , Proteínas Musculares , Animales , Antiinflamatorios/aislamiento & purificación , Antiinflamatorios/farmacología , Antioxidantes/aislamiento & purificación , Antioxidantes/farmacología , Compuestos de Bifenilo/química , Digestión/fisiología , Electroforesis en Gel de Poliacrilamida , Factor Estimulante de Colonias de Granulocitos y Macrófagos/análisis , Factor Estimulante de Colonias de Granulocitos y Macrófagos/inmunología , Presión Hidrostática , Modelos Biológicos , Proteínas Musculares/aislamiento & purificación , Proteínas Musculares/farmacología , Nitrógeno/análisis , Picratos/química , Factor de Necrosis Tumoral alfa/análisis , Factor de Necrosis Tumoral alfa/inmunologíaRESUMEN
Hydrophobic compounds with hydroxyl, aldehyde or ketone groups are generally difficult to detect using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), because these compounds have low proton affinity and are poorly ionized by MALDI. Herein, coumarins have been used as new matrices for MALDI-MS analysis of a variety of hydrophobic compounds with low ionization efficiency, including steroids, coenzyme Q10, a cyclic lipopeptide and cholesterol oleate. Five coumarins, including coumarin, umbelliferone, esculetin, 7-hydroxycoumarin-3-carboxylic acid (HCA) and 6,7-dihydroxycoumarin-3-carboxylic acid (DCA), were compared with the conventional matrices of 2,5-dihydroxybenzoic acid (DHB) and α-cyano-4-hydroxycinnamic acid (CHCA). Coumarins with hydroxyl or carboxylic acid groups enabled detection. Taking DCA as an example, this matrix proved to be superior to DHB or CHCA in detection sensitivity, stability, spot-to-spot and sample-to-sample reproducibility, and accuracy. DCA increased the stability of the target compounds and decreased the loss of water. The [M+Na](+) peaks were observed for all target compounds by adding NaCl as an additive, and the [M-H2O+H](+) and [M+H](+) peaks decreased. DCA was selected for the identification of sterols in yeast cells, and thirteen sterols were detected by Fourier transform ion cyclotron resonance (FT ICR) mass spectrometry. This work demonstrates the potential of DCA as a new matrix for detection of hydrophobic molecules by MALDI-MS and provides an alternative tool for screening sterols in antifungal research.
Asunto(s)
Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodos , Espectroscopía Infrarroja por Transformada de Fourier/métodos , Interacciones Hidrofóbicas e HidrofílicasRESUMEN
A novel hemicellulosic polysaccharide (ACAP) was purified from the cold alkali extraction of alfalfa stems and characterized as a heteroxylan with a weight-average molecular weight of 7.94 × 10(3) kDa and a radius of 58 nm. Structural analysis indicated that ACAP consisted of a 1,4-linked ß-D-Xylp backbone with 4-O-MeGlcpA and T-L-Araf substitutions at O-2 and O-3 positions, respectively. Transmission electron microscopy (TEM) examination revealed the entangled chain morphology of ACAP molecules. The evaluation of thermal degradation property revealed a primary decomposition temperature range of 238.8-314.0 °C with an apparent activation energy (Ea) and a pre-exponential factor (A) of 220.0 kJ/mol and 2.81 × 10(24)/s, respectively. ACAP also showed significant inhibitory activities on IL-1ß, IL-6, and COX-2 gene expressions in cultured RAW 264.7 mouse macrophage cells. These results suggested the potential utilization of ACAP in functional foods and dietary supplement products.
Asunto(s)
Antiinflamatorios/química , Antiinflamatorios/farmacología , Medicago sativa/química , Extractos Vegetales/química , Extractos Vegetales/farmacología , Polisacáridos/química , Polisacáridos/farmacología , Animales , Antiinflamatorios/aislamiento & purificación , Línea Celular , Estabilidad de Medicamentos , Calor , Interleucina-6/inmunología , Macrófagos/efectos de los fármacos , Macrófagos/inmunología , Ratones , Peso Molecular , Extractos Vegetales/aislamiento & purificación , Tallos de la Planta/química , Polisacáridos/aislamiento & purificaciónRESUMEN
A pectic polysaccharide (APPS) was purified from the cold alkali extract of alfalfa stem and characterized to be a rhamnogalacturonan I (RG-I) type pectin with the molecular weight of 2.38 × 10(3) kDa and a radius of 123 nm. The primary structural analysis indicated that APPS composed of a â2)-α-l-Rhap-(1â4)-α-d-GalpA-(1â backbone with 12% branching point at C-4 of Rhap forming side chains by l-arabinosyl and d-galactosyl oligosaccharide units. Transmission electron microscopy (TEM) analysis revealed a primary linear-shaped structure with a few branches in its assembly microstructures. The thermal decomposition evaluation revealed the stability of APPS with an apparent activation energy (Ea) of 226.5 kJ/mol and a pre-exponential factor (A) of 2.10 × 10(25)/s, whereas its primary degradation occurred in the temperature range from 215.6 to 328.0 °C. In addition, APPS showed significant anti-inflammatory effect against mRNA expressions of the pro-inflammatory cytokine genes, especially for IL-1ß, suggesting its potential utilization in functional foods and dietary supplement products.
Asunto(s)
Antiinflamatorios/química , Medicago sativa/química , Pectinas/química , Extractos Vegetales/química , Animales , Antiinflamatorios/farmacología , Línea Celular , Citocinas/genética , Calor , Macrófagos/efectos de los fármacos , Macrófagos/inmunología , Ratones , Peso Molecular , Pectinas/farmacología , Extractos Vegetales/farmacología , Tallos de la Planta/químicaRESUMEN
A novel microbial transglutaminase-catalyzed aqueous-organic biphasic reaction system was successfully developed to prepare caseinate derivatives by cross-linking and incorporating nonpolar octyl tails for the first time. SDS-PAGE and (1)H NMR analysis confirmed that cross-linking and octyl conjugation occurred simultaneously. The octyl substitution degree (SD) was measured by (1)H NMR and used as an index to determine a suitable reaction condition. It was found that at the condition of 0.125% (w/v) protein concentration and 6 h of reaction time, the modified caseinate had the highest SD of 28.96%. The modified caseinate also had an increased surface hydrophobicity, better emulsifying activity, and improved thermal and salt stabilities. However, its emulsion stability or in vitro enzymatic digestibility was slightly lower than that of the native caseinate.
Asunto(s)
Aminas/química , Proteínas Bacterianas/química , Caseínas/química , Reactivos de Enlaces Cruzados/química , Transglutaminasas/química , Biocatálisis , Streptomyces/enzimologíaRESUMEN
Many biopolymers assume ordered structure in solution due to specific intermolecular interactions, and subsequently aggregate to form fibrous network structures, which play important structural and functional roles both in biomedical tissues and in biopolymeric applied materials. In this study, the pulsed-field-gradient stimulated echo (PGSTE) (1)H NMR method was utilized to elucidate the gelation mechanism and to determine the network structure of agarose. The echo signal intensity of agarose decreased with the formation of aggregated bundles, and therefore, it was used to determine the concentration of the solute agarose (c(sol)) in the gel. The diffusion coefficient of a dendrimer, added to the gel as a probe molecule, increased concomitantly with the formation of the network of aggregated bundles, suggesting apparent dilution of solute agarose in the network interspaces. The hydrodynamic mesh size (ξ) of the network was estimated from the degree of retardation of the diffusion. The dependence of ξ on c(sol) was interpreted using a simple model, where the hydrodynamic interaction of the probe molecule with a solute chain or an aggregated bundle of chains is same. Our theoretically predicted lines fitted well on the experimentally obtained plots, thus validating the use of this model.