RESUMEN
In this study, crude polysaccharide (LAG-C) and homogeneous arabinogalactan (LAG-W) were isolated from Qinling Larix kaempferi of Shaanxi Province. Bioactivity assays showed that LAG-W and LAG-C enhanced the phagocytic ability, NO secretion, acid phosphatase activity, and cytokine production (IL-6, IL-1ß, and TNF-α) of RAW264.7 macrophages. Notably, LAG-W exhibited a significantly stronger immunomodulatory effect than LAG-C. The primary structure of LAG-W was characterised by chemical methods (monosaccharide composition, methylation analysis, and alkali treatment) and spectroscopic techniques (gas chromatography-mass spectrometry, high-performance liquid chromatography-mass spectrometry, and 1D/2D nuclear magnetic resonance). LAG-W was identified as a 22.08 kilodaltons (kDa) neutral polysaccharide composed of arabinose and galactose at a 1:7.5 molar ratio. Its backbone consisted of repeated â3)-ß-Galp-(1â residues. Side chains, connected at the O-6 position, were mainly composed of T-ß-Galp-(1â and T-ß-Galp-(1â6)-ß-Galp-(1â residues. And it also contained small amounts of T-ß-Arap-(1â, T-α-Araf-(1â6)-ß-Galp-(1â6)-ß-Galp-(1â, and T-α-Araf-(1â3)-α-Araf-(1â6)-ß-Galp-(1â residues. By structurally and functionally characterising L. kaempferi polysaccharides, this study opens the way for the valorisation of this species.
Asunto(s)
Larix , Galactanos/farmacología , Galactanos/química , Polisacáridos/farmacología , Polisacáridos/química , Espectroscopía de Resonancia MagnéticaRESUMEN
Structurally defined arabinogalactan (LBP-3) from Lycium barbarum have effect on improving intestinal barrier function. However, whether its intestinal barrier function depended on the changes of intestinal mucin O-glycans have not been investigated. A dextran sodium sulfate-induced acute colitis mouse model was employed to test prevention and treatment with LBP-3. The intestinal microbiota as well as colonic mucin O-glycan profiles were analyzed. Supplementation with LBP-3 inhibited harmful bacteria, including Desulfovibrionaceae, Enterobacteriaceae, and Helicobacteraceae while significantly increased the abundance of beneficial bacteria (e.g., Lachnospiraceae, Ruminococcaceae, and Lactobacillaceae). Notably, LBP-3 augmented the content of neutral O-glycans by stimulating the fucosylation glycoforms (F1H1N2 and F1H2N2), short-chain sulfated O-glycans (S1F1H1N2, S1H1N2, and S1H2N3), and sialylated medium- and long-chain O-glycans (F1H2N2A1, H2N3A1, and F1H3N2A1). In summary, we report that supplement LBP-3 significantly reduced pathological symptoms, restored the bacterial community, and promoted the expression of O-glycans to successfully prevent and alleviate colitis in a mouse model, especially in the LBP-3 prevention testing group. The underlying mechanism of action was investigated using glycomics to better clarify which the structurally defined LBP-3 were responsible for its beneficial effect against ulcerative colitis and assess its use as a functional food or pharmaceutical supplement.
Asunto(s)
Colitis , Galactanos , Lycium , Ratones , Animales , Mucinas/metabolismo , Lycium/metabolismo , Colitis/inducido químicamente , Colitis/tratamiento farmacológico , Colitis/metabolismo , Polisacáridos/efectos adversos , Bacterias/metabolismo , Ratones Endogámicos C57BL , Modelos Animales de EnfermedadRESUMEN
As one of the most important two-dimensional (2D) materials, BN nanosheets attracted intensive interest in the past decade. Although there are many methods suitable for the preparation of BN sheets, finding a cheap and nontoxic way for their mass and high-quality production is still a challenge. Here we provide a highly effective and cheap way to synthesize gram-scale-level well-structured BN nanosheets from many common graphite products as source materials. Single-crystalline multi-layered BN sheets have a mean lateral size of several hundred nanometers and a thickness ranging from 5â nm to 40â nm. Cathodoluminescence (CL) analysis shows that the structures exhibit a near band-edge emission and a broad emission band from 300â nm to 500â nm. Utilization of nanosheets for the reinforcement of polymers revealed that the Young's modulus of BN/PMMA composite had increased to 1.56â GPa when the BN's fraction was only 2 wt.%, thus demonstrating a 20% gain compared to a blank PMMA film. It suggests that the BN nanosheet is an ideal mechanical reinforcing material for polymers. In addition, this easy and nontoxic substitution method may provide a universal route towards high yields of other 2D materials.
RESUMEN
Ultra-long AlN nanowire arrays are prepared by chemical vapor deposition, and the photoconductive performances of individual nanowires are investigated in our self-built measurement system. Individual ultra-long AlN nanowire (UAN) exhibits a clear photoconductive effect under different excited lights. We attribute the positive photocurrent response of individual UAN to the dominant molecular sensitization effect. It is found that they have a much faster response speed (a rise and decay time of about 1 ms), higher photocurrent response (2.7×106), and more reproductive working performance (the photocurrent fluctuation is lower than 2%) in the air environment. Their better photoconductive performances are comparable to many nanostructures, which are suggested to be a candidate for building promising photosensitive nanodevices in the future.