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1.
J Agric Food Chem ; 67(38): 10702-10712, 2019 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-31490688

RESUMO

Human milk oligosaccharides are complex carbohydrates with multibiofunctional health benefits to newborns. Human milk free oligosaccharides (HMOs) are well characterized. However, changes in the N/O-glycome during lactation are poorly reported. Herein, we qualitatively and quantitatively investigated N/O-glycome profiles and their alteration in human milk at different lactation stages. N-Glycans were mainly fucosylated and nonsialylated, nonfucosylated throughout lactation. O-Glycans mainly consisted of sialylated and nonsialylated, nonfucosylated in colostrum and transitional milk, and fucosylated and nonfucosylated, nonsialylated in mature milk. Fucosylated and sialylated N-glycans gradually decreased and increased, respectively, as lactation progressed; O-glycans showed the reverse. Interestingly, changes in HMO abundance decreased during lactation, complementing HMG N/O-glycome changes. In conclusion, temporal HMG glycosylation changes provide the groundwork for developing infant formula that is closer to breast milk at different lactation stages.


Assuntos
Glicoproteínas/química , Lactação , Leite Humano/química , Adulto , Colostro/química , Feminino , Glicoproteínas/metabolismo , Glicosilação , Humanos , Espectrometria de Massas , Leite Humano/metabolismo , Oligossacarídeos/química , Oligossacarídeos/metabolismo , Polissacarídeos/química , Polissacarídeos/metabolismo
2.
Microb Cell Fact ; 18(1): 159, 2019 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-31542050

RESUMO

BACKGROUND: Xylanases randomly cleave the internal ß-1,4-glycosidic bonds in the xylan backbone and are grouped into different families in the carbohydrate-active enzyme (CAZy) database. Although multiple xylanases are detected in single strains of many filamentous fungi, no study has been reported on the composition, synergistic effect, and mode of action in a complete set of xylanases secreted by the same microorganism. RESULTS: All three xylanases secreted by Penicillium chrysogenum P33 were expressed and characterized. The enzymes Xyl1 and Xyl3 belong to the GH10 family and Xyl3 contains a CBM1 domain at its C-terminal, whereas Xyl2 belongs to the GH11 family. The optimal temperature/pH values were 35 °C/6.0, 50 °C/5.0 and 55 °C/6.0 for Xyl1, Xyl2, and Xyl3, respectively. The three xylanases exhibited synergistic effects, with the maximum synergy observed between Xyl3 and Xyl2, which are from different families. The synergy between xylanases could also improve the hydrolysis of cellulase (C), with the maximum amount of reducing sugars (5.68 mg/mL) observed using the combination of C + Xyl2 + Xyl3. Although the enzymatic activity of Xyl1 toward xylan was low, it was shown to be capable of hydrolyzing xylooligosaccharides into xylose. Xyl2 was shown to hydrolyze xylan to long-chain xylooligosaccharides, whereas Xyl3 hydrolyzed xylan to xylooligosaccharides with a lower degree of polymerization. CONCLUSIONS: Synergistic effect exists among different xylanases, and it was higher between xylanases from different families. The cooperation of hydrolysis modes comprised the primary mechanism for the observed synergy between different xylanases. This study demonstrated, for the first time, that the hydrolysates of GH11 xylanases can be further hydrolyzed by GH10 xylanases, but not vice versa.


Assuntos
Endo-1,4-beta-Xilanases/metabolismo , Proteínas Fúngicas/metabolismo , Penicillium chrysogenum/enzimologia , Polissacarídeos/metabolismo , Biocatálise , Endo-1,4-beta-Xilanases/química , Endo-1,4-beta-Xilanases/genética , Estabilidade Enzimática , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Glucuronatos/metabolismo , Temperatura Alta , Hidrólise , Família Multigênica , Oligossacarídeos/metabolismo , Penicillium chrysogenum/química , Penicillium chrysogenum/genética , Domínios Proteicos , Xilanos/metabolismo
3.
Bioresour Technol ; 289: 121700, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31262543

RESUMO

There is a growing interest in developing bio-based biodegradable plastics to reduce the dependence on depleting fossil fuels and provide a sustainable alternative. Bio-based plastics can usually be produced from lipids, proteins or carbohydrates, which are major components of microalgae. Despite its potential for algal plastics, little information is available on strain selection, culture optimization and bioplastics fabrication mechanism. In this review, we summarized the recent developments in understanding the utilization of seaweed polysaccharides, such as alginate and carrageenan for bio-based plastics. In addition, a conceptual biorefinery framework for algal plastics through promising components (e.g., lipids, carbohydrates and proteins) from microalgae is comprehensively presented. Moreover, the reasons for variations in bioplastics performance and underlying mechanism of various algal biocomposites have been critically discussed. We believe this review can provide valuable information to accelerate the development of innovative green technologies for improving the commercial viability of algal plastics.


Assuntos
Plásticos Biodegradáveis/metabolismo , Microalgas/metabolismo , Combustíveis Fósseis , Polissacarídeos/metabolismo
4.
Bioresour Technol ; 289: 121693, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31260934

RESUMO

The optimum condition of steam explosion pretreatment was screened for hippophae, and anaerobic calcium oxide (CaO) alkalization was further used to improve its enzymatic hydrolysis. Steam-exploded hippophae reached the lowest pH value (4.01) and the maximal hemicellulose removal (77.16%) at pressure 1.5 MPa and residence time 20 min. Lignocellulosic fractions of hippophae was remarkably reduced by CaO alkalization or steam explosion treatment, and enzymatic sugar yield was increased from 66 mg/g DM (untreated material) to 270 and 300 mg/g DM, respectively. The sequent pretreatment of steam explosion and CaO alkalization achieved a sugar yield of 330 mg/g DM, where 2% CaO loading rate was high enough. Besides, SEM, FTIR, and XRD analyses validated structural and physicochemical changes of hippophae. In conclusion, the sequent pretreatment of steam explosion at pressure 1.5 MPa for 20 min and anaerobic CaO alkalization at 2% loading rate could remarkably improve enzymatic hydrolysis of hippophae.


Assuntos
Hippophae/metabolismo , Explosões , Hidrólise , Polissacarídeos/metabolismo , Pressão , Vapor
5.
Bioresour Technol ; 289: 121741, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31323710

RESUMO

In this study, the effect of microalgal strains on the formation of algal-bacterial biofloc was investigated in liquid digestate pretreated by a sequencing batch reactor (SBR), which loaded much aerobic bacteria from activated sludge. Six microalgal strains resulted in three cases: no-bioflocculation (Scenedesmus obliquus and Botryococcus braunii), optimal-bioflocculation with high flocculation activity and good growth (Chlorella sp. BWY-1, Haematococcus pluvialis and Dictyosphaerium ehnenbergianum) and over-bioflocculation with high flocculation activity and bad growth (Chlorella vulgaris). Chlorella sp. BWY-1 provided a better level of flocculation activity and growth. Polysaccharides and proteins were present in EPS of algal-bacterial biofloc, and their distribution was confirmed by staining with alcian blue and fluorescein isothiocyanate (FITC).


Assuntos
Chlorella/metabolismo , Microalgas/metabolismo , Esgotos/microbiologia , Aquicultura , Floculação , Polissacarídeos/metabolismo
6.
Food Chem ; 300: 125194, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31325749

RESUMO

The effects of near freezing temperature (NFT) storage at -1.9 °C on cell wall degradation of 'Shushanggan' apricot was studied comparing to 0 °C and 5 °C storage. Our results indicated that NFT storage strongly inhibited the solubilization of Na2CO3-soluble pectin and cellulose, by the suppression of cell wall modifying enzymes (polygalacturonase, ß-Galactosidase, pectin methyl esterase and cellulase) and related genes expressions. The loss of side chains was the main modification in CDTA (Cyclohexane-diamine-tetraacetic Acid)-soluble pectin during storage and made the main contribution to the softening of apricot, while the loss of side chain was suppressed by NFT storage. Microscopic observation showed that NFT storage delayed the degradation of pectin fraction and protected cell wall structure from loosing. This study proves that NFT storage is an effective technology to suppress the cell wall polysaccharides degradation and ultrastructure modification of apricot.


Assuntos
Parede Celular/ultraestrutura , Armazenamento de Alimentos/métodos , Polissacarídeos/química , Prunus armeniaca/química , Hidrolases de Éster Carboxílico/química , Hidrolases de Éster Carboxílico/metabolismo , Parede Celular/química , Parede Celular/metabolismo , Celulose/química , Temperatura Baixa , Congelamento , Frutas/química , Frutas/citologia , Frutas/ultraestrutura , Pectinas/química , Células Vegetais/química , Células Vegetais/ultraestrutura , Poligalacturonase/química , Poligalacturonase/metabolismo , Polissacarídeos/metabolismo , Prunus armeniaca/citologia , Solubilidade , beta-Galactosidase/química , beta-Galactosidase/metabolismo
7.
J Agric Food Chem ; 67(27): 7755-7764, 2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31251611

RESUMO

Pectic polysaccharides from New Zealand (NZ) spinach (Tetragonia tetragonioides) and karaka berries (Corynocarpus laevigatus) were extracted and analyzed. NZ spinach polysaccharides comprised mostly homogalacturonan (64.4%) and rhamnogalacturonan I (5.8%), with side chains of arabinan (8.1%), galactan (2.2%), and type II arabinogalactan (7.1%); karaka berry polysaccharides comprised homogalacturonan (21.8%) and rhamnogalacturonan I (10.0%), with greater proportions of side chains (arabinan, 15.6%; galactan, 23.8%; and type II arabinogalactan, 19.3%). Screening of gut commensal Bacteroides showed that six were able to grow on the NZ spinach extract, while five were able to grow on the karaka berry extract. Analysis of the polysaccharides remaining after fermentation, by size-exclusion chromatography and constituent sugar analysis, showed that the Bacteroides species that grew on these two substrates showed preferences for the different pectic polysaccharide types. Our data suggest that, to completely degrade and utilize the complex pectin structures found in plants, members of Bacteroides and other bowel bacteria work as metabolic consortia.


Assuntos
Aizoaceae/química , Bacteroides/crescimento & desenvolvimento , Magnoliopsida/química , Pectinas/metabolismo , Polissacarídeos/metabolismo , Bacteroides/metabolismo , Fermentação , Frutas/química , Microbioma Gastrointestinal/fisiologia , Nova Zelândia , Pectinas/análise , Pectinas/química , Folhas de Planta/química , Polissacarídeos/química , Polissacarídeos/isolamento & purificação
8.
Food Chem ; 297: 124945, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31253310

RESUMO

Almond shell, a by-product obtained from the nut industry, was valorised into low degree of polymerisation xylooligosaccharides using alkaline pretreatment and enzymatic hydrolysis. The effect of particle size on hemicellulose recovery upon pretreatment was studied using 1 and 2 M NaOH. It was observed that particle size significantly influences hemicellulose recovery, as particles below 120 µm resulted in near complete recovery at 2 M NaOH. Enzymatic hydrolysis of hemicellulose was optimised using response surface methodology, to obtain efficient xylooligosaccharides production at low enzyme dose and high substrate concentration. For higher XOS yield, an enzyme dose of 10 U and substrate concentration <2% was optimal. The in-vitro human faecal fermentation study revealed no significant difference in gas and short chain fatty acid level among substrates evaluated. It was observed that short chain oligosaccharides produce higher level of acetate than medium chain oligosaccharides.


Assuntos
Fezes/microbiologia , Pentoses/química , Polissacarídeos/metabolismo , Técnicas de Cultura Celular por Lotes , Biomassa , Cromatografia Líquida de Alta Pressão , Endo-1,4-beta-Xilanases/metabolismo , Ácidos Graxos Voláteis/análise , Ácidos Graxos Voláteis/metabolismo , Fezes/química , Gases/química , Glucuronatos/análise , Glucuronatos/metabolismo , Humanos , Hidrólise , Oligossacarídeos/análise , Oligossacarídeos/metabolismo , Tamanho da Partícula , Polissacarídeos/química , Hidróxido de Sódio/química
9.
Plant Mol Biol ; 100(6): 659-674, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31187392

RESUMO

KEY MESSAGE: Oxalotrophic Stenotrophomonas isolated from tomato rhizosphere are able to protect plants against oxalate-producing pathogens by a combination of actions including induction of plant defence signalling callose deposition and the strengthening of plant cell walls and probably the degradation of oxalic acid. Oxalic acid plays a pivotal role in the virulence of the necrotrophic fungi Botrytis cinerea and Sclerotinia sclerotiorum. In this work, we isolated two oxalotrophic strains (OxA and OxB) belonging to the bacterial genus Stenotrophomonas from the rhizosphere of tomato plants. Both strains were capable to colonise endophytically Arabidopsis plants and protect them from the damage caused by high doses of oxalic acid. Furthermore, OxA and OxB protected Arabidopsis from S. sclerotiorum and B. cinerea infections. Bacterial inoculation induced the production of phenolic compounds and the expression of PR-1. Besides, both isolates exerted a protective effect against fungal pathogens in Arabidopsis mutants affected in the synthesis pathway of salicylic acid (sid2-2) and jasmonate perception (coi1). Callose deposition induced by OxA and OxB was required for protection against phytopathogens. Moreover, B. cinerea and S. sclerotiorum mycelial growth was reduced in culture media containing cell wall polysaccharides from leaves inoculated with each bacterial strain. These findings suggest that cell walls from Arabidopsis leaves colonised by these bacteria would be less susceptible to pathogen attack. Our results indicate that these oxalotrophic bacteria can protect plants against oxalate-producing pathogens by a combination of actions and show their potential for use as biological control agents against fungal diseases.


Assuntos
Fungos/patogenicidade , Lycopersicon esculentum/microbiologia , Oxalatos/metabolismo , Stenotrophomonas/fisiologia , Arabidopsis/metabolismo , Botrytis/metabolismo , Botrytis/patogenicidade , Parede Celular/metabolismo , Ciclopentanos/química , Fungos/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Ácido Oxálico/metabolismo , Oxilipinas/química , Filogenia , Doenças das Plantas/microbiologia , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Polissacarídeos/metabolismo , Ácido Salicílico/farmacologia , Transdução de Sinais , Stenotrophomonas/isolamento & purificação
10.
Planta ; 250(2): 395-412, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31236698

RESUMO

MAIN CONCLUSION: Bioethanol from lignocellulosic biomass is a promising step for the future energy requirements. Grass is a potential lignocellulosic biomass which can be utilised for biorefinery-based bioethanol production. Grass biomass is a suitable feedstock for bioethanol production due to its all the year around production, requirement of less fertile land and noninterference with food system. However, the processes involved, i.e. pretreatment, enzymatic hydrolysis and fermentation for bioethanol production from grass biomass, are both time consuming and costly. Developing the grass biomass in planta for enhanced bioethanol production is a promising step for maximum utilisation of this valuable feedstock and, thus, is the focus of the present review. Modern breeding techniques and transgenic processes are attractive methods which can be utilised for development of the feedstock. However, the outcomes are not always predictable and the time period required for obtaining a robust variety is generation dependent. Sophisticated genome editing technologies such as synthetic genetic circuits (SGC) or clustered regularly interspaced short palindromic repeats (CRISPR) systems are advantageous for induction of desired traits/heritable mutations in a foreseeable genome location in the 1st mutant generation. Although, its application in grass biomass for bioethanol is limited, these sophisticated techniques are anticipated to exhibit more flexibility in engineering the expression pattern for qualitative and qualitative traits. Nevertheless, the fundamentals rendered by the genetics of the transgenic crops will remain the basis of such developments for obtaining biorefinery-based bioethanol concepts from grass biomass. Grasses which are abundant and widespread in nature epitomise attractive lignocellulosic feedstocks for bioethanol production. The complexity offered by the grass cell wall in terms of lignin recalcitrance and its binding to polysaccharides forms a barricade for its commercialization as a biofuel feedstock. Inspired by the possibilities for rewiring the genetic makeup of grass biomass for reduced lignin and lignin-polysaccharide linkages along with increase in carbohydrates, innovative approaches for in planta modifications are forging ahead. In this review, we highlight the progress made in the field of transgenic grasses for bioethanol production and focus our understanding on improvements of simple breeding techniques and post-harvest techniques for development in shortening of lignin-carbohydrate and carbohydrate-carbohydrate linkages. Further, we discuss about the designer lignins which are aimed for qualitable lignins and also emphasise on remodelling of polysaccharides and mixed-linkage glucans for enhancing carbohydrate content and in planta saccharification efficiency. As a final point, we discuss the role of synthetic genetic circuits and CRISPR systems in targeted improvement of cell wall components without compromising the plant growth and health. It is anticipated that this review can provide a rational approach towards a better understanding of application of in planta genetic engineering aspects for designing synthetic genetic circuits which can promote grass feedstocks for biorefinery-based bioethanol concepts.


Assuntos
Biocombustíveis , Etanol/metabolismo , Engenharia Genética , Poaceae/genética , Biomassa , Biotecnologia , Fermentação , Hidrólise , Lignina/metabolismo , Melhoramento Vegetal , Plantas Geneticamente Modificadas , Poaceae/crescimento & desenvolvimento , Poaceae/metabolismo , Polissacarídeos/metabolismo , Desenvolvimento Sustentável
11.
Chemistry ; 25(44): 10505-10510, 2019 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-31173420

RESUMO

Precision cell-selective surface glycan remodeling is of vital importance for modulation of cell surface dynamics, tissue-specific imaging, and immunotherapy, but remains an unsolved challenge. Herein, we report a switchable enzymatic accessibility (SEA) strategy for highly specific editing of carbohydrate moieties of interest on the target cell surface. We demonstrate the blocking of enzyme in the inaccessible state with a metal-organic framework (MOF) cage and instantaneous switching to the accessible state through disassembly of MOF. We further show that this level of SEA regulation enables initial guided enzyme delivery to the target cell surface for subsequent cell-specific glycan remodeling, thus providing a temporally and spatially controlled tool for tuning the glycosylation architectures. Terminal galactose/N-acetylgalactosamine (Gal/GalNAc) remodeling and terminal sialic acid (Sia) desialylation have been precisely achieved on target cells even with other cell lines in close spatial proximity. The SEA protocol features a modular and generically adaptable design, a very short protocol duration (ca. 30 min or shorter), and a very high spatial resolving power (ability to differentiate immediately neighboring cell lines).


Assuntos
Membrana Celular/enzimologia , Polissacarídeos/metabolismo , Acetilgalactosamina/química , Acetilgalactosamina/metabolismo , Aptâmeros de Nucleotídeos/química , Biocatálise , Membrana Celular/química , Ativação Enzimática , Galactose/química , Galactose/metabolismo , Galactose Oxidase/antagonistas & inibidores , Galactose Oxidase/metabolismo , Glicosilação , Células Hep G2 , Humanos , Células MCF-7 , Estruturas Metalorgânicas/química , Ácido N-Acetilneuramínico/química , Ácido N-Acetilneuramínico/metabolismo , Imagem Óptica/métodos , Polissacarídeos/química , Propriedades de Superfície
12.
Nat Commun ; 10(1): 2043, 2019 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-31053724

RESUMO

Unlike proteins, glycan chains are not directly encoded by DNA, but by the specificity of the enzymes that assemble them. Theoretical calculations have proposed an astronomical number of possible isomers (> 1012 hexasaccharides) but the actual diversity of glycan structures in nature is not known. Bacteria of the Bacteroidetes phylum are considered primary degraders of polysaccharides and they are found in all ecosystems investigated. In Bacteroidetes genomes, carbohydrate-degrading enzymes (CAZymes) are arranged in gene clusters termed polysaccharide utilization loci (PULs). The depolymerization of a given complex glycan by Bacteroidetes PULs requires bespoke enzymes; conversely, the enzyme composition in PULs can provide information on the structure of the targeted glycans. Here we group the 13,537 PULs encoded by 964 Bacteroidetes genomes according to their CAZyme composition. We find that collectively Bacteroidetes have elaborated a few thousand enzyme combinations for glycan breakdown, suggesting a global estimate of diversity of glycan structures much smaller than the theoretical one.


Assuntos
Proteínas de Bactérias/genética , Bacteroidetes/genética , Enzimas/genética , Genoma Bacteriano/genética , Polissacarídeos/metabolismo , Proteínas de Bactérias/metabolismo , Bacteroidetes/metabolismo , Enzimas/metabolismo , Loci Gênicos , Isomerismo , Polissacarídeos/química
13.
Chem Commun (Camb) ; 55(43): 6114-6117, 2019 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-31070207

RESUMO

Herein, we apply a DNA hybridization chain reaction (HCR) to achieve sensitively amplified imaging of cell surface glycosylation with reduced non-natural monosaccharide units. This method is simple, efficient, sensitive, and possesses great potential to illuminate the pathways via which cell surface glycosylation regulates cell functions.


Assuntos
Hibridização de Ácido Nucleico/métodos , Polissacarídeos/metabolismo , Membrana Celular/metabolismo , Sondas de DNA , Glicosilação , Imagem Óptica
14.
J Agric Food Chem ; 67(21): 5968-5977, 2019 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-31037938

RESUMO

Polysaccharides from functional foods have been proved to have diverse bioactivities, but little is known about what exactly happens to these polysaccharides after oral administration and even less about the underlying mechanism of action. Taking the marker polysaccharide (DOP) of Dendrobium officinale as an example, this study aims to demonstrate the dynamic distribution and degradation of orally dosed DOP in mice and in vitro using near-infrared fluorescence imaging and a kind of chromatographic analysis. The results indicate that (1) neither DOP nor fluorescence-labeled DOP (FDOP) was absorbed, (2) both DOP and FDOP were undigested and were quickly degraded to short-chain fatty acids in the large intestine, (3) DOP modulated gut microbiota, which could be associated with DOP's suppression of 4T1 tumor growth in mice. All of these findings suggest that some (maybe not all) bioactive polysaccharides share a common destiny: indigestible and nonabsorbing, ends in modulating bioactivities-associated gut microbiota.


Assuntos
Dendrobium/metabolismo , Microbioma Gastrointestinal , Extratos Vegetais/metabolismo , Polissacarídeos/metabolismo , Animais , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Bactérias/metabolismo , Dendrobium/química , Feminino , Alimento Funcional/análise , Camundongos , Camundongos Endogâmicos BALB C , Extratos Vegetais/química , Polissacarídeos/química
15.
J Food Sci ; 84(5): 1216-1223, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31066927

RESUMO

Our previous study characterized the structure-associated immunomodulatory effects of an edible Dendrobium aphyllum polysaccharide (DAP), and the in vitro gastrointestinal digestions highlighted DAP could be digested by the GI tract in some extent. Therefore, the present study further explored the digestive properties in vivo to infer the metabolic pathway with health mice model. Results revealed that DAP-treated group showed slightly lower blood glucose levels and significantly higher (P < 0.05) enzyme activities, namely G6Pase and GDH with an increment of about 0.4 to 0.9 and 45 to 91 U/mL, respectively. Meanwhile, DAP up-regulated the expression of glucose transporters, GLUT1 and GLUT2 in the increment rates of 56.34% to 68.28% and 76.63% to 83.03%, in colon. Furthermore, the beneficial effects of DAP on colon were confirmed by the increment of four types short chain fatty acids and the health-promoting microbiota diversity. The above results successfully identify the metabolic pathways after the oral administration of bioactive DAP. PRACTICAL APPLICATION: The metabolic pathways of Dendrobium aphyllum polysaccharide, after artificially stimulated oral administration, were characterized. The most of the unabsorbed portion of DAP were utilized by the colon microbiota, resulting in the significantly increasing production of four health-promoting SCFAs. The unabsorbed portion of DAP upregulated the diversity of various beneficial microbiota genus, and meanwhile downregulated kinds of harmful microbiota genus.


Assuntos
Dendrobium/química , Carboidratos da Dieta , Extratos Vegetais , Polissacarídeos , Animais , Carboidratos da Dieta/isolamento & purificação , Carboidratos da Dieta/metabolismo , Microbioma Gastrointestinal/fisiologia , Redes e Vias Metabólicas , Camundongos , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/metabolismo , Polissacarídeos/isolamento & purificação , Polissacarídeos/metabolismo
16.
Food Chem ; 294: 79-86, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31126508

RESUMO

Millet bran was fermented with Bacillus natto and the changes of structural, physicochemical and functional properties of its dietary fiber were investigated. Results showed that B. natto fermentation enhanced soluble DF content from 2.3% to 13.2%, and soluble DF/insoluble DF ratio from 3.1% to 19.9%. SEM and FTIR assay indicated that fermentation led to the degradation of cellulose and hemicellulose, thereby forming more porous and loose structure and polysaccharides. The binding capacities such as water and oil holding capacity, swelling capacity as well as cholesterol, bile salts, nitrite ion and glucose adsorption capacity were improved, while cation exchange capacity was not significantly changed. The total phenolic content and DPPH free radical scavenging capacity increased significantly. Overall, fermentation of millet bran by B. natto improved the structural and functional properties of its DF, which could be applied as a functional ingredient in food products.


Assuntos
Bacillus subtilis/crescimento & desenvolvimento , Fibras na Dieta/análise , Milhetes/metabolismo , Adsorção , Bacillus subtilis/metabolismo , Reatores Biológicos , Celulose/metabolismo , Colesterol/química , Depuradores de Radicais Livres/química , Fenóis/química , Polissacarídeos/metabolismo , Espectroscopia de Infravermelho com Transformada de Fourier
17.
BMC Plant Biol ; 19(1): 215, 2019 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-31122198

RESUMO

BACKGROUND: Sugarcane is a tropical crop that can accumulate high concentration of sucrose in the stem as a storage carbohydrate. For that reason, sugarcane accounts for approximately 75% of all the sugar produced in the world and has become the main sugar source to produce first-generation bioethanol in Brazil. Daily rhythms cause plants to adapt and coordinate their metabolism to achieve maximum photosynthesis and carbohydrate production throughout the day. Circadian rhythms arise from the interaction of an internal oscillator and external stimuli, whereas diel rhythms occur in response to a light-dark cycle. Diel signalling contributes to synchronizing circadian rhythms to photoperiods, and levels of carbohydrates oscillate in a diel fashion. Under regular photoperiods, they are synthesized during the daytime and consumed throughout the night as an energy reserve. However, short days can induce higher rates of synthesis during daytime and lower rates of consumption in the dark. Cell wall carbohydrates are also diurnally regulated, and it has been shown that celluloses, hemicelluloses and pectin are deposited/degraded at different times of the day. To assess the diel carbohydrate profile in young sugarcane plants, we measured soluble sugars and cell wall components along a time course in plants subjected either to a regular day or short day. RESULTS: Short-day influenced sucrose synthesis and cell wall components. In short-day a 44% increase in sucrose concentration was detected in the dark, but was stable during the day. Cellulose, hemicellulose and pectin also fluctuate within a 24 h interval when subjected to a short day. A 38% increase in leaf sheath cellulose was observed from the middle of the day to the first hour of the night. Leaf sheath pectin and hemicellulose also increased from the day to the night, while it decreased in leaves. CONCLUSIONS: The presented data show diurnal patterns of soluble sugar metabolism together with temporal regulation of cell wall metabolism for a short day, suggesting that diel signalling has a role in how sugarcane manages sugar accumulation and partitioning. Understanding cell wall synthesis/degradation dynamics may help to improve the yield of sugarcane.


Assuntos
Parede Celular/metabolismo , Ritmo Circadiano/fisiologia , Fotoperíodo , Saccharum/fisiologia , Açúcares/metabolismo , Pectinas/metabolismo , Polissacarídeos/metabolismo
18.
BMC Plant Biol ; 19(1): 219, 2019 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-31132986

RESUMO

BACKGROUND: Mature fruit cracking during the normal season in African Pride (AP) atemoya is a major problem in postharvest storage. Our current understanding of the molecular mechanism underlying fruit cracking is limited. The aim of this study was to unravel the role starch degradation and cell wall polysaccharide metabolism in fruit ripening and cracking after harvest through transcriptome analysis. RESULTS: Transcriptome analysis of AP atemoya pericarp from cracking fruits of ethylene treatments and controls was performed. KEGG pathway analysis revealed that the starch and sucrose metabolism pathway was significantly enriched, and approximately 39 DEGs could be functionally annotated, which included starch, cellulose, pectin, and other sugar metabolism-related genes. Starch, protopectin, and soluble pectin contents among the different cracking stages after ethylene treatment and the controls were monitored. The results revealed that ethylene accelerated starch degradation, inhibited protopectin synthesis, and enhanced the soluble pectin content, compared to the control, which coincides with the phenotype of ethylene-induced fruit cracking. Key genes implicated in the starch, pectin, and cellulose degradation were further investigated using RT-qPCR analysis. The results revealed that alpha-amylase 1 (AMY1), alpha-amylase 3 (AMY3), beta-amylase 1 (BAM1), beta-amylase 3 (BAM3), beta-amylase 9 (BAM9), pullulanase (PUL), and glycogen debranching enzyme (glgX), were the major genes involved in starch degradation. AMY1, BAM3, BAM9, PUL, and glgX all were upregulated and had higher expression levels with ethylene treatment compared to the controls, suggesting that ethylene treatment may be responsible for accelerating starch degradation. The expression profile of alpha-1,4-galacturonosyltransferase (GAUT) and granule-bound starch synthase (GBSS) coincided with protopectin content changes and could involve protopectin synthesis. Pectinesterase (PE), polygalacturonase (PG), and pectate lyase (PEL) all involved in pectin degradation; PE was significantly upregulated by ethylene and was the key enzyme implicated pectin degradation. CONCLUSION: Both KEGG pathway enrichment analysis of DEGs and material content analysis confirmed that starch decomposition into soluble sugars and cell wall polysaccharides metabolism are closely related to the ripening and cracking of AP atemoya. A link between gene up- or downregulation during different cracking stages of atemoya fruits and how their expression affects starch and pectin contents were established by RT-qPCR analysis.


Assuntos
Annona/genética , Etilenos/farmacologia , Frutas/crescimento & desenvolvimento , Reguladores de Crescimento de Planta/farmacologia , Polissacarídeos/metabolismo , Annona/metabolismo , Etilenos/administração & dosagem , Frutas/genética , Frutas/metabolismo , Perfilação da Expressão Gênica , Genes de Plantas , Redes e Vias Metabólicas/genética
19.
Carbohydr Res ; 478: 46-53, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-31054382

RESUMO

A novel Lytic Polysaccharide Monooxygenase (LPMO) family AA9 (PMO9A_MALCI) protein from thermophilic fungus Malbranchea cinnamomea was cloned and expressed in Pichia pastoris. The expressed protein was purified to homogeneity using ion exchange and hydrophobic interaction chromatography. SDS-PAGE analysis showed PMO9A_MALCI to be ~27 kDa protein. High performance anion exchange chromatography and mass spectrometry confirmed that purified protein was active against an array of cellulosic (avicel, carboxy methyl cellulose) and hemicellulosic (birch wood xylan, wheat arabinoxylan and rye arabinoxylan) substrates, releasing both oxidized and unoxidized cello-oligosaccharide and xylo-oligosaccharide products respectively. Presence of double oxidized products during mass spectrometric analysis as well as in-silico analysis confirmed that the expressed protein belongs to Type 3 LPMO family. Molecular dynamic simulations further confirmed the sharing of common amino acid residues conserved for catalysis of both cellulosic and hemicellulosic substrates which further indicates that both substrates are equally preferred. Enzymatic cocktails constituted by replacing a part of commercial cellulase CellicCTec2 with PMO9A_MALCI (9:1/8:2) led to synergistic improvement in saccharification of acid and alkali pretreated biomass. This is the first report on heterologous expression of LPMO from M. cinnamomea, exhibiting catalysis of cellulose and pure xylan.


Assuntos
Ascomicetos/enzimologia , Oxigenases de Função Mista/metabolismo , Polissacarídeos/metabolismo , Biocatálise , Configuração de Carboidratos , Oxigenases de Função Mista/química , Simulação de Acoplamento Molecular , Polissacarídeos/química
20.
J Biochem ; 166(3): 245-258, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31102532

RESUMO

Therapeutic proteins are a developing part of the modern biopharmaceutical industry, providing novel therapies to intractable diseases including cancers and autoimmune diseases. The human embryonic kidney 293 (HEK293) cell line has been widely used to produce recombinant proteins in both basic science and industry. The heterogeneity of glycan structures is one of the most challenging issues in the production of therapeutic proteins. Previously, we knocked out genes encoding α1,2-mannosidase-Is, MAN1A1, MAN1A2 and MAN1B1, in HEK293 cells, establishing a triple-knockout (T-KO) cell line, which produced recombinant protein with mainly high-mannose-type N-glycans. Here, we further knocked out MAN1C1 and MGAT1 encoding another Golgi α1,2-mannosidase-I and N-acetylglucosaminyltransferase-I, respectively, based on the T-KO cells. Two recombinant proteins, lysosomal acid lipase (LIPA) and immunoglobulin G1 (IgG1), were expressed in the quadruple-KO (QD-KO) and quintuple-KO (QT-KO) cell lines. Glycan structural analysis revealed that all the hybrid-type and complex-type N-glycans were eliminated, and only the high-mannose-type N-glycans were detected among the recombinant proteins prepared from the QD-KO and QT-KO cells. Overexpression of the oncogenes MYC and MYCN recovered the slow growth in QD-KO and QT-KO without changing the glycan structures. Our results suggest that these cell lines could be suitable platforms to produce homogeneous therapeutic proteins.


Assuntos
Engenharia Genética , Manose/química , Manose/genética , Polissacarídeos/química , Polissacarídeos/genética , Configuração de Carboidratos , Glicosilação , Células HEK293 , Humanos , Manose/metabolismo , Fenótipo , Polissacarídeos/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo
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