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1.
Nanoscale ; 13(15): 7285-7293, 2021 Apr 21.
Artículo en Inglés | MEDLINE | ID: mdl-33889923

RESUMEN

Interest in cryo-Electron Microscopy (EM) imaging has skyrocketed in recent years due to its pristine views of macromolecules and materials. As advances in instrumentation and computing algorithms spurred this progress, there is renewed focus to address specimen-related challenges. Here we contribute a microchip-based toolkit to perform complementary structural and biochemical analysis on low-molecular weight proteins. As a model system, we used the SARS-CoV-2 nucleocapsid (N) protein (48 kDa) due to its stability and important role in therapeutic development. Cryo-EM structures of the N protein monomer revealed a flexible N-terminal "top hat" motif and a helical-rich C-terminal domain. To complement our structural findings, we engineered microchip-based immunoprecipitation assays that led to the discovery of the first antibody binding site on the N protein. The data also facilitated molecular modeling of a variety of pandemic and common cold-related coronavirus proteins. Such insights may guide future pandemic-preparedness protocols through immuno-engineering strategies to mitigate viral outbreaks.


Asunto(s)
/química , Microscopía por Crioelectrón , /química , Peso Molecular , Fosfoproteínas/química , Estructura Secundaria de Proteína
2.
Int J Mol Sci ; 22(6)2021 Mar 17.
Artículo en Inglés | MEDLINE | ID: mdl-33802843

RESUMEN

Poisoning with organophosphorus compounds (OPCs) represents an ongoing threat to civilians and rescue personal. We have previously shown that oximes, when administered prophylactically before exposure to the OPC paraoxon, are able to protect from its toxic effects. In the present study, we have assessed to what degree experimental (K-27; K-48; K-53; K-74; K-75) or established oximes (pralidoxime, obidoxime), when given as pretreatment at an equitoxic dosage of 25% of LD01, are able to reduce mortality induced by the OPC azinphos-methyl. Their efficacy was compared with that of pyridostigmine, the only FDA-approved substance for such prophylaxis. Efficacy was quantified in rats by Cox analysis, calculating the relative risk of death (RR), with RR=1 for the reference group given only azinphos-methyl, but no prophylaxis. All tested compounds significantly (p ≤ 0.05) reduced azinphos-methyl-induced mortality. In addition, the efficacy of all tested experimental and established oximes except K-53 was significantly superior to the FDA-approved compound pyridostigmine. Best protection was observed for the oximes K-48 (RR = 0.20), K-27 (RR = 0.23), and obidoxime (RR = 0.21), which were significantly more efficacious than pralidoxime and pyridostigmine. The second-best group of prophylactic compounds consisted of K-74 (RR = 0.26), K-75 (RR = 0.35) and pralidoxime (RR = 0.37), which were significantly more efficacious than pyridostigmine. Pretreatment with K-53 (RR = 0.37) and pyridostigmine (RR = 0.52) was the least efficacious. Our present data, together with previous results on other OPCs, indicate that the experimental oximes K-27 and K-48 are very promising pretreatment compounds. When penetration into the brain is undesirable, obidoxime is the most efficacious prophylactic agent already approved for clinical use.


Asunto(s)
Azinfosmetilo/toxicidad , Oximas/farmacología , Animales , Azinfosmetilo/química , Inhibidores de la Colinesterasa/farmacología , Concentración 50 Inhibidora , Peso Molecular , Compuestos Organofosforados/química , Compuestos Organofosforados/toxicidad , Plaguicidas/química , Plaguicidas/toxicidad , Modelos de Riesgos Proporcionales , Ratas Wistar , Riesgo , Análisis de Supervivencia
3.
Braz J Med Biol Res ; 54(6): e10423, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33886808

RESUMEN

About 3000 tons of beans are not used in human food due to hardening. Several studies on bean-derived bioactive peptides have shown potential to treat some diseases, including those relying on oxidative dysfunctions. We assessed the effects of peptides extracted from hardened bean Phaseolus vulgaris (PV) on reactive oxygen species (ROS) and nitric oxide (NO) production, cytotoxic and cytoprotective effects in endothelial cells, and oxidonitrergic-dependent vasodilating effects. Extract was composed by peptide fraction <3 kDa (PV3) from hardened common bean residue. PV3 sequences were obtained and analyzed with bioinformatics. Human umbilical vein endothelial cells were treated with 10, 20, 30, and 250 µg/mL PV3. Oxidative stress was provoked by 3% H2O2. Cytotoxicity and cytoprotective effects were evaluated by MTT assay, whereas, ROS and NO were quantified using DHE and DAF-FM fluorescent probes by confocal microscopy. NO- and endothelium-dependent vasodilating effects of PV3 were assessed in isolated aortic rings. We found 35 peptides with an average mass of 1.14 kDa. There were no cell deaths with 10 and 20 µg/mL PV3. PV3 at 30 µg/mL increased cell viability, while cytotoxicity was observed only with 250 µg/mL PV3. PV3 at 10 µg/mL was able to protect cells from oxidative stress. PV3 also increased NO release without causing cell death. It also reduced relative ROS production induced by H2O2. PV3 vasodilating effects relied on endothelium-dependent NO release. PV3 obtained from low-commercial-value bean displays little cytotoxicity and exerts antioxidant effects, whereas it increases endothelial NO release.


Asunto(s)
Phaseolus , Antioxidantes/farmacología , Endotelio , Humanos , Peróxido de Hidrógeno , Peso Molecular , Péptidos/farmacología
4.
Nat Commun ; 12(1): 1696, 2021 03 16.
Artículo en Inglés | MEDLINE | ID: mdl-33727542

RESUMEN

Cystobactamids are myxobacteria-derived topoisomerase inhibitors with potent anti-Gram-negative activity. They are formed by a non-ribosomal peptide synthetase (NRPS) and consist of tailored para-aminobenzoic acids, connected by a unique α-methoxy-L-isoasparagine or a ß-methoxy-L-asparagine linker moiety. We describe the heterologous expression of the cystobactamid biosynthetic gene cluster (BGC) in Myxococcus xanthus. Targeted gene deletions produce several unnatural cystobactamids. Using in vitro experiments, we reconstitute the key biosynthetic steps of linker formation and shuttling via CysB to the NRPS. The biosynthetic logic involves a previously uncharacterized bifunctional domain found in the stand-alone NRPS module CysH, albicidin biosynthesis and numerous BGCs of unknown natural products. This domain performs either an aminomutase (AM) or an amide dehydratase (DH) type of reaction, depending on the activity of CysJ which hydroxylates CysH-bound L-asparagine. Furthermore, CysQ O-methylates hydroxyl-L-(iso)asparagine only in the presence of the AMDH domain. Taken together, these findings provide direct evidence for unique steps in cystobactamid biosynthesis.


Asunto(s)
Amidas/metabolismo , Antibacterianos/biosíntesis , Amidas/química , Asparagina/metabolismo , Vías Biosintéticas , Hidroxilación , Modelos Biológicos , Peso Molecular , Myxococcus xanthus/metabolismo , Especificidad por Sustrato
5.
Carbohydr Polym ; 259: 117729, 2021 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-33673993

RESUMEN

The polysaccharide from Ribes nigrum L. (RCP) was modified by nitric acid-sodium selenite method. After purification by Sepharose-6B, high purity native (PRCP) and three selenized polysaccharides (PRSPs) with different selenium contents were obtained. Compared with PRCP, PRSPs possessed the lower molecular weight, better water-solubility, physical stability and rheological properties. FT-IR and NMR spectra confirmed PRSPs had the characteristic absorption peaks of polysaccharides and the glycosidic bond types were not changed after selenylation modification, whereas the selenyl groups existing in PRSPs were mainly introduced at the C-6 position of sugar residue →4)-ß-d-Manp-(1→. Moreover, PRSPs displayed obviously smoother and smaller flaky structure than PRCP, and their inhibitory effects on α-amylase and α-glucosidase also were greater than PRCP. PRSPs exhibited a reversible inhibition on two enzymes in competitive manner and quenched their fluorescence through the static quenching mechanism. The polysaccharide-enzyme complex was spontaneously formed mainly driven by the hydrophobic interaction and hydrogen bonding.


Asunto(s)
Inhibidores Enzimáticos/química , Polisacáridos/química , Ribes/metabolismo , Selenio/química , alfa-Amilasas/antagonistas & inhibidores , alfa-Glucosidasas/química , Inhibidores Enzimáticos/metabolismo , Cinética , Peso Molecular , Polisacáridos/metabolismo , Reología , Temperatura , Termodinámica , alfa-Amilasas/metabolismo , alfa-Glucosidasas/metabolismo
6.
Carbohydr Polym ; 260: 117797, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33712145

RESUMEN

Severe acute respiratory syndrome-related coronavirus-2 (SARS-CoV-2) has resulted in a pandemic and continues to spread at an unprecedented rate around the world. Although a vaccine has recently been approved, there are currently few effective therapeutics to fight its associated disease in humans, COVID-19. SARS-CoV-2 and the related severe acute respiratory syndrome (SARS-CoV-1), and Middle East respiratory syndrome (MERS-CoV) result from zoonotic respiratory viruses that have bats as the primary host and an as yet unknown secondary host. While each of these viruses has different protein-based cell-surface receptors, each rely on the glycosaminoglycan, heparan sulfate as a co-receptor. In this study we compare, for the first time, differences and similarities in the structure of heparan sulfate in human and bat lungs. Furthermore, we show that the spike glycoprotein of COVID-19 binds 3.5 times stronger to human lung heparan sulfate than bat lung heparan sulfate.


Asunto(s)
Heparitina Sulfato/metabolismo , Pulmón/química , Receptores Virales/metabolismo , Glicoproteína de la Espiga del Coronavirus/metabolismo , Animales , Quirópteros , Femenino , Heparitina Sulfato/química , Heparitina Sulfato/aislamiento & purificación , Humanos , Masculino , Estructura Molecular , Peso Molecular , Unión Proteica , Receptores Virales/química , Receptores Virales/aislamiento & purificación
7.
Ter Arkh ; 93(1): 108-113, 2021 Jan 10.
Artículo en Ruso | MEDLINE | ID: mdl-33720635

RESUMEN

During a pandemic, nonspecific immunoprophylaxis of SARS-CoV-2 infection and other acute respiratory infections (ARI), which can worsen the course of COVID-19, is increasingly in demand in addition to specific immunization. BCG vaccine appears to be one of the candidate immunostimulants in this regard. At the same time, other microbe-derived preparations capable of inducing a state of trained immunity deserve attention. BCG and other bacterial immunostimulatory agents containing a large number of biologically active subunits have long been considered as objects of search for promising pharmacological substances. The review analyzes the linkages between BCG, mycobacterial adjuvants, bacterial lysates, trained immunity, muramylpeptides (MPs) and NOD2 receptors in light of the choice of a low molecular weight alternative to multicomponent bacterial immunostimulants for ARI prevention during the COVID-19 pandemic. The search for key molecules by which bacteria stimulate innate and adaptive immune responses proceeds in a spiral. On different loops of this spiral, MPs have repeatedly reproduced the nonspecific effects of multicomponent bacterial adjuvants, vaccines and immunostimulants. MPs and peptidoglycans containing MPs determine the adjuvant properties of the cell walls of mycobacteria and their peptide-glycolipid fraction (wax D). MPs were able to replace Mycobacterium tuberculosis in complete Freunds adjuvant. MPs determine the NOD2-dependent ability of BCG to induce trained immunity. Probably, MPs provide NOD2-mediated long-term prophylactic action of bacterial lysates. All of the above has prompted revisiting the previously obtained evidence of the efficacy of glucosaminylmuramyl dipeptide (GMDP) as a NOD2 agonist in treatment/prevention of respiratory infections. We speculate here that MPs, in particular GMDP, at rational dosing regimens will be able to reproduce many aspects of the nonspecific effects of BCG and multicomponent bacterial immunostimulants in preventing ARI during the COVID-19 pandemic and in the post-pandemic period.


Asunto(s)
Pandemias , Vacuna BCG , Extractos Celulares , Humanos , Inmunidad Innata , Peso Molecular
8.
Carbohydr Polym ; 259: 117553, 2021 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-33674023

RESUMEN

Achyranthes bidentata is a species of flowering plant that is mainly distributed in China. The A. bidentata rhizome is a famous traditional Chinese medicine that has been widely used to treat lumbago, arthritis, and bone hyperplasia. In this work, A. bidentata rhizome was isolated and purified to obtain a pectic polysaccharide (ABPB-4). Chemical and spectral analyses showed that ABPB-4 had a main chain of →4)-α-d-GalpA-(1→ and →2,4)-α-l-Rhap-(1→, and the branch chains included →4)-ß-d-Galp-(1→, →6)-ß-d-Galp-(1→, →3,6)-ß-d-Galp-(1→, →5)-α-l-Araf-(1→ and →3,5)-α-l-Araf-(1→, and it was terminated with α-l-Araf-(1→ and ß-d-Galp-(1→. At concentrations of 0.01, 0.02, and 0.04 µmol/L, ABPB-4 significantly promotes the proliferation, differentiation, and mineralization of MC3T3-E1 cells in vitro, and it appreciably enhances the mRNA expression levels of osteogenic-related genes in these cells. Overall, the results reported herein indicate that ABPB-4 has outstanding osteogenic activity, and that it may be used as an anti-osteoporosis agent in the future.


Asunto(s)
Achyranthes/metabolismo , Polisacáridos/química , Animales , Diferenciación Celular/efectos de los fármacos , Línea Celular , Proliferación Celular/efectos de los fármacos , Subunidad alfa 1 del Factor de Unión al Sitio Principal/genética , Subunidad alfa 1 del Factor de Unión al Sitio Principal/metabolismo , Cromatografía de Gases y Espectrometría de Masas , Regulación de la Expresión Génica/efectos de los fármacos , Ratones , Peso Molecular , Osteogénesis/efectos de los fármacos , Polisacáridos/análisis , Polisacáridos/farmacología , Rizoma/metabolismo , Factor de Transcripción Sp7/genética , Factor de Transcripción Sp7/metabolismo
9.
Int J Mol Sci ; 22(4)2021 Feb 19.
Artículo en Inglés | MEDLINE | ID: mdl-33669634

RESUMEN

Little is known about the effects on hyaluronan (HA) metabolism of UVA radiation. This study demonstrates that the secretion of HA by human dermal fibroblasts (HDFs) is downregulated by UVA, accompanied by the down- and upregulation of mRNA and protein levels of the HA-synthesizing enzyme (HAS2) and the HA-degrading protein, HYaluronan Binding protein Involved in HA Depolymerization(HYBID), respectively. Signaling analysis revealed that the exposure distinctly elicits activation of the p38/MSK1/CREB/c-Fos/AP-1 axis, the JNK/c-Jun axis, and the p38/ATF-2 axis, but downregulates the phosphorylation of NF-kB and JAK/STAT3. A signal inhibition study demonstrated that the inhibition of p38 significantly abrogates the UVA-accentuated mRNA level of HYBID. Furthermore, the inhibition of STAT3 significantly downregulates the level of HAS2 mRNA in non-UVA exposed HDFs. Analysis using siRNAs demonstrated that transfection of ATF-2 siRNA but not c-Fos siRNA abrogates the increased protein level of HYBID in UVA-exposed HDFs. An inhibitor of protein tyrosine phosphatase but not of protein serine/threonine phosphatase restored the diminished phosphorylation level of STAT3 at Tyr 705, accompanied by a significant abolishing effect on the decreased mRNA expression level of HAS2. Silencing with a protein tyrosine phosphatase PTP-Meg2 siRNA revealed that it abrogates the decreased phosphorylation of STAT3 at Tyr 705 in UVA-exposed HDFs. These findings suggest that the UVA-induced decrease in HA secretion by HDFs is attributable to the down- and upregulation of HAS2 and HYBID expression, respectively, changes that are mainly ascribed to the inactivated signaling of the STAT3 axis due to the activated tyrosine protein phosphatase PTP-Meg2 and the activated signaling of the p38/ATF2 axis, respectively.


Asunto(s)
Regulación hacia Abajo/efectos de la radiación , Fibroblastos/efectos de la radiación , Hialuronano Sintasas/metabolismo , Ácido Hialurónico/metabolismo , Hialuronoglucosaminidasa/metabolismo , Transducción de Señal/efectos de la radiación , Rayos Ultravioleta , Regulación hacia Arriba/efectos de la radiación , Factor de Transcripción Activador 2/metabolismo , Muerte Celular/efectos de los fármacos , Muerte Celular/efectos de la radiación , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/efectos de la radiación , Dermis/citología , Regulación hacia Abajo/efectos de los fármacos , Inhibidores Enzimáticos/farmacología , Fibroblastos/efectos de los fármacos , Fibroblastos/metabolismo , Humanos , Janus Quinasa 2/metabolismo , Masculino , Modelos Biológicos , Peso Molecular , Fosforilación/efectos de los fármacos , Fosforilación/efectos de la radiación , ARN Mensajero/genética , ARN Mensajero/metabolismo , Factor de Transcripción STAT3/metabolismo , Regulación hacia Arriba/efectos de los fármacos , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismo
10.
Food Chem ; 352: 129350, 2021 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-33657481

RESUMEN

Fermented cassava products are important starchy food staples in South America. The quality of the products is affected by the baking expansion ability of the dough, which is in turn influenced by the starch fermentation process and drying method employed. We investigated the structural properties of cassava starch after different fermentation and drying treatments, and the effect of starch structure on scalding of dough and baking expansion ability. Fermentation combined with either exposure to sunlight or UV light treatment resulted in high cassava starch baking expansion. Moreover, we observed decreased crystallinity and increased disordered crystalline regions with lower molecular weight in the two types of starch-fermented combined with sunlight or UV light treatment-and both appeared to have a continuous network structure and polarized cross in scalded dough, which are conducive to holding gas and losing water, thus promoting high baking expansibility.


Asunto(s)
Manipulación de Alimentos , Manihot/química , Almidón/química , Desecación , Fermentación , Manihot/efectos de la radiación , Peso Molecular , Luz Solar , Rayos Ultravioleta
11.
Carbohydr Polym ; 260: 117776, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33712132

RESUMEN

Pearl millet (Pennisetum glaucum (L.) R.Br.) is a sustainable and underutilized starch source, constituting up to 70 % starch in its grain. Pearl millet could be used as a cheaper source of starch as compared to other cereals for developing functional foods. This review is mainly focused on isolation methods, and chemical composition of the pearl millet starch (PMS). Techno-functional characteristics such as; gelatinization, pasting properties, solubility, swelling power, and digestibility to infer wider application of the PMS critically highlighted in the review. Native starches have limited functionalitiesfor food applications due to the instability in developed pastes and gels. A number of modifications (physical, mechanical and enzymatic) have been developed to increase the functionality and to obtain desired characteristics of PMS thus improving its utilization in food applications. Further, the utilization of native as well as modified PMS is also discussed comprehensively. In addition, a number of recommendations to further improve its functionality and increase its application are also discussed.


Asunto(s)
Pennisetum/metabolismo , Almidón/química , Portadores de Fármacos/química , Embalaje de Alimentos , Geles/química , Peso Molecular , Nanopartículas/química , Solubilidad , Difracción de Rayos X
12.
Food Chem ; 352: 129399, 2021 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-33662918

RESUMEN

The objective of this study was to investigate the antioxidant properties of cottonseed peptides. Results indicated that cottonseed peptides prepared by enzymatic hydrolysis and microbial fermentation both showed antioxidant properties. The cottonseed protein enzymatic hydrolysate with molecular weight less than 3 kDa exhibited excellent DPPH, ABTS and hydroxyl radical scavenging activity and ferrous ion chelating activity with EC50 values of 0.49 ± 0.02, 2.05 ± 0.02, 2.21 ± 0.12, and 0.99 ± 0.03 mg/mL, respectively. Amino acid composition analysis revealed that cottonseed protein hydrolysates are rich in acidic/basic and aromatic amino acids. In addition, among the 19 identified cottonseed protein-derived peptides, YSNQNGRF had the lowest CDOCKER energy and formed hydrogen bonds with Tyr334, Arg380, Arg415, Ser508, and Ser602, and van der Waals interactions with Asn382, Tyr525, Gln530, and Ser555, which all located in the binding site of Keap1-Nrf2 interaction. These findings suggested that the antioxidant peptides from cottonseed protein had the potential as functional ingredients in foods.


Asunto(s)
Antioxidantes/análisis , Gossypium/química , Péptidos/química , Proteínas de Plantas/química , Semillas/química , Antioxidantes/química , Sitios de Unión , Enlace de Hidrógeno , Hidrólisis , Radical Hidroxilo/química , Peso Molecular
13.
Food Chem ; 352: 129355, 2021 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-33667924

RESUMEN

Low molecular weight (LMW) collagen peptides show skin and bone health benefits for human. However, the production of LMW collagen peptides from land vertebrate sources remains challenging due to the presence of advanced glycation end products (AGEs) cross-links. In this study, the effect of α-amylase pre-treatment on proteolytic production of LMW collagen peptides by papain was investigated; spent hen, bovine, porcine, and tilapia skin collagens (HSC, BSC, PSC, and TSC, respectively) were chosen. Results showed that pre-treatment with α-amylase considerably improved the production of LMW peptides (<2 kDa) from HSC (33.79-67.66%), PSC (86.03-90.85%), BSC (6.60-28.78%), and TSC (89.92-90.27%). The HSC presented the highest carbohydrate content and was increased the most in LMW peptides after amylase pretreatment. These results suggested that α-amylase could cleave glycosidic bonds of AGEs between collagen and thus enhance the production of LMW collagen peptides.


Asunto(s)
Amilasas/metabolismo , Colágeno/metabolismo , Fragmentos de Péptidos/química , Fragmentos de Péptidos/metabolismo , Piel/química , Animales , Bovinos , Pollos , Colágeno/química , Femenino , Humanos , Peso Molecular , Porcinos , Tilapia
14.
Carbohydr Polym ; 260: 117794, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33712142

RESUMEN

Hydrogel beads composed of oxidized gellan gum (OGG) and resistant starch (RS) were successfully fabricated by ionic cross-linking and used as delivery carriers for resveratrol. Firstly, OGG with different degrees of oxidation were prepared through 2, 2, 6, 6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation, and characterized by Fourier transform infrared spectroscopy and carbon-13 nuclear magnetic resonance to prove that carboxyl groups were successfully introduced into the gellan gum molecules. Molecular weight, thermal stability, zeta potential and gelation temperature of OGG were also investigated. Subsequently, resveratrol was encapsulated into OGG/RS hydrogel beads in the form of resveratrol/ß-cyclodextrins inclusion complexes. The addition of RS significantly influenced the morphological structure and swelling capacity of OGG/RS hydrogel beads. The OGG/RS hydrogel beads exhibited a pH-sensitivity and high encapsulation efficiency of resveratrol (84.95 %-90.73 %). Furthermore, the in-vitro release behaviors demonstrated that OGG/RS hydrogel beads showed good stability in simulated gastric fluids and sustained release of resveratrol in simulated intestinal fluids. The obtained results indicate that OGG/RS hydrogel beads show a potential as delivery system for resveratrol in the food industry.


Asunto(s)
Hidrogeles/química , Polisacáridos Bacterianos/química , Resveratrol/química , Óxidos N-Cíclicos/química , Portadores de Fármacos/química , Liberación de Fármacos , Concentración de Iones de Hidrógeno , Peso Molecular , Oxidación-Reducción , Resveratrol/metabolismo , Espectroscopía Infrarroja por Transformada de Fourier , Termogravimetría
15.
Carbohydr Polym ; 260: 117796, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33712144

RESUMEN

The polysaccharide (DRP) was gained from dandelion roots by ultrasonic-assisted enzymatic extraction (UAEE) followed by two-step column purification. Then selenylation of DRP has been accomplished by HNO3-Na2SeO3 method. sDRP-1 and sDRP-2 with the selenium content of 170 ± 1.13 and 710 ± 4.00 µg/g were prepared for further structural characterization and bioactivity determination. DRP, sDRP-1, and sDRP-2 were composed of the same monosaccharides in different molar ratios, and the molecular weights of DRP, sDRP-1 and sDRP-2 were 8700, 7900, and 5600 Da, respectively. Fourier transform infrared (FT-IR) spectra confirmed that DRP, sDRP-1, and sDRP-2 possessed similar functional groups. The results of Congo red test, X-ray diffraction (XRD) and scanning electron microscopy (SEM) showed that DRP, sDRP-1, and sDRP-2 had no three helix structure, did not form single crystal, and all belonged to amorphous morphology. sDRP-1 and sDRP-2 possessed greater antioxidant activities in vitro than the native polysaccharide DRP. At the same time, the selenized polysaccharides showed better immunomodulatory ability and could be used as new-type immunoenhancer. The present conclusions provided theoretical basis for the new application of dandelion polysaccharides and the development of dandelion resources.


Asunto(s)
Antioxidantes/química , Polisacáridos/química , Selenio/química , Taraxacum/metabolismo , Animales , Supervivencia Celular/efectos de los fármacos , Peróxido de Hidrógeno/farmacología , Factores Inmunológicos/química , Factores Inmunológicos/metabolismo , Factores Inmunológicos/farmacología , Macrófagos/citología , Macrófagos/efectos de los fármacos , Macrófagos/metabolismo , Ratones , Peso Molecular , Fagocitosis/efectos de los fármacos , Raíces de Plantas/metabolismo , Polisacáridos/metabolismo , Polisacáridos/farmacología , Células RAW 264.7
16.
Carbohydr Polym ; 260: 117798, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33712146

RESUMEN

The present study was conducted to investigate the structural characteristics of an acid-extracted polysaccharide fraction from mountain tea. The monosaccharide composition revealed that uronic acids (72.4 mol%) considerably predominated in the fraction, followed by smaller amounts of galactose (14.5 mol%) and glucose (6.2 mol%). The fraction contained mostly a highly methyl-esterified homogalacturonan (HG) - 71 mol%. The pectin had a high molecular weight population (∼60-100 kDa). Enzymatic fingerprinting was employed with a combination of HG degrading enzymes and LC-HILIC-MS, HPAEC, HPSEC to examine the structure in greater detail. Unsaturated oligomers released indicated the presence of large blocks of highly methyl-esterified GalA residues. Furthermore, the presence of blocks of non-esterified GalA residues and partly methyl-esterified and acetylated GalA residues in HG domain was demonstrated. The research findings provide a basis for further investigations regarding biological activity and commercial exploitation of mountain tea.


Asunto(s)
Polisacáridos/análisis , Sideritis/metabolismo , Cromatografía Líquida de Alta Presión , Interacciones Hidrofóbicas e Hidrofílicas , Espectrometría de Masas , Peso Molecular , Pectinas/química , Poligalacturonasa/metabolismo , Polisacaridoliasas/metabolismo , Polisacáridos/aislamiento & purificación , Polisacáridos/metabolismo
17.
Carbohydr Polym ; 260: 117825, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33712166

RESUMEN

Polysaccharide ASK was isolated from the Abies sibirica foliage by extraction with an aqueous KOH solution. ASK was shown to contain structurally different polymers such as arabinoglucuronoxylans, xyloglucans, glucomannans, arabinogalactan-proteins (AGPs). The pectic polysaccharides were also found in the alkaline extract of ASK and were represented by regions of homogalactorunan and rhamnogalactouronan-I whose side sugar chains were made up chiefly of highly branched 1,5-α-l-arabinan. The potential couplings between those polysaccharides were examined. Our studies showed simultaneous elution of pectin, xyloglucans, arabinoglucuronoxylans and AGPs, indicating that pectins can be covalently bound to the other cell-wall polysaccharides. NMR spectroscopy results revealed that the polysaccharides obtained by ion-exchange chromatography almost had no free reducing ends. These findings corroborate the conclusion that pectin, AGPs, glucan and xylan are bound together. The existence of the covalently bound complex of pectin-xylan-xyloglucan-AGP is suggested herein. Pectin and xylan are hypothesized to be covalently linked through RG-I regions.


Asunto(s)
Abies/metabolismo , Glucanos/química , Mucoproteínas/química , Pectinas/química , Polisacáridos/análisis , Xilanos/química , Hidrólisis , Espectroscopía de Resonancia Magnética , Peso Molecular , Proteínas de Plantas/química , Polisacáridos/metabolismo , Siberia
18.
Carbohydr Polym ; 260: 117828, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33712168

RESUMEN

Green technique for hydrolysis of chitosan was developed using novel Brønsted Acidic Ionic Liquids (BAILs) as homogenous reusable catalysts. Efficiency of BAILs in controlling stochastic and irregular breakdown of chitosan was compared with that of mineral acids. Structural elucidation of the novel BAILs was performed using H1-NMR evaluation and supplemented using mass spectroscopy. Additionally, thermal characterization was conducted using TGA-DTA analysis, while acidity was estimated by deriving the Hammet acidity function. BAILs investigated in this work enabled consistent production of LMWCS variants, with minimum formation of residual impurities. Around 80 % reduction in molecular weight was noted as compared to original under extreme conditions employed. Further, Box-Behnken Design (BBD) was implemented to optimize effect of processing parameters for conversion of chitosan to low molecular weight congeners.


Asunto(s)
Quitosano/química , Líquidos Iónicos/química , Catálisis , Tecnología Química Verde , Hidrólisis , Peso Molecular , Temperatura
19.
Carbohydr Polym ; 260: 117830, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33712169

RESUMEN

The manifold array of saccharide linkages leads to a great variety of polysaccharide architectures, comprising three conformations in aqueous solution: compact sphere, random coil, and rigid rod. This conformational variation limits the suitability of the commonly applied molecular weight cut-off (MWCO) as selection criteria for polysaccharide ultrafiltration membranes, as it is based on globular marker proteins with narrow Mw and hydrodynamic volume relation. Here we show the effect of conformation on ultrafiltration performance using randomly coiled pullulan and rigid rod-like scleroglucan as model polysaccharides for membrane rejection and molecular weight distribution. Ultrafiltration with a 10 kDa polyethersulfone membrane yielded significant different recoveries for pullulan and scleroglucan showing 1% and 71%, respectively. We found deviations greater than 77-fold between nominal MWCO and apparent Mw of pullulan and scleroglucan, while recovering over 90% polysaccharide with unchanged Mw. We anticipate our work as starting point towards an optimized membrane selection for polysaccharide applications.


Asunto(s)
Polisacáridos/química , Ultrafiltración/métodos , Glucanos/química , Glucanos/aislamiento & purificación , Membranas Artificiales , Conformación Molecular , Peso Molecular , Polímeros/química , Polisacáridos/aislamiento & purificación , Sulfonas/química
20.
Poult Sci ; 100(3): 100967, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33652524

RESUMEN

The reduced use of antibiotics in poultry feed has led to the investigation of alternatives to antibiotics, and one such substitution is fermentable carbohydrates. Exogenous ß-glucanase (BGase) is commonly used in poultry fed barley-based diets to reduce digesta viscosity. The effects of hulless barley (HB) and BGase levels on ileal digesta soluble ß-glucan molecular weight, digestive tract characteristics, and performance of broiler chickens were determined. A total of 360 day-old broilers were housed in battery cages (4 birds per cage) and fed graded levels of high ß-glucan HB (CDC Fibar; 0, 30, and 60% replacing wheat) and BGase (Econase GT 200 P; 0, 0.01, and 0.1%) in a 3 × 3 factorial arrangement. Beta-glucan peak molecular weight in the ileal digesta was lower with 30 and 60 than 0% HB, whereas the peak decreased with increasing BGase. The weight average molecular weight was lower at 0.1 than 0% BGase in wheat diets, whereas in HB diets, it was lower at 0.01 and 0.1 than 0% BGase. The maximum molecular weight was lower with 0.01 and 0.1 than 0% BGase regardless of the HB level. The maximum molecular weight was lower with HB than wheat at 0 or 0.01% BGase. Overall, empty weights and lengths of digestive tract sections increased with increasing HB, but there was no BGase effect. Hulless barley decreased the duodenum and jejunum contents, whereas increasing the gizzard (diets with BGase), ileum, and colon contents. The jejunum and small intestine contents decreased with increasing BGase. Ileal and colon pH increased with increasing HB, but there was no BGase effect. Treatment effects were minor on short-chain fatty acids levels and performance. In conclusion, exogenous BGase depolymerized the ileal digesta soluble ß-glucan in broiler chickens in a dose-dependent manner. Overall, feed efficiency was impaired by increasing HB levels. However, HB and BGase did not affect carbohydrate fermentation in the ileum and ceca, although BGase decreased ileal viscosity and improved feed efficiency at the 0.1% dietary level.


Asunto(s)
Pollos , Dextranasa , Dieta , Tracto Gastrointestinal , Hordeum , beta-Glucanos , Alimentación Animal/análisis , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Pollos/crecimiento & desarrollo , Pollos/metabolismo , Dextranasa/metabolismo , Dextranasa/farmacología , Dieta/veterinaria , Digestión , Tracto Gastrointestinal/metabolismo , Hordeum/clasificación , Hordeum/metabolismo , Íleon/metabolismo , Peso Molecular , beta-Glucanos/química
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