An apigalacturonan (AGA)-rich polysaccharide, ZCMP, was isolated from the sea grass Zostera caesp... more An apigalacturonan (AGA)-rich polysaccharide, ZCMP, was isolated from the sea grass Zostera caespitosa Miki. The depolymerized fragments derived from ZCMP were obtained by either acidic degradation or pectinase degradation, and their structures were characterized by electrospray ionization collision-induced-dissociation mass spectrometry (ESI-CID-MS 2) and nuclear magnetic resonance (NMR) spectroscopy. The average molecular weight of ZCMP was 77.2 kD and it consisted of galacturonic acid (GalA), apiosefuranose (Api), galactose (Gal), rhamnose (Rha), arabinose (Ara), xylose (Xyl), and mannose (Man), at a molar ratio of 51.4꞉15.5꞉6.0꞉11.8꞉4.2꞉4.4꞉4.2. There were two regions of AGA (70%) and rhamnogalacturonan-I (RG-Ι, 30%) in ZCMP. AGA was composed of an α-1,4-D-galactopyranosyluronan backbone mainly substituted at the O-3 position by single Api residues. RG-Ι possessed a backbone of repeating disaccharide units of →4GalAα1,2Rhaα1→, with a few α-L-arabinose and β-D-galactose residues as side chains. The anti-angiogenesis assay showed that ZCMP inhibited the migratory activity of human umbilical vein endothelial cell (HUVECs), with no influence on endothelial cells growth. ZCMP also promoted macrophage phagocytosis. These findings of the present study OPEN ACCESS Mar. Drugs 2015, 13 3711 demonstrated the potential anti-tumor activity of ZCMP through anti-angiogenic and immunoregulatory pathways.
The red alga, Furcellaria lumbricalis from the coast of the Prince Edward Island (PEI) in Atlanti... more The red alga, Furcellaria lumbricalis from the coast of the Prince Edward Island (PEI) in Atlantic Canada, was extracted with hot water and fractionated with 0.125 M KCl to obtain a carrageenan-like polysaccharide. The polysaccharide was further purified on ion-exchange and gel-permeation chromatography to yield a fraction (FB1) of uniform size and charge, with an average molecular weight of 428 kD. Oligosaccharides generated with acid hydrolysis of FB1 were sequenced using the electrospray ionisation collision induced dissociation tandem mass spectrometry (ES-CID-MS/MS) technique. On the basis of chemical and spectroscopic analysis, FB1 was characterised to be composed of 1,4-linked 3,6-anhydro-galactose (40%), 1,3-linked 4-sulphated-galactose (30%), 1,3-linked galactose (20%), 1,4-linked galactose (8%) and 1,4linked 3-O-methyl-galactose (2%), which makes it be a novel sulphated galactan hybrid. The b-secretase (BACE) inhibition and immunomodulation activities of FB1-derived oligosaccharides were evaluated in vitro.
Oligosaccharides were prepared through mild hydrochloric acid hydrolysis of k-carrageenan from Ka... more Oligosaccharides were prepared through mild hydrochloric acid hydrolysis of k-carrageenan from Kappaphycus striatum carrageenan. Three oligosaccharides were purified by strong-anion exchange high-performance chromatography. Their structure was elucidated using mass spectral and NMR data. Negative-ion electrospray ionization (ESI) mass spectra at different fragmentor voltages provided the molecular weight of the compounds and unraveled the fragmentation pattern of the k-carrageenan oligosaccharides. 2D NMR techniques, including 1 H-1 H COSY, 1 H-1 H TOCSY and 13 C-1 H HMQC, were performed to determine the structure of a trisulfated pentasaccharide. 1D NMR and ESIMS were used to determine the structures of a k-carrageenan-derived pentasaccharide, heptasaccharide, and an undecasaccharide. All the oligosaccharides characterized have a 4-O-sulfo-D-galactopyranose residue at both the reducing and nonreducing ends.
A synthetic pentasaccharide, containing an intact antithrombin III (ATIII) binding site that is i... more A synthetic pentasaccharide, containing an intact antithrombin III (ATIII) binding site that is in clinical studies a specific antifactor Xa agent, serves as a substrate for a heparin lyase (heparinase I, EC 4.2.2.7) from Flavobacterium heparinum. Heparinase I, currently being assessed as a heparin reversal agent, also reverses the antifactor Xa activity of this synthetic pentasaccharide by breaking it down to inactive disaccharide and trisaccharide products. D
International journal of biological macromolecules, Jan 16, 2015
In the present paper, thiourea modified chitosan resin (TMCR) was firstly prepared through conver... more In the present paper, thiourea modified chitosan resin (TMCR) was firstly prepared through converting hydroxyl groups of chitosan resin into thiol groups, using glutaraldehyde as cross-linking agent and thiourea as modification agent. TMCR was characterized by FTIR, EDXS, SEM, XRD and AFM technologies. Batch adsorption experiments were performed to study the adsorption capacity of TMCR for patulin at different pH, temperature, contact time and patulin concentration. The result showed that TMCR was effective in removal of patulin from aqueous solution. The adsorption capacity of TMCR for patulin was 1.0mg/g at pH 4.0, 25°C for 24h. Adsorption process could be well described by pseudo-first order model, Freundlich isotherm model and intraparticle diffusion model. It indicated that TMCR is expected to be a new material for patulin adsorption from aqueous solutions.
In our previous studies, we prepared novel oligomannuronate-chromium(III) complexes (OM2, OM4) fr... more In our previous studies, we prepared novel oligomannuronate-chromium(III) complexes (OM2, OM4) from marine alginate, and found that these compounds sensitize insulin action better than oligomannuronate(OM), chromium, and metformin in C2C12 skeletal muscle cells. In the present study, we studied their effects on mitochondrial biogenesis, lipid metabolism, and the underlying molecular mechanisms in differentiated 3T3-L1 adipocytes. We firstly used the pGL3-PGC1α and pGL3-ATGL promoter plasmids to compare their effects on PGC1α and ATGL transcription activities. Then mitochondrial biogenesis was quantified by transmission electron microscopy and MitoTracker staining. Mitochondrial oxygen consumption and fatty acid oxidation were measured by an oxygen biosensor system and ³H-labelled water scintillation. The mitochondrial DNA and mRNA involved in mitochondrial biogenesis and lipid oxidation were evaluated by real-time PCR. AMPK together with other protein expression levels were measured...
ABSTRACT Myrmekioside A, which was isolated from the marine sponge Myrmekioderma sp. as a member ... more ABSTRACT Myrmekioside A, which was isolated from the marine sponge Myrmekioderma sp. as a member of the family of natural mono-O-alkyl-diglycosylglycerols, and which has a strong reversion effect on the tumor cell morphology of ras-transformed cells at 5 μg/mL, was synthesized for the first time in 17 steps and 14 % overall yield. The β-glycosidic linkages in myrmekioside A were successfully constructed by the neighbouring-group-participation approach using trichloroacetimidates and thioglycosides as glycosyl donors. The 2R absolute configuration at C-2 of the glycerol backbone was derived from (S)-1,2-isopropylideneglycerol (8). This synthetic approach may be applicable to the preparation of other myrmekioside analogues featuring different sugars and alkyl chains for further structure–activity relationship studies.
This study on the effects of low molecular weight chitosan (LMC-1) and shrimp preserving agents s... more This study on the effects of low molecular weight chitosan (LMC-1) and shrimp preserving agents such as phytic acid (PA), sodium bisulfite (SB), and crustacean preservative (CP) on the preservation of shrimp (Trachypenaeus curvirostris) and the bacteriostasis of LMC-1 showed that: (1) Different LMC-1 concentration has different bacteriostasis onE. coli, B. subtilis andS. aureau; (2) LMC-1 and CP are better
An apigalacturonan (AGA)-rich polysaccharide, ZCMP, was isolated from the sea grass Zostera caesp... more An apigalacturonan (AGA)-rich polysaccharide, ZCMP, was isolated from the sea grass Zostera caespitosa Miki. The depolymerized fragments derived from ZCMP were obtained by either acidic degradation or pectinase degradation, and their structures were characterized by electrospray ionization collision-induced-dissociation mass spectrometry (ESI-CID-MS 2 ) and nuclear magnetic resonance (NMR) spectroscopy. The average molecular weight of ZCMP was 77.2 kD and it consisted of galacturonic acid (GalA), apiosefuranose (Api), galactose (Gal), rhamnose (Rha), arabinose (Ara), xylose (Xyl), and mannose (Man), at a molar ratio of 51.4꞉15.5꞉6.0꞉11.8꞉4.2꞉4.4꞉4.2. There were two regions of AGA (70%) and rhamnogalacturonan-I (RG-Ι, 30%) in ZCMP. AGA was composed of an α-1,4-D-galactopyranosyluronan backbone mainly substituted at the O-3 position by single Api residues. RG-Ι possessed a backbone of repeating disaccharide units of →4GalAα1,2Rhaα1→, with a few α-L-arabinose and β-D-galactose residues as side chains. The anti-angiogenesis assay showed that ZCMP inhibited the migratory activity of human umbilical vein endothelial cell (HUVECs), with no influence on endothelial cells growth. ZCMP also promoted macrophage phagocytosis. These findings of the present study
Oligosaccharides were prepared through mild hydrochloric acid hydrolysis of kappa-carrageenan fro... more Oligosaccharides were prepared through mild hydrochloric acid hydrolysis of kappa-carrageenan from Kappaphycus striatum carrageenan. Three oligosaccharides were purified by strong-anion exchange high-performance chromatography. Their structure was elucidated using mass spectral and NMR data. Negative-ion electrospray ionization (ESI) mass spectra at different fragmentor voltages provided the molecular weight of the compounds and unraveled the fragmentation pattern of the kappa-carrageenan oligosaccharides. 2D NMR techniques, including 1H-(1)H COSY, 1H-(1)H TOCSY and 13C-(1)H HMQC, were performed to determine the structure of a trisulfated pentasaccharide. 1D NMR and ESIMS were used to determine the structures of a kappa-carrageenan-derived pentasaccharide, heptasaccharide, and an undecasaccharide. All the oligosaccharides characterized have a 4-O-sulfo-D-galactopyranose residue at both the reducing and nonreducing ends.
Chitosan oligosaccharides (COSs), depolymerized products of chitosan composed of β-(1→4) d-glucos... more Chitosan oligosaccharides (COSs), depolymerized products of chitosan composed of β-(1→4) d-glucosamine units, have broad range of biological activities such as antitumour, antifungal, and antioxidant activities. In this study, peracetylated chitosan oligosaccharides (PACOs) and N-acetylated chitosan oligosaccharides (NACOs) were prepared from the COSs by chemcal modification. The structures of these monomers were identified using NMR and ESI-MS spectra. Their antagonist effects against glutamate-induced PC12 cell death were investigated. The results showed that pretreatment of PC12 cells with the PACOs markedly inhibited glutamate-induced cell death in a concentration-dependent manner. The PACOs were better glutamate antagonists compared to the COSs and the NACOs, suggesting the peracetylation is essential for the neuroprotective effects of chitosan oligosaccharides. In addition, the PACOs pretreatment significantly reduced lactate dehydrogenase release and reactive oxygen species p...
A rapid method of microwave assisted acid hydrolysis was established to prepare κ-carra-oligosacc... more A rapid method of microwave assisted acid hydrolysis was established to prepare κ-carra-oligosaccharides. The optimal hydrolysis condition was determined by an orthogonal test. The degree of polymerization (DP) of oligosaccharides was detected by high performance thin layer chromatography (HPTLC) and polyacrylamide gel electrophoresis (PAGE). Considering the results of HPTLC and PAGE, the optimum condition of microwave assisted acid hydrolysis was determined. The concentration of κ-carrageenan was 5 mg mL −1 ; the reaction solution was adjusted to pH 3 with diluted hydrochloric acid; the solution was hydrolyzed under microwave irradiation at 100 for 15 ℃ min. Oligosaccharides were separated by a Superdex 30 column (2.6 cm × 90 cm) using AKTA Purifier UPC100 and detected with an online refractive index detector. Each fraction was characterized by electrospray ionization mass spectrometry (ESI-MS). The data showed that odd-numbered κ-carra-oligosaccharides with DP ranging from 3 to 21 could be obtained with this method, and the structures of the oligosaccharides were consistent with those obtained by traditional mild acid hydrolysis. The new method was more convenient, efficient and environment-friendly than traditional mild acid hydrolysis. Our results provided a useful reference for the preparation of oligosaccharides from other polysaccharides.
Se pu = Chinese journal of chromatography / Zhongguo hua xue hui, 2007
The high performance gel permeation chromatographic (HPGPC) behaviors of four beta-1, 3/1, 6-gluc... more The high performance gel permeation chromatographic (HPGPC) behaviors of four beta-1, 3/1, 6-glucans (GF1, GF2, GF3, GF4) with different protein contents and one alpha-1, 4/1, 6-glucan (P100) from Grifola frondosa were examined with different concentrations of NaCl solution and pH values. The experimental results showed that the relative molecular mass (M(r)) of the beta-glucans sharply dropped as the NaCl concentration was less than 0.025 mol/L and then tended to be stable as the NaCl concentration was raised from 0.1 to 0.2 mol/L, the M(r) increased quickly from pH 3 to 6, and then maintained stable from pH 6 to 9, but slightly increased as the pH value was higher than 9. However, the M(r) of the alpha-1, 4/1, 6-glucan was slightly affected by either different concentrations of NaCl or different pH values. The beta-glucan existed in a super-helix structure in aqueous solution, which could be influenced by the NaCl concentration and pH value. These factors led to the different mole...
Cordyceps is a rare and exotic mushroom that grows out of the head of a mummified caterpillar. Ma... more Cordyceps is a rare and exotic mushroom that grows out of the head of a mummified caterpillar. Many companies are cultivating Cordyceps to meet the increased demand for its medicinal applications. However, the structures and functions of polysaccharides, one of the pharmaceutical active ingredients in Cordyceps, are difficult to reproduce in vitro. We hypothesized that mimicking the salty environment inside caterpillar bodies might make the cultured fungus synthesize polysaccharides with similar structures and functions to that of wild Cordyceps. By adding either sodium sulfate or sodium chloride into growth media, we observed the salinity-induced anti-angiogenesis activities of the polysaccharides purified from the cultured C. Militaris. To correlate the activities with the polysaccharide structures, we performed the 13 C-NMR analysis and observed profound structural changes including different proportions of a and b glycosidic bonds and appearances of uronic acid signals in the polysaccharides purified from the culture after the salts were added. By coupling the techniques of stable 34 S-sulfate isotope labeling, aniline-and D 5 -aniline tagging, and stable isotope facilitated uronic acid-reduction with LC-MS analysis, our data revealed for the first time the existence of covalently linked sulfate and the presence of polygalacuronic acids in the polysaccharides purified from the salt added C. Militaris culture. Our data showed that culturing C. Militaris with added salts changed the biosynthetic scheme and resulted in novel polysaccharide structures and functions. These findings might be insightful in terms of how to make C. Militaris cultures to reach or to exceed the potency of wild Cordyceps in future.
Glucans are polymers of D-glucose with differing linkages in linear or branched sequences. They a... more Glucans are polymers of D-glucose with differing linkages in linear or branched sequences. They are constituents of microbial and plant cell-walls and involved in important bio-recognition processes, including immunomodulation, anticancer activities, pathogen virulence, and plant cellwall biodegradation. Translational possibilities for these activities in medicine and biotechnology are considerable. High-throughput micro-methods are needed to screen proteins for recognition of specific glucan sequences as a lead to structure-function studies and their exploitation. We describe construction of a "glucome" microarray, the first sequence-defined glycome-scale microarray, using a "designer" approach from targeted ligand-bearing glucans in conjunction with a novel high-sensitivity mass spectrometric sequencing method, as a screening tool to assign glucan recognition motifs. The glucome microarray comprises 153 oligosaccharide probes with high purity, representing major sequences in glucans. Negative-ion electrospray tandem mass spectrometry with collision-induced dissociation was used for complete linkage analysis of gluco-oligosaccharides in linear "homo" and "hetero" and branched sequences. The system is validated using antibodies and carbohydrate-binding modules known to target ␣or -glucans in different biological contexts, extending knowledge on their specificities, and applied to reveal new information on glucan recognition by two signaling molecules of the immune system against pathogens:
An apigalacturonan (AGA)-rich polysaccharide, ZCMP, was isolated from the sea grass Zostera caesp... more An apigalacturonan (AGA)-rich polysaccharide, ZCMP, was isolated from the sea grass Zostera caespitosa Miki. The depolymerized fragments derived from ZCMP were obtained by either acidic degradation or pectinase degradation, and their structures were characterized by electrospray ionization collision-induced-dissociation mass spectrometry (ESI-CID-MS 2) and nuclear magnetic resonance (NMR) spectroscopy. The average molecular weight of ZCMP was 77.2 kD and it consisted of galacturonic acid (GalA), apiosefuranose (Api), galactose (Gal), rhamnose (Rha), arabinose (Ara), xylose (Xyl), and mannose (Man), at a molar ratio of 51.4꞉15.5꞉6.0꞉11.8꞉4.2꞉4.4꞉4.2. There were two regions of AGA (70%) and rhamnogalacturonan-I (RG-Ι, 30%) in ZCMP. AGA was composed of an α-1,4-D-galactopyranosyluronan backbone mainly substituted at the O-3 position by single Api residues. RG-Ι possessed a backbone of repeating disaccharide units of →4GalAα1,2Rhaα1→, with a few α-L-arabinose and β-D-galactose residues as side chains. The anti-angiogenesis assay showed that ZCMP inhibited the migratory activity of human umbilical vein endothelial cell (HUVECs), with no influence on endothelial cells growth. ZCMP also promoted macrophage phagocytosis. These findings of the present study OPEN ACCESS Mar. Drugs 2015, 13 3711 demonstrated the potential anti-tumor activity of ZCMP through anti-angiogenic and immunoregulatory pathways.
The red alga, Furcellaria lumbricalis from the coast of the Prince Edward Island (PEI) in Atlanti... more The red alga, Furcellaria lumbricalis from the coast of the Prince Edward Island (PEI) in Atlantic Canada, was extracted with hot water and fractionated with 0.125 M KCl to obtain a carrageenan-like polysaccharide. The polysaccharide was further purified on ion-exchange and gel-permeation chromatography to yield a fraction (FB1) of uniform size and charge, with an average molecular weight of 428 kD. Oligosaccharides generated with acid hydrolysis of FB1 were sequenced using the electrospray ionisation collision induced dissociation tandem mass spectrometry (ES-CID-MS/MS) technique. On the basis of chemical and spectroscopic analysis, FB1 was characterised to be composed of 1,4-linked 3,6-anhydro-galactose (40%), 1,3-linked 4-sulphated-galactose (30%), 1,3-linked galactose (20%), 1,4-linked galactose (8%) and 1,4linked 3-O-methyl-galactose (2%), which makes it be a novel sulphated galactan hybrid. The b-secretase (BACE) inhibition and immunomodulation activities of FB1-derived oligosaccharides were evaluated in vitro.
Oligosaccharides were prepared through mild hydrochloric acid hydrolysis of k-carrageenan from Ka... more Oligosaccharides were prepared through mild hydrochloric acid hydrolysis of k-carrageenan from Kappaphycus striatum carrageenan. Three oligosaccharides were purified by strong-anion exchange high-performance chromatography. Their structure was elucidated using mass spectral and NMR data. Negative-ion electrospray ionization (ESI) mass spectra at different fragmentor voltages provided the molecular weight of the compounds and unraveled the fragmentation pattern of the k-carrageenan oligosaccharides. 2D NMR techniques, including 1 H-1 H COSY, 1 H-1 H TOCSY and 13 C-1 H HMQC, were performed to determine the structure of a trisulfated pentasaccharide. 1D NMR and ESIMS were used to determine the structures of a k-carrageenan-derived pentasaccharide, heptasaccharide, and an undecasaccharide. All the oligosaccharides characterized have a 4-O-sulfo-D-galactopyranose residue at both the reducing and nonreducing ends.
A synthetic pentasaccharide, containing an intact antithrombin III (ATIII) binding site that is i... more A synthetic pentasaccharide, containing an intact antithrombin III (ATIII) binding site that is in clinical studies a specific antifactor Xa agent, serves as a substrate for a heparin lyase (heparinase I, EC 4.2.2.7) from Flavobacterium heparinum. Heparinase I, currently being assessed as a heparin reversal agent, also reverses the antifactor Xa activity of this synthetic pentasaccharide by breaking it down to inactive disaccharide and trisaccharide products. D
International journal of biological macromolecules, Jan 16, 2015
In the present paper, thiourea modified chitosan resin (TMCR) was firstly prepared through conver... more In the present paper, thiourea modified chitosan resin (TMCR) was firstly prepared through converting hydroxyl groups of chitosan resin into thiol groups, using glutaraldehyde as cross-linking agent and thiourea as modification agent. TMCR was characterized by FTIR, EDXS, SEM, XRD and AFM technologies. Batch adsorption experiments were performed to study the adsorption capacity of TMCR for patulin at different pH, temperature, contact time and patulin concentration. The result showed that TMCR was effective in removal of patulin from aqueous solution. The adsorption capacity of TMCR for patulin was 1.0mg/g at pH 4.0, 25°C for 24h. Adsorption process could be well described by pseudo-first order model, Freundlich isotherm model and intraparticle diffusion model. It indicated that TMCR is expected to be a new material for patulin adsorption from aqueous solutions.
In our previous studies, we prepared novel oligomannuronate-chromium(III) complexes (OM2, OM4) fr... more In our previous studies, we prepared novel oligomannuronate-chromium(III) complexes (OM2, OM4) from marine alginate, and found that these compounds sensitize insulin action better than oligomannuronate(OM), chromium, and metformin in C2C12 skeletal muscle cells. In the present study, we studied their effects on mitochondrial biogenesis, lipid metabolism, and the underlying molecular mechanisms in differentiated 3T3-L1 adipocytes. We firstly used the pGL3-PGC1α and pGL3-ATGL promoter plasmids to compare their effects on PGC1α and ATGL transcription activities. Then mitochondrial biogenesis was quantified by transmission electron microscopy and MitoTracker staining. Mitochondrial oxygen consumption and fatty acid oxidation were measured by an oxygen biosensor system and ³H-labelled water scintillation. The mitochondrial DNA and mRNA involved in mitochondrial biogenesis and lipid oxidation were evaluated by real-time PCR. AMPK together with other protein expression levels were measured...
ABSTRACT Myrmekioside A, which was isolated from the marine sponge Myrmekioderma sp. as a member ... more ABSTRACT Myrmekioside A, which was isolated from the marine sponge Myrmekioderma sp. as a member of the family of natural mono-O-alkyl-diglycosylglycerols, and which has a strong reversion effect on the tumor cell morphology of ras-transformed cells at 5 μg/mL, was synthesized for the first time in 17 steps and 14 % overall yield. The β-glycosidic linkages in myrmekioside A were successfully constructed by the neighbouring-group-participation approach using trichloroacetimidates and thioglycosides as glycosyl donors. The 2R absolute configuration at C-2 of the glycerol backbone was derived from (S)-1,2-isopropylideneglycerol (8). This synthetic approach may be applicable to the preparation of other myrmekioside analogues featuring different sugars and alkyl chains for further structure–activity relationship studies.
This study on the effects of low molecular weight chitosan (LMC-1) and shrimp preserving agents s... more This study on the effects of low molecular weight chitosan (LMC-1) and shrimp preserving agents such as phytic acid (PA), sodium bisulfite (SB), and crustacean preservative (CP) on the preservation of shrimp (Trachypenaeus curvirostris) and the bacteriostasis of LMC-1 showed that: (1) Different LMC-1 concentration has different bacteriostasis onE. coli, B. subtilis andS. aureau; (2) LMC-1 and CP are better
An apigalacturonan (AGA)-rich polysaccharide, ZCMP, was isolated from the sea grass Zostera caesp... more An apigalacturonan (AGA)-rich polysaccharide, ZCMP, was isolated from the sea grass Zostera caespitosa Miki. The depolymerized fragments derived from ZCMP were obtained by either acidic degradation or pectinase degradation, and their structures were characterized by electrospray ionization collision-induced-dissociation mass spectrometry (ESI-CID-MS 2 ) and nuclear magnetic resonance (NMR) spectroscopy. The average molecular weight of ZCMP was 77.2 kD and it consisted of galacturonic acid (GalA), apiosefuranose (Api), galactose (Gal), rhamnose (Rha), arabinose (Ara), xylose (Xyl), and mannose (Man), at a molar ratio of 51.4꞉15.5꞉6.0꞉11.8꞉4.2꞉4.4꞉4.2. There were two regions of AGA (70%) and rhamnogalacturonan-I (RG-Ι, 30%) in ZCMP. AGA was composed of an α-1,4-D-galactopyranosyluronan backbone mainly substituted at the O-3 position by single Api residues. RG-Ι possessed a backbone of repeating disaccharide units of →4GalAα1,2Rhaα1→, with a few α-L-arabinose and β-D-galactose residues as side chains. The anti-angiogenesis assay showed that ZCMP inhibited the migratory activity of human umbilical vein endothelial cell (HUVECs), with no influence on endothelial cells growth. ZCMP also promoted macrophage phagocytosis. These findings of the present study
Oligosaccharides were prepared through mild hydrochloric acid hydrolysis of kappa-carrageenan fro... more Oligosaccharides were prepared through mild hydrochloric acid hydrolysis of kappa-carrageenan from Kappaphycus striatum carrageenan. Three oligosaccharides were purified by strong-anion exchange high-performance chromatography. Their structure was elucidated using mass spectral and NMR data. Negative-ion electrospray ionization (ESI) mass spectra at different fragmentor voltages provided the molecular weight of the compounds and unraveled the fragmentation pattern of the kappa-carrageenan oligosaccharides. 2D NMR techniques, including 1H-(1)H COSY, 1H-(1)H TOCSY and 13C-(1)H HMQC, were performed to determine the structure of a trisulfated pentasaccharide. 1D NMR and ESIMS were used to determine the structures of a kappa-carrageenan-derived pentasaccharide, heptasaccharide, and an undecasaccharide. All the oligosaccharides characterized have a 4-O-sulfo-D-galactopyranose residue at both the reducing and nonreducing ends.
Chitosan oligosaccharides (COSs), depolymerized products of chitosan composed of β-(1→4) d-glucos... more Chitosan oligosaccharides (COSs), depolymerized products of chitosan composed of β-(1→4) d-glucosamine units, have broad range of biological activities such as antitumour, antifungal, and antioxidant activities. In this study, peracetylated chitosan oligosaccharides (PACOs) and N-acetylated chitosan oligosaccharides (NACOs) were prepared from the COSs by chemcal modification. The structures of these monomers were identified using NMR and ESI-MS spectra. Their antagonist effects against glutamate-induced PC12 cell death were investigated. The results showed that pretreatment of PC12 cells with the PACOs markedly inhibited glutamate-induced cell death in a concentration-dependent manner. The PACOs were better glutamate antagonists compared to the COSs and the NACOs, suggesting the peracetylation is essential for the neuroprotective effects of chitosan oligosaccharides. In addition, the PACOs pretreatment significantly reduced lactate dehydrogenase release and reactive oxygen species p...
A rapid method of microwave assisted acid hydrolysis was established to prepare κ-carra-oligosacc... more A rapid method of microwave assisted acid hydrolysis was established to prepare κ-carra-oligosaccharides. The optimal hydrolysis condition was determined by an orthogonal test. The degree of polymerization (DP) of oligosaccharides was detected by high performance thin layer chromatography (HPTLC) and polyacrylamide gel electrophoresis (PAGE). Considering the results of HPTLC and PAGE, the optimum condition of microwave assisted acid hydrolysis was determined. The concentration of κ-carrageenan was 5 mg mL −1 ; the reaction solution was adjusted to pH 3 with diluted hydrochloric acid; the solution was hydrolyzed under microwave irradiation at 100 for 15 ℃ min. Oligosaccharides were separated by a Superdex 30 column (2.6 cm × 90 cm) using AKTA Purifier UPC100 and detected with an online refractive index detector. Each fraction was characterized by electrospray ionization mass spectrometry (ESI-MS). The data showed that odd-numbered κ-carra-oligosaccharides with DP ranging from 3 to 21 could be obtained with this method, and the structures of the oligosaccharides were consistent with those obtained by traditional mild acid hydrolysis. The new method was more convenient, efficient and environment-friendly than traditional mild acid hydrolysis. Our results provided a useful reference for the preparation of oligosaccharides from other polysaccharides.
Se pu = Chinese journal of chromatography / Zhongguo hua xue hui, 2007
The high performance gel permeation chromatographic (HPGPC) behaviors of four beta-1, 3/1, 6-gluc... more The high performance gel permeation chromatographic (HPGPC) behaviors of four beta-1, 3/1, 6-glucans (GF1, GF2, GF3, GF4) with different protein contents and one alpha-1, 4/1, 6-glucan (P100) from Grifola frondosa were examined with different concentrations of NaCl solution and pH values. The experimental results showed that the relative molecular mass (M(r)) of the beta-glucans sharply dropped as the NaCl concentration was less than 0.025 mol/L and then tended to be stable as the NaCl concentration was raised from 0.1 to 0.2 mol/L, the M(r) increased quickly from pH 3 to 6, and then maintained stable from pH 6 to 9, but slightly increased as the pH value was higher than 9. However, the M(r) of the alpha-1, 4/1, 6-glucan was slightly affected by either different concentrations of NaCl or different pH values. The beta-glucan existed in a super-helix structure in aqueous solution, which could be influenced by the NaCl concentration and pH value. These factors led to the different mole...
Cordyceps is a rare and exotic mushroom that grows out of the head of a mummified caterpillar. Ma... more Cordyceps is a rare and exotic mushroom that grows out of the head of a mummified caterpillar. Many companies are cultivating Cordyceps to meet the increased demand for its medicinal applications. However, the structures and functions of polysaccharides, one of the pharmaceutical active ingredients in Cordyceps, are difficult to reproduce in vitro. We hypothesized that mimicking the salty environment inside caterpillar bodies might make the cultured fungus synthesize polysaccharides with similar structures and functions to that of wild Cordyceps. By adding either sodium sulfate or sodium chloride into growth media, we observed the salinity-induced anti-angiogenesis activities of the polysaccharides purified from the cultured C. Militaris. To correlate the activities with the polysaccharide structures, we performed the 13 C-NMR analysis and observed profound structural changes including different proportions of a and b glycosidic bonds and appearances of uronic acid signals in the polysaccharides purified from the culture after the salts were added. By coupling the techniques of stable 34 S-sulfate isotope labeling, aniline-and D 5 -aniline tagging, and stable isotope facilitated uronic acid-reduction with LC-MS analysis, our data revealed for the first time the existence of covalently linked sulfate and the presence of polygalacuronic acids in the polysaccharides purified from the salt added C. Militaris culture. Our data showed that culturing C. Militaris with added salts changed the biosynthetic scheme and resulted in novel polysaccharide structures and functions. These findings might be insightful in terms of how to make C. Militaris cultures to reach or to exceed the potency of wild Cordyceps in future.
Glucans are polymers of D-glucose with differing linkages in linear or branched sequences. They a... more Glucans are polymers of D-glucose with differing linkages in linear or branched sequences. They are constituents of microbial and plant cell-walls and involved in important bio-recognition processes, including immunomodulation, anticancer activities, pathogen virulence, and plant cellwall biodegradation. Translational possibilities for these activities in medicine and biotechnology are considerable. High-throughput micro-methods are needed to screen proteins for recognition of specific glucan sequences as a lead to structure-function studies and their exploitation. We describe construction of a "glucome" microarray, the first sequence-defined glycome-scale microarray, using a "designer" approach from targeted ligand-bearing glucans in conjunction with a novel high-sensitivity mass spectrometric sequencing method, as a screening tool to assign glucan recognition motifs. The glucome microarray comprises 153 oligosaccharide probes with high purity, representing major sequences in glucans. Negative-ion electrospray tandem mass spectrometry with collision-induced dissociation was used for complete linkage analysis of gluco-oligosaccharides in linear "homo" and "hetero" and branched sequences. The system is validated using antibodies and carbohydrate-binding modules known to target ␣or -glucans in different biological contexts, extending knowledge on their specificities, and applied to reveal new information on glucan recognition by two signaling molecules of the immune system against pathogens:
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Papers by Guangli Yu