Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 3.079
Filtrar
1.
Carbohydr Polym ; 287: 119365, 2022 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-35422308

RESUMO

Polysaccharides are the main macromolecules of colloidal nature in wines. These compounds play a critical role in stabilizing other molecules in solution and thus modifying the wine processing and organoleptic properties. Different analytical techniques have been proposed for their determination. However, most of them are complicated and time-consuming. To overcome these drawbacks, Fourier transform infrared spectroscopy (FTIR) has been evaluated in this study for the estimation of wine polysaccharides in a fast and non-destructive way. Spectral data have been correlated with wine polysaccharide contents by modified partial least squares regression (MPLS) using different spectral pretreatments. MPLS models developed have revealed the potential of FTIR analysis for the routine screening of polysaccharides rich in arabinose and galactose (PRAG), rhamnogalacturonans types II (RG-II), mannoproteins (MP) and total soluble polysaccharides (TSP) in wine samples, obtaining standard errors of prediction from 6.07 to 8.44%. Monitoring the wine polysaccharides can assist in the elaboration of the wines according to their requirements and improving quality to satisfy consumer preferences.


Assuntos
Vinho , Arabinose/análise , Estudos de Viabilidade , Polissacarídeos/química , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Vinho/análise
2.
J Agric Food Chem ; 70(16): 5039-5048, 2022 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-35420820

RESUMO

α-l-Arabinofuranosidase (Abf), a debranching enzyme that can remove arabinose substituents from arabinoxylan, promotes the hydrolysis of hemicellulose in plant biomass. However, the functional specificity of Abfs from different glycoside hydrolase (GH) families on the digestion of arabinoxylan and their synergistic interaction with xylanase have not been systematically studied. In this work, we characterized three Abfs (AxhA, AbfB, and AbfC) from GH62, GH54, and GH51 families in Aspergillus niger An76. Quantitative transcriptional analysis showed that expression of the axhA gene was upregulated as a result of induction by xylose substrates, whereas expression of the abfB gene was mainly induced by arabinose. Recombinant AxhA, AbfB, and AbfC exhibited different hydrolytic performances. AxhA showed the highest catalytic activity toward wheat arabinoxylan (WAX) and tended to hydrolyze monosubstituted arabinofuranose units, whereas AbfB had higher catalytic activity on AN and debranched arabinan (DAN), having the ability to cope with mono- and disubstituted arabinofuranose units. Furthermore, AbfC had greater arabinofuranosidase activity on p-nitrophenyl-α-l-arabinofuranoside (pNP-AraF) than on other substrates. Moreover, three Abfs displayed obvious synergistic action with GH11 xylanase XynB against WAX and barley husk residues. The elucidation of the degradation mechanisms of Abfs will lay a theoretical foundation for the efficient industrialized transformation of arabinoxylans.


Assuntos
Arabinose , Aspergillus niger , Arabinose/metabolismo , Aspergillus niger/genética , Aspergillus niger/metabolismo , Glicosídeo Hidrolases/química , Humanos , Hidrólise , Especificidade por Substrato , Xilanos/química
3.
Int J Biol Macromol ; 207: 730-740, 2022 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-35346678

RESUMO

One galactose- and arabinose-rich polysaccharide isolated from Sambucus adnata was named SPS-1, which had an average molecular weight 138.52 kDa, and was composed of L-rhamnose, D-glucuronic acid, D-galacturonic acid, D-galactose, and L-arabinose in a molar ratio of 0.6:0.4:0.1:4.9:4.0. The primary structure of SPS-1 was further analyzed through methylation and NMR spectroscopy. The results showed that SPS-1 had the structural characteristics of AG-II pectin. The immunoactivity test showed that SPS-1 activated the phosphorylation of MAPKs-related proteins and further elevated the expression levels of related nuclear transcription factors (IκBα and NF-κB p65) in the cells through the TLR2 and MyD88/TRAF6-dependent pathway, thereby significantly enhancing the phagocytosis of macrophages and stimulating the secretion of NO, IL-1ß, IL-6, and TNF-α, which activated the RAW264.7 cells. Therefore, SPS-1, acting as an immunomodulator, is a potential drug for immunological diseases.


Assuntos
Sambucus , Animais , Arabinose , Galactose , Camundongos , Polissacarídeos/química , Células RAW 264.7
4.
Biochem Biophys Res Commun ; 604: 14-21, 2022 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-35279441

RESUMO

l-Arabinose 1-dehydrogenase (AraDH) catalyzes the NAD(P)+-dependent oxidation of l-arabinose to L-arabinono-1,4-lactone in the non-phosphorylative l-arabinose pathway, and is classified into glucose-fructose oxidoreductase and short-chain dehydrogenase/reductase (SDR). We herein report the crystal structure of a SDR-type AraDH (from Herbaspirillum huttiense) for the first time. The interactions between Asp49 and the 2'- and 3'-hydroxyl groups of NAD+ were consistent with strict specificity for NAD+. In a binding model for the substrate, Ser155 and Tyr168, highly conserved in the SDR superfamily, interacted with the C1 and/or C2 hydroxyl(s) of l-arabinose, whereas interactions between Asp107, Arg109, and Gln206 and the C2 and/or C3 hydroxyl(s) were unique to AraDH. Trp200 significantly contributed to the selectivities of the C4 hydroxyl and C6 methyl of substrates.


Assuntos
Arabinose , Redutases-Desidrogenases de Cadeia Curta , Arabinose/química , NAD/metabolismo , Oxirredutases/metabolismo , Redutases-Desidrogenases de Cadeia Curta/metabolismo , Especificidade por Substrato
5.
Food Chem ; 386: 132797, 2022 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-35344725

RESUMO

The objective of this study was to investigate the effect of oximation reagents in simultaneous analysis of mono and di-saccharides using gas chromatography. Sugar oximation with O-ethylhydroxylamine separated all the mono- and di-saccharides while hydroxylamine and O-benzylhydroxylamine could make most of the saccharides separable except for xylose and arabinose. Resolution of xylose: arabinose, galactose: glucose, and fructose: galactose oximated by O-ethylhydroxylamine in DB-1ms column were 1.66, 2.15, and 6.19, respectively, which were above 1.5 and were officially acceptable for quantitative analysis according to the AOAC guideline. The applied method was then verified by the method validation parameters; LOD (0.011-0.02 mg/100 g), LOQ (0.032-0.061 mg/100 g), linearity (R2 = 0.9991-1.0000) and precision (repeatability RSD: 1.4-3.3%, reproducibility RSD: 1.7-7.6%). The greatest amounts of xylose (19.03 ± 0.38 mg/100 g), maltose (6,274.48 ± 173.59 mg/100 g) were found in the oyster sauce, and the contents of glucose (10,565.00 ± 125.31 mg/100 g), galactose (170.40 ± 4.62 mg/100 g) were greatest in soybean paste.


Assuntos
Arabinose , Xilose , Arabinose/análise , Carboidratos , Cromatografia Gasosa , Dissacarídeos/análise , Galactose/análise , Glucose/análise , Indicadores e Reagentes/análise , Reprodutibilidade dos Testes , Xilose/análise
6.
Sci Rep ; 12(1): 4889, 2022 03 22.
Artigo em Inglês | MEDLINE | ID: mdl-35318379

RESUMO

Urinary free-glycans are promising markers of disease. In this study, we attempted to identify novel tumor markers by focusing on neutral free-glycans in urine. Free-glycans extracted from the urine of normal subjects and cancer patients with gastric, colorectal, pancreatic and bile duct were fluorescently labeled with 2-aminopyridine. Profiles of these neutral free-glycans constructed using multidimensional high performance liquid chromatography separation were compared between normal controls and cancer patients. The analysis identified one glycan in the urine of cancer patients with a unique structure, which included a pentose residue. To reveal the glycan structure, the linkage fashion, monosaccharide species and enantiomer of the pentose were analyzed by high performance liquid chromatography and mass spectrometry combined with several chemical treatments. The backbone of the glycan was a monoantennary complex-type free-N-glycan containing ß1,4-branch. The pentose residue was attached to the antennal GlcNAc and released by α1,3/4-L-fucosidase. Intriguingly, the pentose residue was consistent with D-arabinose. Collectively, this glycan structure was determined to be Galß1-4(D-Araß1-3)GlcNAcß1-4Manα1-3Manß1-4GlcNAc-PA. Elevation of D-arabinose-containing free-glycans in the urine of cancer patients was confirmed by selected reaction monitoring. This is the first study to unequivocally show the occurrence of a D-arabinose-containing oligosaccharide in human together with its detailed structure.


Assuntos
Arabinose , Neoplasias , Cromatografia Líquida de Alta Pressão , Glicosídeo Hidrolases , Humanos , Oligossacarídeos/química , Polissacarídeos/química
7.
Int J Biol Macromol ; 205: 76-89, 2022 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-35181328

RESUMO

Polysaccharides coded as CP were extracted from Athyrium Multidentatum (Doll.) Ching and then fractionated into five fractions (FP-1, FP-2, FP-3, FP-4 and FP-5). A purified polysaccharide designated as FP-3-4 was prepared from FP-3 by Sephadex G-100 column chromatography. Chemical analysis disclosed that CP and these fractions were heteropolysaccharides and mainly composed of glucose, galactose, arabinose, mannose, rhamnose, xylose, fucose, ribose and uronic acid with different molar ratios. They presented different images of SEM. FP-3-4 was highly branched polymers with sixteen types of linkages. The in vitro immunomodulatory results stated that CP and these fractions could promote macrophage proliferation, enhance macrophage phagocytosis and increase the production of NO, TNF-α, IFN-γ, IL-1ß, IL-6, IL-10 and IL-2, indicating remarkable immune enhancement activities. RNA sequencing analysis revealed that CP and FP-3 induced macrophage activation mainly through MAPK and alternative NF-κΒ signaling pathways via CD14/TLR4 and Dectin-2 receptors, which were verified by RT-qPCR and western blot.


Assuntos
Fucose , Polissacarídeos , Animais , Arabinose , Galactose/análise , Manose/análise , Camundongos , Polissacarídeos/química , Polissacarídeos/farmacologia , Células RAW 264.7
8.
ACS Synth Biol ; 11(1): 69-76, 2022 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-34989221

RESUMO

To explore the molecular structure of attachment genes, we constructed and characterized a new arabinose-inducible vector for the high-attachment strain Stenotrophomonas AGS-1 isolated from aerobic granular sludge (AGS). mCherry was used as a simple observation biomarker, and the araC-PBAD-inducible promoter was chosen to artificially regulate the expression of target genes. The system achieved little leaky basal expression and high maximal induced expression. The araC-PBAD-based inducible expression was modulated over a wide range of 0.0005 to 0.2% l-arabinose. Notably, a "lag expression" phenomenon was observed in which mCherry was expressed after bacterial growth in LB medium. Using the system and the strategy of fusion expression of target genes (rmlA and AsCas12a) plus mCherry, the recombinant AGS-1 strain achieved the effective induction of rmlA and AsCas12a-mCherry gene expression in the range of 0.0005 to 0.1% l-arabinose. These results demonstrate that the new arabinose-inducible vector could be used as an important molecular tool in the gene function and genome-editing research of strain AGS-1.


Assuntos
Arabinose , Esgotos , Escherichia coli/genética , Regiões Promotoras Genéticas/genética , Stenotrophomonas/genética , Stenotrophomonas/metabolismo
9.
Biochem J ; 479(4): 479-501, 2022 02 17.
Artigo em Inglês | MEDLINE | ID: mdl-35089310

RESUMO

A genetic selection system for activity of HIV protease is described that is based on a synthetic substrate constructed as a modified AraC regulatory protein that when cleaved stimulate l-arabinose metabolism in an Escherichia coli araC strain. Growth stimulation on selective plates was shown to depend on active HIV protease and the scissile bond in the substrate. In addition, the growth of cells correlated well with the established cleavage efficiency of the sites in the viral polyprotein, Gag, when these sites were individually introduced into the synthetic substrate of the selection system. Plasmids encoding protease variants selected based on stimulation of cell growth in the presence of saquinavir or cleavage of a site not cleaved by wild-type protease, were indistinguishable with respect to both phenotypes. Also, both groups of selected plasmids encoded side chain substitutions known from clinical isolates or displayed different side chain substitutions but at identical positions. One highly frequent side chain substitution, E34V, not regarded as a major drug resistance substitution was found in variants obtained under both selective conditions and is suggested to improve protease processing of the synthetic substrate. This substitution is away from the substrate-binding cavity and together with other substitutions in the selected reading frames supports the previous suggestion of a substrate-binding site extended from the active site binding pocket itself.


Assuntos
Fármacos Anti-HIV/farmacocinética , Farmacorresistência Viral/genética , Protease de HIV/genética , Substituição de Aminoácidos , Fator de Transcrição AraC/genética , Arabinose/metabolismo , Quimosina/metabolismo , Escherichia coli , Proteínas de Escherichia coli/genética , Proteínas de Fusão gag-pol/metabolismo , Produtos do Gene gag/metabolismo , Genes araC , Protease de HIV/química , Protease de HIV/isolamento & purificação , Protease de HIV/metabolismo , Modelos Moleculares , Mutação de Sentido Incorreto , Mutação Puntual , Conformação Proteica , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Saquinavir/antagonistas & inibidores , Saquinavir/farmacologia , Seleção Genética , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Relação Estrutura-Atividade , Especificidade por Substrato
10.
J Biosci Bioeng ; 133(4): 316-322, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35031213

RESUMO

Arabinan in plant cell wall constitutes a major source of arabinose and arabino-oligosaccharides in nature. Exo-α-l-1,5-arabinanases release arabinose or arabino-oligosaccharides from arabinan in an exo-acting manner and therefore contribute to arabinan degradation. In this study, an exo-α-l-1,5-arabinanase belonging to GH93 family was identified from the thermophilic filamentous fungus Rasamsonia emersonii. The corresponding encoding gene (Reabn93) was cloned from the R. emersonii genome and heterologously expressed in Pichia pastoris. The purified recombinant ReAbn93 exhibited the maximum activity at 70 °C and retained 70% of its activity after incubation at 70 °C for 3 h ReAbn93 had an acidic pH optimum (pH 4.0) but remained stable over a broad pH range (pH 3-9). The specific activity of ReAbn93 toward linear arabinan under optimal conditions was 466.08 U mg-1. Similar to the few other reported GH93 members, ReAbn93 degrades linear arabinan or arabino-oligosaccharides in an exo-acting manner with arabinobiose as the only hydrolytic product. Of note, ReAbn93 possessed remarkably better thermostability and higher specific activity compared to the only reported thermophilic counterpart in GH93, and therefore holds potential in relevant biotechnological applications.


Assuntos
Eurotiales , Proteínas Fúngicas , Glicosídeo Hidrolases , Arabinose , Eurotiales/enzimologia , Proteínas Fúngicas/metabolismo , Glicosídeo Hidrolases/metabolismo , Especificidade por Substrato
11.
Int J Biol Macromol ; 195: 12-21, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34890634

RESUMO

In order to better utilize the citrus pectin (CP) resource, the crude citrus pectin (CCP), obtained from the citrus fruit canning processing waste water, was purified by cellulose DEAE-52 column, providing neutral polysaccharide CP0 and two acidic polysaccharides (CP1 and CP3). CP1 had the highest yield among the three fractions, being 44.29%. The chemical composition, structure and morphology of these pectin components were analyzed. Monosaccharide composition analysis revealed that arabinose was the most abundant composition in these pectin samples. CCP, CP1 and CP3 were mainly composed of rhamnogalacturonan-I (RG-I) regions. Compared with CP3, CCP and CP1 had longer side chains, which are mainly consisted of arabinose. FT-IR and NMR analysis indicated that α-type glycosidic bonds are the main linkage in the four pectin components. These CP samples were found to possess different conformation, but no triple-helical conformation was observed in all these CP fractions. Scanning electron microscopy revealed that CCP, CP1 and CP3 all had irregular sheet-like structures and partly porous structures. The four pectin components showed the characteristics of non-Newtonian fluids and possessed good viscoelasticity. Due to these properties, the pectin might have potential application in food industry as food thickening agent.


Assuntos
Arabinose/isolamento & purificação , Citrus/química , Glicosídeos/isolamento & purificação , Pectinas/química , Pectinas/isolamento & purificação , Sequência de Carboidratos , Cromatografia DEAE-Celulose , Espectroscopia de Ressonância Magnética , Microscopia de Força Atômica , Microscopia Eletrônica de Varredura , Espectroscopia de Infravermelho com Transformada de Fourier
12.
J Food Biochem ; 45(12): e13991, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34778991

RESUMO

L-arabinose is a good and healthy food additive. This study was conducted to investigate the effect of L-arabinose in a mouse model of type 2 diabetes mellitus (T2DM) induced by exposure to a high-fat diet (HFD) and streptozotocin (STZ). The model mice received L-arabinose at 20 and 60 mg (kg body weight [bw])-1 d-1 , metformin at 300 mg (kg bw)-1 d-1 (positive control) or sterile water (control) via oral gavage. Compared with the model group, mice treated with L-arabinose exhibited attenuated symptoms of diabetes mellitus, including a slower rate of body weight loss, increased homeostasis model assessment of ß-cell function index levels, decreased blood glucose, alleviation of steatosis, and repair of pancreatic islet cells. L-arabinose also exerted an anti-inflammatory effect and partially mitigated dyslipidemia. A 16S-rRNA sequence analysis of the gut microbiota revealed that at the phylum level, treatment with L-arabinose significantly reduced the ratio of Firmicutes to Bacteroidetes due to a decreased relative abundance of Firmicutes; at the genus level, it reversed the increase in the relative abundance of Allobaculum and the decrease abundance of Oscillospira caused by exposure to an HFD and STZ. And the model mice received L-arabinose at 20 mg (kg bw)-1 d-1 had a better effect on improving T2DM than the high-dose group supplemented L-arabinose at 60 mg (kg bw)-1 d-1 . These results strongly suggest L-arabinose as an excellent candidate supplement to prevent or treat T2DM. PRACTICAL APPLICATIONS: L-arabinose, xylitol and sucralose are well-known substitutes for sucrose. L-arabinose has been reported to have beneficial effects on hyperglycemia, glycemic index, and fat accumulation. In this study, we found that low-dose (20 mg (kg bw)-1 d-1 ) supplementation of L-arabinose significantly improved glucose intolerance and gut microbiota incoordination in T2DM caused by HFD and STZ.


Assuntos
Diabetes Mellitus Tipo 2 , Microbioma Gastrointestinal , Animais , Arabinose , Diabetes Mellitus Tipo 2/tratamento farmacológico , Dieta Hiperlipídica/efeitos adversos , Hipoglicemiantes/farmacologia , Hipoglicemiantes/uso terapêutico , Camundongos , Camundongos Endogâmicos C57BL , Estreptozocina
13.
Int J Biol Macromol ; 192: 716-727, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34655584

RESUMO

Streptococcus thermophilus CS6 could produce the high exopolysaccharide (EPS) level in optimized skimmed milk medium. However, physicochemical properties and structure of these polymers have not been fully characterized. In this study, two purified fractions (EPS-M1 and EPS-M2) exhibited good rheology, thermostability and antioxidant activity. Further monosaccharide composition, molecular weight and NMR analysis indicated EPS-M2 was composed of galactose, arabinose and glucose (5:2.5:1) with an average molecular weight of 2.22 × 104 Da and its suggested repeating unit was →6)-[α-L-Araf-(1 â†’ 3)]-ß-D-Galp-(1 â†’ 4)-ß-D-Galp-(1 â†’ 6)-[α-L-Araf-(1 â†’ 5)-{α-L-Araf-(1 â†’ 3)}-α-L-Araf-(1 â†’ 3)]-ß-D-Galp-(1 â†’ 4)-ß-D-Galp-(1 â†’ 6)-[ß-D-Galp-(1 â†’ 5)-α-L-Araf-(1 â†’ 5)-α-L-Araf-(1 â†’ 3)]-ß-D-Galp-(1 â†’ 6)-[ß-D-Galp-(1 â†’ 5)-α-L-Araf-(1 â†’ 5)-{α-L-Araf-(1 â†’ 3)}-α-L-Araf-(1 â†’ 3)]-ß-D-Galp-(1→. High EPS production relied on the expression of eps gene cluster and key enzymes of nucleotide sugar metabolism. Overall, EPS-M2 from a potential functional starter S. thermophilus CS6 provided opportunities for natural thickener, stabilizer, and antioxidant agent exploration in the food industry.


Assuntos
Antioxidantes/química , Antioxidantes/farmacologia , Arabinose/química , Polissacarídeos Bacterianos/química , Polissacarídeos Bacterianos/farmacologia , Streptococcus thermophilus/química , Antioxidantes/isolamento & purificação , Fenômenos Químicos , Sequestradores de Radicais Livres/química , Sequestradores de Radicais Livres/farmacologia , Galactose/química , Espectroscopia de Ressonância Magnética , Metilação , Peso Molecular , Monossacarídeos/química , Polissacarídeos Bacterianos/isolamento & purificação , Reologia , Análise Espectral , Streptococcus thermophilus/genética , Streptococcus thermophilus/metabolismo , Relação Estrutura-Atividade , Termodinâmica
14.
Food Funct ; 12(20): 9855-9865, 2021 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-34664579

RESUMO

Finger citron pomace is a cheap and renewable by-product of the citrus processing industry, representing up to 60% of the fruit biomass. In this study, a pectinase-based and ultrasonic-assisted method was firstly used to extract pectic oligosaccharides (POS) from finger citron pomace. Using the orthogonal experiment design (OED), the maximum conversion rate of up to 64.5% from pomace to POS was obtained under the extraction conditions of 0.25 mg mL-1 pectinase and 50 mg mL-1 pectin at 45 °C and pH 4.5 for 2 h. The extracted POS was then fractionated and purified to homogeneous oligosaccharides (FCPOS-1) with a molecular weight of 2.15 kDa, and the analyses of monosaccharide composition, FTIR, NMR and ESI-MS indicated that FCPOS-1 consisted of GalA and a small amount of mannose, galactose and arabinose. Multiple antioxidant activity assays in vitro revealed that FCPOS-1 possessed remarkable antioxidant properties, especially scavenging activity against DPPH radicals up to 94.07%. FCPOS-1 has the potential to be an effective natural antioxidant for applications in the food and pharmaceutical industries.


Assuntos
Antioxidantes/farmacologia , Citrus/química , Oligossacarídeos/isolamento & purificação , Oligossacarídeos/farmacologia , Pectinas/isolamento & purificação , Poligalacturonase/metabolismo , Arabinose/análise , Fracionamento Químico/métodos , Frutas/química , Galactose/análise , Humanos , Espectroscopia de Ressonância Magnética/métodos , Manose/análise , Peso Molecular , Espectroscopia de Infravermelho com Transformada de Fourier/métodos
15.
Appl Environ Microbiol ; 87(24): e0173021, 2021 11 24.
Artigo em Inglês | MEDLINE | ID: mdl-34613758

RESUMO

PcAxy43B is a modular protein comprising a catalytic domain of glycoside hydrolase family 43 (GH43), a family 6 carbohydrate-binding module (CBM6), and a family 36 carbohydrate-binding module (CBM36) and found to be a novel multifunctional xylanolytic enzyme from Paenibacillus curdlanolyticus B-6. This enzyme exhibited α-l-arabinofuranosidase, endoxylanase, and ß-d-xylosidase activities. The α-l-arabinofuranosidase activity of PcAxy43B revealed a new property of GH43, via the release of both long-chain cereal arabinoxylan and short-chain arabinoxylooligosaccharide (AXOS), as well as release from both the C(O)2 and C(O)3 positions of AXOS, which is different from what has been seen for other arabinofuranosidases. PcAxy43B liberated a series of xylooligosaccharides (XOSs) from birchwood xylan and xylohexaose, indicating that PcAxy43B exhibited endoxylanase activity. PcAxy43B produced xylose from xylobiose and reacted with p-nitrophenyl-ß-d-xylopyranoside as a result of ß-xylosidase activity. PcAxy43B effectively released arabinose together with XOSs and xylose from the highly arabinosyl-substituted rye arabinoxylan. Moreover, PcAxy43B showed significant synergistic action with the trifunctional endoxylanase/ß-xylosidase/α-l-arabinofuranosidase PcAxy43A and the endoxylanase Xyn10C from strain B-6, in which almost all products produced from rye arabinoxylan by these combined enzymes were arabinose and xylose. In addition, the presence of CBM36 was found to be necessary for the endoxylanase property of PcAxy43B. PcAxy43B is capable of hydrolyzing untreated cereal biomass, corn hull, and rice straw into XOSs and xylose. Hence, PcAxy43B, a significant accessory multifunctional xylanolytic enzyme, is a potential candidate for application in the saccharification of cereal biomass. IMPORTANCE Enzymatic saccharification of cereal biomass is a strategy for the production of fermented sugars from low-price raw materials. In the present study, PcAxy43B from P. curdlanolyticus B-6 was found to be a novel multifunctional α-l-arabinofuranosidase/endoxylanase/ß-d-xylosidase enzyme of glycoside hydrolase family 43. It is effective in releasing arabinose, xylose, and XOSs from the highly arabinosyl-substituted rye arabinoxylan, which is usually resistant to hydrolysis by xylanolytic enzymes. Moreover, almost all products produced from rye arabinoxylan by the combination of PcAxy43B with the trifunctional xylanolytic enzyme PcAxy43A and the endoxylanase Xyn10C from strain B-6 were arabinose and xylose, which can be used to produce several value-added products. In addition, PcAxy43B is capable of hydrolyzing untreated cereal biomass into XOSs and xylose. Thus, PcAxy43B is an important multifunctional xylanolytic enzyme with high potential in biotechnology.


Assuntos
Arabinose/metabolismo , Endo-1,4-beta-Xilanases , Paenibacillus/enzimologia , Xilanos , Xilose/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Grão Comestível , Endo-1,4-beta-Xilanases/genética , Endo-1,4-beta-Xilanases/metabolismo , Glicosídeo Hidrolases/genética , Glicosídeo Hidrolases/metabolismo , Enzimas Multifuncionais/genética , Enzimas Multifuncionais/metabolismo , Xilanos/metabolismo , Xilosidases
16.
Microbiol Mol Biol Rev ; 85(4): e0012321, 2021 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-34585982

RESUMO

Accumulation of phosphorylated intermediates during cellular metabolism can have wide-ranging toxic effects on many organisms, including humans and the pathogens that infect them. These toxicities can be induced by feeding an upstream metabolite (a sugar, for instance) while simultaneously blocking the appropriate metabolic pathway with either a mutation or an enzyme inhibitor. Here, we survey the toxicities that can arise in the metabolism of glucose, galactose, fructose, fructose-asparagine, glycerol, trehalose, maltose, mannose, mannitol, arabinose, and rhamnose. Select enzymes in these metabolic pathways may serve as novel therapeutic targets. Some are conserved broadly among prokaryotes and eukaryotes (e.g., glucose and galactose) and are therefore unlikely to be viable drug targets. However, others are found only in bacteria (e.g., fructose-asparagine, rhamnose, and arabinose), and one is found in fungi but not in humans (trehalose). We discuss what is known about the mechanisms of toxicity and how resistance is achieved in order to identify the prospects and challenges associated with targeted exploitation of these pervasive metabolic vulnerabilities.


Assuntos
Lactose , Xilose , Arabinose , Galactose , Humanos , Fosfatos
17.
Neurosci Lett ; 764: 136205, 2021 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-34478818

RESUMO

Lactate transport is an important means of communication between astrocytes and neurons and is implicated in a variety of neurobiological processes. However, the connection between astrocyte-neuron lactate transport and nociceptive modulation has not been well established. Here, we found that Complete Freund's adjuvant (CFA)-induced inflammation pain leads to a significant increase in extracellular lactate levels in the anterior cingulate cortex (ACC). Inhibition of glycogenolysis and lactate release in the ACC disrupted the persistent, but not acute, inflammation pain induced by CFA, and this effect was reversed by exogenous L-lactate administration. Knocking down the expression of lactate transporters (MCT1, MCT4, or MCT2) also disrupted the long lasting inflammation pain induced by CFA. Moreover, glycogenolysis in the ACC is critical for the induction of molecular changes related to neuronal plasticity, including the induction of phospho- (p-) ERK, p-CREB, and Fos. Taken together, our findings indicate that astrocyte-neuron lactate transport in the ACC is critical for the occurrence of persistent inflammation pain, suggesting a novel mechanism underlying chronic pain.


Assuntos
Arabinose/farmacologia , Comunicação Celular/imunologia , Dor Crônica/imunologia , Giro do Cíngulo/patologia , Imino Furanoses/farmacologia , Ácido Láctico/metabolismo , Álcoois Açúcares/farmacologia , Animais , Arabinose/uso terapêutico , Astrócitos/metabolismo , Comunicação Celular/efeitos dos fármacos , Dor Crônica/tratamento farmacológico , Dor Crônica/patologia , Modelos Animais de Doenças , Adjuvante de Freund/administração & dosagem , Adjuvante de Freund/imunologia , Glicogenólise/efeitos dos fármacos , Glicogenólise/imunologia , Giro do Cíngulo/citologia , Giro do Cíngulo/efeitos dos fármacos , Giro do Cíngulo/imunologia , Humanos , Imino Furanoses/uso terapêutico , Masculino , Camundongos , Plasticidade Neuronal/efeitos dos fármacos , Plasticidade Neuronal/imunologia , Neurônios/metabolismo , Álcoois Açúcares/uso terapêutico
18.
Angew Chem Int Ed Engl ; 60(42): 22925-22932, 2021 10 11.
Artigo em Inglês | MEDLINE | ID: mdl-34428345

RESUMO

The template-directed synthesis of RNA played an important role in the transition from prebiotic chemistry to the beginnings of RNA based life, but the mechanism of RNA copying chemistry is incompletely understood. We measured the kinetics of template copying with a set of primers with modified 3'-nucleotides and determined the crystal structures of these modified nucleotides in the context of a primer/template/substrate-analog complex. pH-rate profiles and solvent isotope effects show that deprotonation of the primer 3'-hydroxyl occurs prior to the rate limiting step, the attack of the alkoxide on the activated phosphate of the incoming nucleotide. The analogs with a 3 E ribose conformation show the fastest formation of 3'-5' phosphodiester bonds. Among those derivatives, the reaction rate is strongly correlated with the electronegativity of the 2'-substituent. We interpret our results in terms of differences in steric bulk and charge distribution in the ground vs. transition states.


Assuntos
RNA/metabolismo , Arabinose/química , Cristalografia por Raios X , Primers do DNA/metabolismo , Óxido de Deutério/química , Imidazóis/química , Cinética , Conformação de Ácido Nucleico , Nucleotídeos/química , RNA/química , Relação Estrutura-Atividade , Moldes Genéticos , Água/química
19.
Front Cell Infect Microbiol ; 11: 698146, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34368016

RESUMO

L-arabinose inducible promoters are commonly used in gene expression analysis. However, nutrient source and availability also play a role in biofilm formation; therefore, L-arabinose metabolism could impact biofilm development. In this study we examined the impact of L-arabinose on Salmonella enterica serovar Typhimurium (S. Typhimurium) biofilm formation. Using mutants impaired for the transport and metabolism of L-arabinose, we showed that L-arabinose metabolism negatively impacts S. Typhimurium biofilm formation in vitro. When L-arabinose metabolism is abrogated, biofilm formation returned to baseline levels. However, without the ability to import extracellular L-arabinose, biofilm formation significantly increased. Using RNA-Seq we identified several gene families involved in these different phenotypes including curli expression, amino acid synthesis, and L-arabinose metabolism. Several individual candidate genes were tested for their involvement in the L-arabinose-mediated biofilm phenotypes, but most played no significant role. Interestingly, in the presence of L-arabinose the diguanylate cyclase gene adrA was downregulated in wild type S. Typhimurium. Meanwhile cyaA, encoding an adenylate cyclase, was downregulated in an L-arabinose transport mutant. Using an IPTG-inducible plasmid to deplete c-di-GMP via vieA expression, we were able to abolish the increased biofilm phenotype seen in the transport mutant. However, the mechanism by which the L-arabinose import mutant forms significantly larger biofilms remains to be determined. Regardless, these data suggest that L-arabinose metabolism influences intracellular c-di-GMP levels and therefore biofilm formation. These findings are important when considering the use of an L-arabinose inducible promoter in biofilm conditions.


Assuntos
Arabinose , Proteínas de Bactérias , Biofilmes , Salmonella typhimurium , Arabinose/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , GMP Cíclico , Regulação Bacteriana da Expressão Gênica , Plasmídeos , Salmonella typhimurium/genética , Salmonella typhimurium/metabolismo
20.
Carbohydr Polym ; 272: 118411, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34420705

RESUMO

In this work we have efficiently extracted and characterized pectin from different tissues of astringent (AS) and non-astringent (NAS) persimmon fruits (peel, pulp, whole fruit) for the first time. The highest pectin extraction (≥7.2%) was carried out at 80 °C, 120 min with 1.5% sodium citrate in peel of both AS and NAS persimmon samples. All persimmon pectins showed a molecular weight and galacturonic acid content upper than 328 kDa and 78%, respectively, indicating their suitability as food ingredient. Pectin extracted from AS pulp and peel tissues exhibited an enriched structure in rhamnose and arabinose, whereas the opposite behavior was observed in NAS persimmon whole fruit samples. Remarkably, both pulp tissues (AS and NAS) presented the highest levels of glucose and mannose, non-pectic carbohydrates. In addition, techno-functional assessment (zeta potential, particle size, apparent viscosity, gelation) showed the suitability of the persimmon pectins for a broad range of industrial applications.


Assuntos
Diospyros/química , Frutas/química , Pectinas/análise , Arabinose/análise , Glucose/análise , Ácidos Hexurônicos/análise , Manose/análise , Peso Molecular , Tamanho da Partícula , Ramnose/análise , Reologia/métodos , Citrato de Sódio/química , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Viscosidade
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...