Publications by authors named "Yu-Guang Du"

Astragali Radix polysaccharides (APSs) have a wide range of biological activities. Our preliminary experiment showed that APS-Ⅱ (10 kDa) was the main immunologically active component of APSs. However, the characteristic structure related to activity of APS-Ⅱ needs further verification and clarification.

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polysaccharides (APS) have a wide range of biological activities. Most researchers discuss total APS as the main research object. However, because the relative molecular weight of APS has a wide distribution, in-depth studies on the mechanisms of the biological activity of notable molecules are limited.

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Objective: Based on trifluoroacetic acid (TFA) hydrolysis, polyacrylamide gel electrophoresis (PAGE) and high performance thin layer chromatography (HPTLC) analysis, the carbohydrate responsible for immunomodulatory activity are used as quality indicators for (AR).

Methods: In this study, 24 batches of AR from different germplasm resources were selected as the research object, and AR polysaccharides were extracted. PAGE and HPTLC methods were used to analyze the partial acid hydrolyzate of AR polysaccharides and obtain a series of saccharide fingerprints.

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Background: Human papillomaviruses (HPVs), a group of non-enveloped small viruses with double-stranded circular DNA which lead to multiple skin diseases such as benign warts, are commonly seen in clinics. The current HPV detection systems aim mainly at mucosal HPVs, however, an efficient clinical approach for cutaneous HPVs detection is lacking.

Objectives: To establish a rapid detection system for cutaneous HPVs using a colorimetric loop-mediated isothermal amplification (LAMP) with hydroxynaphthol blue (HNB) dye in combination with microfluidic technology.

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Astragali Radix( AR) polysaccharide for injection( Guoyao Zhunzi Z20040086) is a traditional Chinese medicine for intravenous powder injection developed by Shanxi Academy of Traditional Chinese Medicine in early 1990 s by taking advantage of AR resources in Shanxi province. The effective parts of AR polysaccharides were obtained by advanced technology. The hemogram of patients with radiotherapy and chemotherapy showed alleviations in clinic.

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Inulinase is an enzyme that belongs to glycoside hydrolase family 32. It converts inulin into high-fructose syrups and fructoligosaccharides, both of which are widely used in pharmaceutical and food industries. In this study, the kcINU1 gene (GenBank accession number AF178979) encoding an exoinulinase was cloned from Kluyveromyces cicerisporus CBS4857 and expressed in Pichia pastoris X-33, yielding a maximum of 45.

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An alginate lyase gene, algA, encoding a new poly β-D-mannuronate (polyM)-specific alginate lyase AlgA, was cloned from Pseudomonas sp. E03. The recombinant AlgA with (His)6-tag, consisting of 364 amino acids (40.

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It is known that chitosan oligosaccharides (COS) suppress LPS-induced vascular endothelial inflammatory response by mechanism involving NF-κB blockade. It remains unknown how COS inhibit NF-κB. We provided evidence both in cultured endothelial cells and mouse model supporting a new mechanism.

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A Gram-negative, aerobic, rod-shaped, motile, non-spore-forming bacterial strain, designated 13-Q(T), was isolated from seaside soil under the stacks of the red algae in Hainan province in China. Identification was carried out on the basis of polyphasic taxonomy. Phylogenetic analysis of 16S rRNA gene sequences showed that strain 13-Q(T) belonged to the genus Pedobacter, and the highest similarity was 94.

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Alginate oligosaccharides (AOS) prepared from degradation of alginate is a potent plant elicitor. Hydroponic experiments were carried out to investigate the mechanism of AOS on improving Triticum aestivum L. resistant ability to drought stress.

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Chitosan oligosaccharides (COS) have been reported to exert many biological activities, such as antioxidant, antitumor and anti-inflammatory effects. In the present study, we examined the effect of COS on nitric oxide (NO) production in LPS induced N9 microglial cells. Pretreatment with COS (50~200 μg/ml) could markedly inhibit NO production by suppressing inducible nitric oxide synthase (iNOS) expression in activated microglial cells.

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Aim: To investigate whether and how COS inhibited IL-8 production in LPS-induced human umbilical vein endothelial cells (HUVECs).

Methods: RT-PCR, enzyme-linked immunosorbent assays (ELISA) and Western blotting were used to study IL-8 expression and related signaling pathway. Wound healing migration assays and monocytic cell adhesion analysis were used to explore the chemotactic and adhesive activities of HUVECs.

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Sepsis and its derivative syndromes are major causes of morbidity and mortality in the intensive care unit. Recently, lots of studies have shown that the progression of sepsis is attributed to redox imbalance and overproduction of proinflammatory cytokines. In previous studies, we have reported the anti-oxidative and anti-inflammatory effects of chitosan oligosaccharides in vitro.

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Aim Of The Study: To determine the inhibitory effect of tetramethylpyrazine (TMP) on lipopolysaccharide (LPS)-induced over-production of nitric oxide (NO) and inducible nitric oxide synthase (iNOS) in N9 microglial cells.

Materials And Methods: N9 cells were pretreated with vehicle or TMP and then exposed to LPS for the time indicated. Cell viability was determined by methylthiazoyltetrazolium (MTT) assay.

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Objective: The aim of this study was to investigate the inhibitory effect of geniposide on lipopolysaccharide (LPS)-induced interleukin-6 (IL-6) and interleukin-8 (IL-8) production in human umbilical vein endothelial cells (HUVECs).

Materials And Methods: Primary HUVECs were used. The mRNA/protein levels of IL-6 and IL-8 was determined by reverse transcription-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA).

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Chitosan oligosaccharides (COS) have been reported to exert anti-fungal activities, antitumour activities and immuno-enhancing effects. However, the potential roles of COS in the treatment of vascular inflammations remain unknown. In the present study, we examined the effects of COS on interleukin-6 (IL-6) production in human umbilical vein endothelial cells (HUVECs) induced by lipopolysaccharide (LPS).

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In order to study Brassica napus fatty acid (FA) metabolism and relevant regulatory networks, a systematic identification of fatty acid (FA) biosynthesis-related genes was conducted. Following gene identification, gene expression profiles during B. napus seed development and FA metabolism were performed by cDNA chip hybridization (>8000 EST clones from seed).

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Chitosan oligosaccharides (COS) have been reported to have anticancer activity, immuno-enhancing effect and antimicrobial activity. However, other biological activities are unknown. Herein, we investigated the protective effects of COS against hydrogen peroxide (H(2)O(2))-induced oxidative damage on human umbilical vein endothelial cells (HUVEC, ECV304 cells).

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To confirm the inactivating effect of chito-oligosaccharides on Tobacco mosaic virus (TMV) par ticles in vitro, the difference of TMV pathogenicity was evaluated according to the decrease of local lesion numbers after inoculating with TMV mixed with chito-oligosaccharides (DP3-10) in Nicotiana glutinosa, and the virion structural change was studied by transmission electron microscopy after mixed with chito-oligosaccharides. In the range of tested concentrations of chito-oligosaccharides (100-1000 microg /mL), the numbers of local lesions were strongly reduced with over 30% decrement, and the 88.4% reduction gained at the concentration of 600g /mL.

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In order to reveal the antithrombotic mechanism of propylene glycol mannite sulfate (PGMS) on gene level and explore the correlation between PGMS and fibrinolytic system, the urokinase-type plasminogen activator (uPA) mRNA expression and uPA activity were detected in vitro and in vivo with semi-quantitative reverse transcription (RT)-PCR and chromogenic method. The results showed that PGMS was able to increase uPA activity in dosage-dependent manner in rat plasma, which resulted in the increase of rat fibrinolytic activity. The change of rat uPA mRNA expression with PGMS was similar to that of uPA activity.

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Oligochitosan is an effective inductor for plant resistance. To understand the induced resistance mechanism, mRNA differential display was used to isolate genes from Nicotiana tabacum var. Samsun NN and four enhanced-expression gene fragments were obtained and were reamplified.

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Objective: To study the chemical constituents from the herb of Gentianopsis paludosa.

Method: Column chromatogrophy and spectral analysis were used to isolate and identify the constituents.

Result: Six compounds were isolated and identified as 1,7-dihydroxy-3,8-dimethoxyxanthone (I), 1-hydroxy-3, 7, 8-trimethoxyxanthone (II), 1, 8-dihydroxy-3, 7-dimethoxyxanthone (III), 1-hydroxy-3, 7-dimethoxyxanthone (IV), beta-sitosterol (V), daucosterol (VI).

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A new xanthone glycoside (1) has been isolated from Swertia franchetiana together with five known xanthone glycosides. Their structures were elucidated as 7-O-[beta-D-xylopyranosyl-(1-->2)-beta-D-xylopyranosyl]-1,7,8-trihydroxy-3-methoxyxanthone (1), 7-O-[alpha-L-rhamnopyranosyl-(1-->2)-beta-D-xylopyranosyl]-1,7,8-trihydroxy-3-methoxyxanthone (2), 8-O-beta-D-glucopyranosyl-1,3,5,8-tetrahydroxyxanthone (3), 1-O-beta-D-glucopyranosyl-1-hydroxy-3,7,8-trimethoxyxanthone (4), 1-O-[beta-D-xylopyranosyl-(1-->6)-beta-D-glucopyranosyl]-1-hydroxy-2,3,5-trimethoxyxanthone (5) and 1-O-[beta-D-xylopyranosyl-(1-->6)-beta-D-glucopyranosyl]-1-hydroxy-3,5-dimethoxyxanthone (6) on the basis of spectroscopic evidence.

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Aim: To investigate the chemical constituents of Cyanotis arachnoidea.

Methods: By using chromatographic methods for separation and combination with spectral analysis, their chemical structures were determined.

Results: Six compounds were identified as ajugasterone C-20, 22-acetonide (1), 20-hydroxyecdysone-20, 22-acetonide (2), 22-oxo-ajugasterone C (3), 22-oxo-20-hydroxyecdysone (4), beta-sitosterol (5), daucosterol (6).

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UV labeling detection has been commonly used to determine the association constants between lectins and saccharides, but the interaction is always between the labeled carbohydrates, rather than the truly underivatized carbohydrates, and lectins. In order to directly detect saccharides during the study on the interaction of glucose and its derivatives with lectins (e.g.

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