Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 123
Filtrar
Mais filtros

País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Int Microbiol ; 27(1): 311-324, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37386210

RESUMO

Management and improving saline-alkali land is necessary for sustainable agricultural development. We conducted a field experiment to investigate the effects of spraying lactic acid bacteria (LAB) on the cucumber and tomato plant soils. Three treatments were designed, including spraying of water, viable or sterilized LAB preparations to the soils of cucumber and tomato plants every 20 days. Spraying sterilized or viable LAB could reduce the soil pH, with a more obvious effect by using viable LAB, particularly after multiple applications. Metagenomic sequencing revealed that the soil microbiota in LAB-treated groups had higher alpha-diversity and more nitrogen-fixing bacteria compared with the water-treated groups. Both viable and sterilized LAB, but not water application, increased the complexity of the soil microbiota interactive network. The LAB-treated subgroups were enriched in some KEGG pathways compared with water or sterilized LAB subgroups, such as environmental information processing-related pathways in cucumber plant; and metabolism-related pathways in tomato plant, respectively. Redundancy analysis revealed association between some soil physico-chemical parameters (namely soil pH and total nitrogen) and bacterial biomarkers (namely Rhodocyclaceae, Pseudomonadaceae, Gemmatimonadaceae, and Nitrosomonadales). Our study demonstrated that LAB is a suitable strategy for decreasing soil pH and improving the microbial communities in saline-alkali land.


Assuntos
Lactobacillales , Solanum lycopersicum , Álcalis , Bactérias/genética , Solo , Plantas , Água , Microbiologia do Solo
2.
Mar Drugs ; 22(5)2024 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-38786600

RESUMO

The applications of fucoidan in the food industry were limited due to its high molecular weight and low solubility. Moderate degradation was required to depolymerize fucoidan. A few studies have reported that fucoidan has potential antibacterial activity, but its antibacterial mechanism needs further investigation. In this study, the degraded fucoidans were obtained after ultraviolet/hydrogen peroxide treatment (UV/H2O2) at different times. Their physicochemical properties and antibacterial activities against Staphylococcus aureus and Escherichia coli were investigated. The results showed that the average molecular weights of degraded fucoidans were significantly decreased (up to 22.04 times). They were mainly composed of fucose, galactose, and some glucuronic acid. Fucoidan degraded for 90 min (DFuc-90) showed the strongest antibacterial activities against Staphylococcus aureus and Escherichia coli, with inhibition zones of 27.70 + 0.84 mm and 9.25 + 0.61 mm, respectively. The minimum inhibitory concentrations (MIC) were 8 mg/mL and 4 mg/mL, respectively. DFuc-90 could inhibit the bacteria by damaging the cell wall, accumulating intracellular reactive oxygen species, reducing adenosine triphosphate synthesis, and inhibiting bacterial metabolic activity. Therefore, UV/H2O2 treatment could effectively degrade fucoidan and enhance its antibacterial activity.


Assuntos
Antibacterianos , Escherichia coli , Peróxido de Hidrogênio , Testes de Sensibilidade Microbiana , Polissacarídeos , Staphylococcus aureus , Raios Ultravioleta , Polissacarídeos/farmacologia , Polissacarídeos/química , Antibacterianos/farmacologia , Antibacterianos/química , Escherichia coli/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Peso Molecular , Espécies Reativas de Oxigênio/metabolismo
3.
Mar Drugs ; 22(4)2024 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-38667805

RESUMO

Three Laminaria japonica polysaccharides (LJPs) extracted via water extraction (LJP-W), acid extraction (LJP-A), and enzymatic extraction (LJP-E) were used as raw materials to be cross-linked with chitosan and polyvinyl alcohol to prepare hydrogels. Compared with conventional hydrogel systems, all three types of LJP-based polysaccharide hydrogels exhibited better swelling properties (14 times their original weight) and the absorption ability of simulated body fluid (first 2 h: 6-10%). They also demonstrated better rigidity and mechanical strength. Young's modulus of LJP-E was 4 times that of the blank. In terms of hemostatic properties, all three polysaccharide hydrogels did not show significant cytotoxic and hemolytic properties. The enzyme- and acid-extracted hydrogels (LJP-Gel-A and LJP-Gel-E) demonstrated better whole-blood coagulant ability compared with the water-extracted hydrogel (LJP-Gel-W), as evidenced by the whole blood coagulation index being half that of LJP-Gel-W. Additionally, the lactate dehydrogenase viabilities of LJP-Gel-A and LJP-Gel-E were significantly higher, at about four and three times those of water extraction, respectively. The above results suggested that LJP-Gel-A and LJP-Gel-E exhibited better blood coagulation capabilities than LJP-Gel-W, due to their enhanced platelet enrichment and adhesion properties. Consequently, these hydrogels are more conducive to promoting coagulation and have good potential for wound hemostasis.


Assuntos
Coagulação Sanguínea , Algas Comestíveis , Hemostáticos , Hidrogéis , Laminaria , Polissacarídeos , Hidrogéis/química , Hidrogéis/farmacologia , Laminaria/química , Polissacarídeos/química , Polissacarídeos/farmacologia , Polissacarídeos/isolamento & purificação , Coagulação Sanguínea/efeitos dos fármacos , Hemostáticos/farmacologia , Hemostáticos/química , Hemostáticos/isolamento & purificação , Humanos , Animais , Quitosana/química , Quitosana/farmacologia , Álcool de Polivinil/química , Hemostasia/efeitos dos fármacos , Hemólise/efeitos dos fármacos
4.
J Dairy Sci ; 2024 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-38825103

RESUMO

Traditional fermented milks are produced through an inoculation process that involves the deliberate introduction of microorganisms that have been adapted and perpetuated across successive generations. However, the changes in the microbiota of traditional fermented milk during long-term inoculation fermentation in a laboratory environment remain unclear. In this study, we collected 5 samples of traditional fermented milk samples from 5 different counties in Tibet (3 kurut products) and Xinjiang (2 tarag products) of China, which served as starter cultures for a 9-mo continuous inoculation fermentation experiment. We analyzed the inter- and intra-population variations in the microbial communities of the collected samples, representing their macrodiversity and microdiversity, using shotgun metagenomic sequencing. Across all samples, we obtained a total of 186 high-quality metagenomic-assembled genomes, including 7 genera and 13 species with a relative abundance of more than 1%. The majority of these genomes were annotated as Lactobacillus helveticus (60.46%), Enterococcus durans (9.52%), and Limosilactobacillus fermentum (6.23%). We observed significant differences in species composition and abundance among the 5 initial inoculants. During the long-term inoculation fermentation, we found an overall increasing trend in species diversity, composition, and abundances of carbohydrate metabolism module-encoding genes in the fermented milk bacterial metagenome, while the fermented milk virome exhibited a relatively narrow range of variation. Lactobacillus helveticus, a dominant species in traditional fermented milk, displayed high stability during the long-term inoculation fermentation. Our study provides valuable insights for the industrial production of traditional fermented milk.

5.
Mar Drugs ; 21(11)2023 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-37999385

RESUMO

The main purpose of this study was to analyze the structural properties and anti-inflammatory activity of the purified fractions derived from UV/H2O2-degraded polysaccharides from Sargassum fusiforme. Results indicated that twofractions with different monosaccharide compositions and morphological characteristics, PT-0.25 (yield 39.5%) and PT-0.5 (yield 23.9%), were obtained. The average molecular weights of PT-0.25 and PT-0.5 were 14.52 kDa and 22.89 kDa, respectively. In addition, PT-0.5 exhibited better anti-inflammatory activity with a clear dose dependence. The mechanism was associated with the inhibition of LPS-activated Toll-like receptor 4-mediated inflammatory pathways in RAW264.7 cells. The results showed that PT-0.5 was a complex polysaccharide mainly composed of 4-Fucp, t-Manp, 6-Galp, t-Fucp, and 3,4-GlcAp. These results would provide theoretical support for studying the structural properties and biological activities of UV/H2O2-degraded polysaccharides.


Assuntos
Peróxido de Hidrogênio , Sargassum , Peróxido de Hidrogênio/farmacologia , Peróxido de Hidrogênio/metabolismo , Sargassum/química , Polissacarídeos/química , Anti-Inflamatórios
6.
Mar Drugs ; 21(8)2023 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-37623711

RESUMO

The high molecular weight and poor solubility of seaweed polysaccharides have limited their function and application. In this study, ultraviolet/hydrogen peroxide (UV/H2O2) treatment was used to prepare low-molecular-weight seaweed polysaccharides from Sargassum fusiforme. The effects of UV/H2O2 treatment on the physicochemical properties and anti-photoaging activity of S. fusiforme polysaccharides were studied. UV/H2O2 treatment effectively degraded polysaccharides from S. fusiforme (DSFPs), reducing their molecular weight from 271 kDa to 26 kDa after 2 h treatment. The treatment did not affect the functional groups in DSFPs but changed their molar percentage of monosaccharide composition and morphology. The effects of the treatment on the anti-photoaging function of S. fusiforme polysaccharides were investigated using human epidermal HaCaT cells in vitro. DFSPs significantly improved the cell viability and hydroxyproline secretion of UVB-irradiated HaCaT cells. In particular, DSFP-45 obtained from UV/H2O2 treatment for 45 min showed the best anti-photoaging effect. Moreover, DSFP-45 significantly increased the content and expression of collagen I and decreased those of pro-inflammatory cytokines, including interleukin-1ß, interleukin-6, and tumor necrosis factor-α. Thus, UV/H2O2 treatment could effectively improve the anti-photoaging activity of S. fusiforme polysaccharides. These results provide some insights for developing novel and efficient anti-photoaging drugs or functional foods from seaweed polysaccharides.


Assuntos
Peróxido de Hidrogênio , Neoplasias Cutâneas , Humanos , Peróxido de Hidrogênio/farmacologia , Sobrevivência Celular , Colágeno Tipo I , Citocinas
7.
Crit Rev Food Sci Nutr ; 62(32): 9021-9035, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34142906

RESUMO

Photoaging is a complex and multistage process triggered mainly by ultraviolet (UV) radiation due to exposure to sunlight. Photoaging induces DNA damage and oxidative stress that initiate an inflammatory response and an increase of matrix metalloproteinases (MMPs) expression, which results in cumulative changes in skin appearance, structure, and functions, and eventually causes skin carcinogenesis. Dietary polysaccharides from bio-resources have been utilized as functional ingredients in healthy food, cosmetics, and drug due to their good bioactivities. However, a systematic introduction to their effects and underlying mechanisms in anti-photoaging is limited. This review discusses the damage and pathogenesis of UV-induced photoaging and summarizes the up-to-date advances in research on the anti-photoaging activity of non-starch polysaccharides from natural edible resources considering the influence of oxidative stress, DNA damage, MMPs regulation, inflammation, and melanogenesis, primarily focusing on the cellular and molecular mechanisms. This paper will help to understand the anti-photoaging functions of dietary non-starch polysaccharides from natural resources and further application in drug and functional food.


Assuntos
Envelhecimento da Pele , Pele/metabolismo , Pele/patologia , Raios Ultravioleta/efeitos adversos , Metaloproteinases da Matriz/metabolismo , Metaloproteinases da Matriz/farmacologia , Polissacarídeos/farmacologia , Polissacarídeos/metabolismo , Recursos Naturais
8.
Mar Drugs ; 20(12)2022 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-36547917

RESUMO

Long-term exposure to ultraviolet-B (UVB) can cause photoaging. Peptides from Pinctada martensii meat have been shown to have anti-photoaging activities, but their mechanism of action is rarely studied. In this study, Pinctada martensii meat hydrolysates (PME) were prepared by digestive enzymes and then separated by ultrafiltration and Sephadex G-25 gel filtration chromatography to obtain a purified fraction (G2). The fraction G2 was identified by ultra-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS), and peptide sequences were synthesized by solid-phase synthesis. The mechanism of anti-photoaging activities was investigated using a human immortalised epidermal (HaCaT) cell model. Results showed that peptides from Pinctada martensii meat increased UVB-induced cell viability and reduced the contents of interstitial collagenase (MMP-1) and matrix lysing enzyme (MMP-3) in HaCaT cells. Furthermore, the fraction of G2 significantly downregulated the expression of p38, EKR, JNK, MMP-1, and MMP-3 in HaCaT cells. The peptide sequences Phe-His (FH), Ala-Leu (AL), Met-Tyr (MY), Ala-Gly-Phe (AGF), and Ile-Tyr-Pro (IYP) were identified and synthesized. Besides, FH reduced the contents of MMP-1 and MMP-3 in HaCaT cells, combining them effectively in molecular docking analysis. Thus, peptides from Pinctada martensii meat showed anti-photoaging activities and might have the potential to be used as an anti-photoaging agent in functional foods.


Assuntos
Metaloproteinase 1 da Matriz , Peptídeos , Pinctada , Envelhecimento da Pele , Animais , Humanos , Metaloproteinase 1 da Matriz/metabolismo , Metaloproteinase 3 da Matriz/metabolismo , Carne , Simulação de Acoplamento Molecular , Peptídeos/química , Peptídeos/isolamento & purificação , Peptídeos/farmacologia , Pinctada/química , Espectrometria de Massas em Tandem , Raios Ultravioleta , Envelhecimento da Pele/efeitos dos fármacos
9.
Molecules ; 27(15)2022 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-35897872

RESUMO

In this study, a polysaccharide-based hydrogel microsphere (SFP/SA) was prepared using S. fusiforme polysaccharide (SFP) and sodium alginate (SA). Fourier transform infrared spectroscopy (FT-IR) demonstrated that SFP was effectively loaded onto the hydrogel microsphere. Texture profile analysis (TPA) and differential scanning calorimetry (DSC) showed that, with the increase of SFP concentration, the hardness of SFP/SA decreased, while the springiness and cohesiveness of SFP/SA increased, and the thermal stability of SFP/SA improved. The equilibrium adsorption capacity of SFP/SA increased from 8.20 mg/g (without SFP) to 67.95 mg/g (SFP accounted 80%) without swelling, and from 35.05 mg/g (without SFP) to 81.98 mg/g (SFP accounted 80%) after 24 h swelling. The adsorption of crystal violet (CV) dye by SFP/SA followed pseudo-first order and pseudo-second order kinetics (both with R2 > 0.99). The diffusion of intraparticle in CV dye was not the only influencing factor. Moreover, the adsorption of CV dye for SFP/SA (SFP accounted 60%) fit the Langmuir and Temkin isotherm models. SFP/SA exhibited good regenerative adsorption capacity. Its adsorption rate remained at > 97% at the 10th consecutive cycle while SFP accounted for 80%. The results showed that the addition of Sargassum fusiforme polysaccharide could increase the springiness, cohesiveness and thermal stability of the hydrogel microsphere, as well as improve the adsorption capacity of crystal violet dye.


Assuntos
Sargassum , Poluentes Químicos da Água , Adsorção , Alginatos/química , Violeta Genciana/química , Hidrogéis/química , Concentração de Íons de Hidrogênio , Cinética , Microesferas , Espectroscopia de Infravermelho com Transformada de Fourier , Poluentes Químicos da Água/química
10.
Molecules ; 27(20)2022 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-36296508

RESUMO

In this study, polysaccharides from Laminaria japonica (LJP) were produced by the treatment of ultraviolet/hydrogen peroxide (UV/H2O2) degradation into different molecular weights. Then, the degraded LJP were used to prepare LJP/chitosan/PVA hydrogel wound dressings. As the molecular weight of LJP decreased from 315 kDa to 20 kDa, the swelling ratio of the LJP-based hydrogels rose from 14.38 ± 0.60 to 20.47 ± 0.42 folds of the original weight. However, the mechanical properties of LJP-based hydrogels slightly decreased. With the extension of the UV/H2O2 degradation time, the molecular weight of LJP gradually decreased, and the anti-inflammatory activities of LJP-based hydrogels gradually increased. LJP that were degraded for 60 min (60-gel) showed the best inhibition effects on proinflammatory cytokines, while the contents of TNF-α, IL-6, and IL-1ß decreased by 57.33%, 44.80%, and 67.72%, respectively, compared with the Model group. The above results suggested that low Mw LJP-based hydrogels showed great potential for a wound dressing application.


Assuntos
Quitosana , Laminaria , Peso Molecular , Peróxido de Hidrogênio , Fator de Necrose Tumoral alfa , Hidrogéis/farmacologia , Interleucina-6 , Quitosana/farmacologia , Polissacarídeos/farmacologia , Anti-Inflamatórios/farmacologia , Citocinas , Cicatrização
11.
Arch Microbiol ; 203(6): 3305-3315, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33860850

RESUMO

The forest musk deer, Moschus berezovskii, is a nationally protected species of economic importance in China. However, in captive breeding programmes, they usually die as a result of diarrhoea. In this study, six M. berezovskii were randomly selected and divided into two groups: probiotics group (n = 3) and placebo (control) group (n = 3). The two groups were fed a basal diet that included 2 g probiotics (probiotic group) or 2 g whey powder (placebo group) for 30 days. Faecal samples were collected at day 0, 15 and 30 and evaluated for microbial diversity, species richness and metabolic function. Probiotic intervention significantly improved gut health in M. berezovskii by changing the overall community structure of the gut microbiota. Intake of probiotics reduced the relative abundance of pathogenic bacteria such as Escherichia coli and Citrobacter freundii in the intestinal flora and increased the relative abundance of beneficial Bifidobacterium species and other lactic acid bacteria. At the same time, gut microbiota in the probiotics group were involved in regulating degradation of phenylacetic acid and in dTDP-L-rhamnose synthesis; these processes have the potential to enhance immunity in M. berezovskii. This preliminary study revealed the beneficial effects of probiotics on the gut microbiota of M. berezovskii, which the potential to significantly improve the health, wellbeing and economic value of M. berezovskii.


Assuntos
Cervos/microbiologia , Microbioma Gastrointestinal/efeitos dos fármacos , Probióticos/farmacologia , Animais , Bactérias/efeitos dos fármacos , Bactérias/isolamento & purificação , Bactérias/metabolismo , Bifidobacterium/isolamento & purificação , Biodiversidade , China , Fezes/microbiologia , Lactobacillales/isolamento & purificação
12.
Langmuir ; 37(34): 10249-10258, 2021 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-34415769

RESUMO

In the present research, magnetically recyclable polyphosphazene (PCTP)/Ag (MPCTP-Ag) nanoparticles are prepared by a green path, in which PCTP was used to modify Fe3O4 nanoparticles and provide nucleation sites for the reduction of Ag nanoparticles. The prepared MPCTP-Ag nanoparticles were characterized by TEM, SEM, EDS, BET, XRD, vibrating sample magnometry, XPS, and TGA analysis. The catalytic performances of the MPCTP-Ag nanoparticles for the degradation of 4-nitrophenol (4-NP), methylene blue (MB), methyl orange (MO), and their mixtures in the presence of NaBH4 were studied. The main factors affecting the catalytic performance, including temperature, reactant concentration, and catalyst dosage, were investigated. The results showed that the MPCTP-Ag nanoparticles exhibited excellent catalytic activity for the degradation of all three targeted organic contaminants (4-NP, MB, and MO). Moreover, the product retains its catalytic activity after being reused five times by magnetic separation. The results showed that MPCTP-Ag composite nanoparticles were efficient recyclable magnetic nanocatalysts with promising application in environment protection.

13.
Molecules ; 26(8)2021 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-33918007

RESUMO

A pectin/chitosan matrix-loaded curcumin film (PCCF) with a deep eutectic solvent (DES) as the solvent and plasticizer was prepared in this study. Different quantities of curcumin (identified as PCCF-0, PCCF-1, PCCF-2. PCCF-3) were loaded on the pectin/chitosan film in order to evaluate their effects on the film properties. Results showed that curcumin could interact with the pectin/chitosan matrix and form a complex three-dimensional network structure. PCCF could promote the thickness, tensile strength, thermal properties, antioxidant and antiseptic capacities, but deteriorate the light transmission and elongation at the same time. The addition of curcumin would change the color of the film, without significantly affecting the moisture content. The tensile strength of PCCF-3 reached the maximum value of 3.75 MPa, while the elongation decreased to 10%. Meanwhile, the water-resistance properties of PCCF-3 were significantly promoted by 8.6% compared with that of PCCF-0. Furthermore, PCCF showed remarkable sustained antioxidant activities in a dose-dependent manner. PCCF-3 could inhibit DPPH and ABTS free radicals by 58.66% and 29.07%, respectively. It also showed antiseptic capacity on fresh pork during storage. Therefore, curcumin addition could improve the barrier, mechanical, antioxidant and antiseptic properties of the polysaccharide-based film and PCCF has the potential to be used as a new kind of food packaging material in the food industry.


Assuntos
Materiais Biocompatíveis/química , Quitosana/química , Curcumina/farmacologia , Pectinas/química , Anti-Infecciosos Locais/farmacologia , Antioxidantes/farmacologia , Benzotiazóis/química , Compostos de Bifenilo/química , Alimentos , Sequestradores de Radicais Livres/química , Umidade , Picratos/química , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier , Ácidos Sulfônicos/química , Água/química , Difração de Raios X
14.
J Am Chem Soc ; 142(31): 13459-13468, 2020 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-32697094

RESUMO

A rhodium-catalyzed tandem enantioselective C-H silylation/alkene hydrosilylation of dihydrosilanes, which enables the streamlined construction of a wide range of silicon-stereogenic silanes, is successfully developed. This process involves a SiH2-steered highly enantioselective C-H silylation to furnish the corresponding desymmetric monohydrosilanes, which are subsequently trapped with alkenes in a stereospecific fashion to build functionally diverse asymmetrically tetrasubstituted silanes. This general strategy combines readily available dihydrosilanes and alkenes to construct various enantioenriched silicon-stereogenic silanes, including 9-silafluorenes, Si-bridged ladder compounds, and benzosilolometallocenes, in a single step with good to excellent yields and enantioselectivities.

15.
Angew Chem Int Ed Engl ; 59(49): 22217-22222, 2020 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-32841459

RESUMO

A rhodium(I)-catalyzed enantioselective silylation of aliphatic C-H bonds for the synthesis of silicon-stereogenic dihydrobenzosiloles is demonstrated. This reaction involves a highly enantioselective intramolecular C(sp3 )-H silylation of dihydrosilanes, followed by a stereospecific intermolecular alkene hydrosilylation leading to the asymmetrically tetrasubstituted silanes. A wide range of dihydrosilanes and alkenes displaying various functional groups are compatible with this process, giving access to a variety of highly functionalized silicon-stereogenic dihydrobenzosiloles in good to excellent yields and enantioselectivities.

16.
Molecules ; 24(5)2019 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-30813540

RESUMO

Barley contains high level of ß-1,3-1,4-glucans (BBGs) which can be fermented by microbes and are a potential prebiotic. In the present study, native BBG with low viscosity and a MW of 319 kDa was depolymerized by acid hydrolysis to produce a series of four structurally characterized fragments with MWs ranging from 6⁻104 kDa. In vitro fermentation of these BBG samples by infant faecal microbiome was evaluated using a validated deep-well plate protocol as parallel miniature bioreactors. Microbial taxa were identified using 16S amplicon sequencing after 40 h of anaerobic fermentation. Bioinformatics analysis including diversity indexes, predicted metagenomic KEGG functions and predicted phenotypes were performed on the sequenced data. Short chain fatty acids and dissolved ammonia were quantified and the SCFAs/NH3 ratio was used to evaluate the eubiosis/dysbiosis potential. Correlation analysis showed that most of the parameters investigated showed a parabolic function instead of a monotonous function with the BBG samples having different MWs. Among the five BBGs, it was concluded that BBG with an intermediate MW of 28 kDa is the most promising candidate to be developed as a novel prebiotic.


Assuntos
Bactérias/classificação , Fezes/microbiologia , Hordeum/química , beta-Glucanas/metabolismo , Anaerobiose , Bactérias/genética , Bactérias/isolamento & purificação , DNA Ribossômico/genética , Fermentação , Humanos , Hidrólise , Lactente , Peso Molecular , Prebióticos , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Viscosidade
17.
J Nanosci Nanotechnol ; 15(7): 4844-50, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26373045

RESUMO

Single-wall carbon nanotubes (SWNTs) have attractive biochemical properties such as strong cell adhesion and protein absorption, which are very useful for a cell cultivation scaffold. In this study, collagen/SWNT-COOHs nanocomposite films composed of regenerated fish collagen and SWNT-COOHs (0, 0.5, 1.0 and 2.0 weight percent) were prepared by mixing solubilized pepsin-soluble collagen with solutions of SWNT-COOHs. Morphological observation by SEM indicated the homogenous dispersion of SWNT-COOHs in the collagen matrix. The application of FTIR confirmed that the process we applied to prepare the composites did not destroy the native structures of collagen and composites were crosslinked by D-ribose. The biocompatibility was evaluated in vitro using SD rat bone marrow stem cells (BMSCs). Compared with films without transforming growth factor beta 1 (TGF-ß1), films with TGF-ß1 had superior performance on promotion of cell growth. Compared with pure collagen film with TGF-ß1, SWNT-containing films might promote cellular functions by adsorbing more growth factors. In conclusion, the study suggested that the collagen/SWNT-COOHs nanocomposite films with TGF-ß1 were expected to be useful scaffolds in cartilage tissue engineering.


Assuntos
Células da Medula Óssea/metabolismo , Membranas Artificiais , Células-Tronco Mesenquimais/metabolismo , Nanotubos de Carbono/química , Alicerces Teciduais/química , Fator de Crescimento Transformador beta1/farmacologia , Animais , Células da Medula Óssea/citologia , Colágeno/química , Matriz Extracelular/química , Proteínas Imobilizadas/farmacologia , Células-Tronco Mesenquimais/citologia , Camundongos , Nanocompostos/química , Ratos , Ratos Sprague-Dawley
18.
Opt Lett ; 39(22): 6470-3, 2014 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-25490496

RESUMO

The influence of the oxygen sub-stoichiometry on the femtosecond laser-induced damage resistance of Y0.26Hf0.74Ox films was investigated in this work. Photoluminescence (PL) spectroscopy was applied to analyze the various states of oxygen vacancies (V(O)), and laser-induced damage measurement was performed using a single 500 fs pulse laser at a wavelength of 1030 nm. Based on the PL spectra, a probable band gap structure with different defect energy levels was obtained, which is significant in explaining an observed inverse correlation between the laser-induced damage threshold (LIDT) and the concentration of V(O). The crystallization and the refractive index, which were previously found to be crucial factors in laser-induced damage resistance of optical thin films, are also closely dependent on the amount of induced oxygen vacancies.

19.
J Agric Food Chem ; 72(10): 5439-5451, 2024 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-38412221

RESUMO

Increasing hydrogen peroxide (H2O2)-based systems have been developed to degrade various polysaccharides due to the presence of highly reactive free radicals, but published degradation mechanisms are still limited. Therefore, this study aimed to clarify the degradation mechanism of six typical glucosidic bonds from different disaccharides in an ultraviolet (UV)/H2O2 system. The results showed that the H2O2 concentration, disaccharide concentration, and radiation intensity were important factors affecting pseudo-first-order kinetic constants. Hydroxyl radical, superoxide radical, and UV alone contributed 58.37, 18.52, and 19.17% to degradation, respectively. The apparent degradation rates ranked in the order of cellobiose ≈ lactose > trehalose ≈ isomaltose > turanose > sucrose ≈ maltose. The reaction pathways were then deduced after identifying their degradation products. According to quantum chemical calculations, the cleavage of α-glycosidic bonds was more kinetically unfavorable than that of ß-glycosidic bonds. Additionally, the order of apparent degradation rates depended on the energy barriers for the formation of disaccharide-based alkoxyl radicals. Moreover, energy barriers for homolytic scissions of glucosidic C1-O or C7-O sites of these alkoxyl radicals ranked in the sequence: α-(1 → 2) ≈ α-(1 → 3) < α-(1 → 4) < ß-(1 → 4) < α-(1 → 6) < α-(1 → 1) glucosidic bonds. This study helps to explain the mechanisms of carbohydrate degradation by free radicals.


Assuntos
Álcoois , Peróxido de Hidrogênio , Poluentes Químicos da Água , Peróxido de Hidrogênio/química , Glucosídeos , Dissacarídeos/química , Maltose/metabolismo , Sacarose/química , Raios Ultravioleta , Oxirredução , Cinética , Poluentes Químicos da Água/química
20.
Gels ; 10(7)2024 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-39057478

RESUMO

Polysaccharides derived from diverse sources exhibit distinct rheological and gel properties, exerting a profound impact on their applicability in the food industry. In this study, we collected five Gracilaria chouae samples from distinct geographical regions, namely Rizhao (RZ), Lianyungang (LYG), Ningde (ND), Beihai (BH), and a wild source from Beihai (BHW). We conducted analyses on the chemical composition, viscosity, and rheological properties, as well as gel properties, to investigate the influence of chemical composition on variations in gel properties. The results revealed that the total sugar, sulfate content, and monosaccharide composition of G. chouae polysaccharides exhibit similarity; however, their anhydrogalactose content varies within a range of 15.31% to 18.98%. The molecular weight distribution of G. chouae polysaccharides ranged from 1.85 to 2.09 × 103 kDa. The apparent viscosity of the LYG and BHW polysaccharides was relatively high, whereas that of RZ and ND was comparatively low. The gel strength displayed a similar trend. BHW and LYG exhibited solid-like behavior, while ND, RZ, and BH demonstrated liquid-like characteristics at low frequencies. The redundancy analysis (RDA) analysis revealed a positive correlation between the texture profile analysis (TPA) characteristics and anhydrogalactose. The study could provide recommendations for the diverse applications of G. chouae polysaccharides derived from different geographical regions.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA