Biomedical subjects

Xing-Feng Bao

Publications and source records attributed to Xing-Feng Bao.

3 recordsLinked to original sources

PubMed2002

Structural features of immunologically active polysaccharides from Ganoderma lucidum.

Three polysaccharides, two heteroglycans (PL-1 and PL-4) and one glucan (PL-3), were solubilized from the fruit bodies of Ganoderma lucidum and isolated by anion-exchange and gel-filtration chromatography. Their structural features were elucidated by glycosyl residue and glycosyl linkage composition analyses, partial acid hydrolysis, acetolysis, periodate oxidation, 1D and 2D NMR spectroscopy, and ESI-MS experiments. The data obtained indicated that PL-1 had a backbone consisting of 1,4-linked alpha-D-glucopyranosyl residues and 1,6-linked beta-D-galactopyranosyl residues with branches at O-6 of glucose residues and O-2 of galactose residues, composed of terminal glucose, 1,6-linked glucosyl residues and terminal rhamnose. PL-3 was a highly branched glucan composed of 1,3-linked beta-D-glucopyranosyl residues substituted at O-6 with 1,6-linked glucosyl residues. PL-4 was comprised of 1,3-, 1,4-, 1,6-linked beta-D-glucopyranosyl residues and 1,6-linked beta-D-mannopyranosyl residues. These polysaccharides enhanced the proliferation of T- and B-lymphocytes in vitro to varying contents and PL-1 exhibited an immune-stimulating activity in mice.

Adjuvants, Immunologic↗

PubMed2002

Purification, characterization, and modification of T lymphocyte-stimulating polysaccharide from spores of Ganoderma lucidum.

The hot-water extract of the spores of Ganoderma lucidum was shown to have a stimulating effect on concanavalin A-induced mitogenic activity of T lymphocytes. Bioassay-guided separation led to the isolation of a polysaccharide with potent T lymphocyte-stimulating activity by ethanol fractionation, anion-exchange, and size-exclusion chromatography. Based on the composition and methylation analyses, periodate oxidation, Smith degradation, and NMR spectroscopy, the native polysaccharide was shown to be a beta-D-(1-->3)-glucan with branches of terminal glucosyl residues substituted at C-6 of the glucose residues in the main chain. The branching ratio is approximately 20%. A series of sulfated or carboxymethylated derivatives were prepared and their structural features were elucidated by chemical and spectral analyses. The solution conformation and T lymphocyte proliferation effect of the glucans before and after derivatization were compared and discussed. The data obtained indicate that the introduction of ionic groups would significantly affect the original conformation of the native glucan in aqueous solution and further affect T lymphocyte-stimulating activity. The triple-helical structure of the glucans, the nature of the ionic groups, and the density of negative charge were considered to be closely related to this activity.

Animals↗

PubMed2000

Structure and Conformation Behavior of a Glucan from Spores of Ganoderma lucidum (Fr.) Karst.

A novel polysaccharide designated as beta-D-glucan LB-NB, [alpha](D)(21) -24.52(0)(c =0.81, H(2)O)and Mr 4.7x10(4), was isolated and purified from a 0.5 mol/L sodium hydroxide extract of the sporoderm-broken spores of Ganoderma lucidum. The results of NMR experiments, total hydrolysis, methylation analysis and Smith degradation of LB-NB showed that it possesses a backbone consisting of(1right curved arrow 3)- beta-D-glucosyl residues, about two out of nine glucosyl residues being substituted at O-6 by single glucosyl groups. The conformational behavior of LB-NB was studied. Measurements by specific rotations and viscometry showed that the glucan LB-NB takes an ordered structure in water or lower concentration(<0.05 mol/L)alkaline solution and dissolves as random coil in higher concentration(>0.1 mol/L)alkaline solution or in dimethyl sulfoxide(Me(2)SO). The ordered conformation melts into flexible chains with the increase of the concentration of alkali or the V(DMSO)(v/v)of H(2)O-Me(2)SO mixture. The former dissociation is reversible and the later is irreversible. The complex-formation with Congo red indicated that the LB-NB takes neither triple-stranded helical nor randomly coiled conformation in neutral or slightly alkaline solution, and most probably, it should contain single helical structure in aqueous solution. According to immunological test, the LB-NB showed remarkable activity of stimulating the proliferation of T-Cells in vitro, giving a good example for Kulicke's statement.

Journal Article↗