Neuraminidase (NA) cleaves the glycosidic bond linkages of sialic acids to release the mature virions from infected cells and has been an attractive therapeutic target for anti-influenza agents. In our ongoing investigation of NA inhibitors in mushroom extracts, we found that the extract the fruiting body of Glaziella splendens potently inhibited neuraminidase. The fruiting bodies of G. splendens were extracted and partitioned successively with hexane, ethyl acetate, and butanol. The ethyl acetate soluble-layer was subjected to silica gel and Sephadex LH-20 column chromatographies, and MPLC to obtain five compounds (1–5). Their structures were determined by spectroscopic methods. NA inhibitory activity of these compounds was evaluated using NAs from recombinant rvH1N1, H3N2, and H5N1 influenza A viruses. One compound (1) was elucidated as a new azaphilone derivative, and four compounds (2–5) were identified as entonaemin A, comazaphilone D, rubiginosin A, and entonaemin B, respectively. Compounds 3 and 4 showed considerable inhibitory activity against three types of neuraminidases with the IC₅₀ values of 30.9, 41.8, and 35.7 µM for 3 and 46.5, 50.4, and 29.9 µM for 4, respectively. This study reveals that the fruiting bodies of G. splendens possess azaphilone derivatives with the NA inhibitory activity. This is the first report on the isolation of neuraminidase inhibitors from the fruiting bodies of G. splendens.
Agaricales ; Chromatography ; Fruit ; Influenza A virus ; N-Acetylneuraminic Acid ; Neuraminidase ; Sialic Acids ; Silica Gel ; Virion

Neural cell adhesion molecule (NCAM) is a glycoprotein expressing on the surface of neurons, glial cells, bone cells and natural killer cells. NCAM plays an important role in the process of cell - cell adhesion and cell migration, and is also a model protein to study polysialic acid. In this paper, NCAM gene from mouse mammary gland cells (NMuMG) was cloned into eukaryotic expression vectors pcDNA3.1(+) and transfected into mutant Chinese hamster ovary cells ldlD-14. The stable transfection over-expressing NCAM was obtained through the G418 selection and confirmed by Western blotting. Due to unique characters of ldlD-14 cells, carbohydrate chain of NCAM molecule can be easily manipulated with or without adding galactose in the serum free medium, and this modification can provide the basis for further studies on the effect of glycosylation on NCAM molecular function.
Animals ; CHO Cells ; Cloning, Molecular ; Cricetinae ; Cricetulus ; Female ; Galactose ; Glycosylation ; Mammary Glands, Animal ; cytology ; Mice ; Neural Cell Adhesion Molecules ; biosynthesis ; Polysaccharides ; chemistry ; Sialic Acids ; chemistry ; Transfection

The binding of microorganisms to platelets is a critical step in the development of infective endocarditis. In Streptococcus gordonii, this binding is mediated in part by serine-rich repeat proteins, which interact directly with sialic acid residues located on GPIIb receptors in the platelet membrane. In this study, we found that S. gordonii DL1 strain binds to platelets through bridging between sialic acid residue of fibronectin and serine-rich repeat protein (Hsa). Pretreatment of fibronectin with sialidases specific for alpha(2-3)-linked sialic acids was shown to significantly inhibit binding of the DL1 strain and the binding region(BR) of Hsa protein. Similarly, pre-incubation of bacteria or BR of Hsa with alpha(2-3)-sialyl-N-acetyllactosamine blocked fibronectin binding in the DL1 strain, but not the M99 strain. Together, these data show that the alpha(2-3)-sialic acid residues of fibronectin play an important role in the binding of S. gordonii DL1 to fibronectin through interactions with the Hsa receptor. This interaction is thought to play an important role in the development of pathogenic endocarditis, and may represent an important therapeutic target for the treatment of infective endocarditis.
Bacteria ; Blood Platelets ; Endocarditis ; Etorphine ; Fibronectins* ; Membrane Glycoproteins* ; Membranes ; N-Acetylneuraminic Acid* ; Sialic Acids ; Streptococcus gordonii*

PURPOSE: Cell transplantation of myelin-producing exogenous cells is being extensively explored as a means of remyelinating axons in X-linked adrenoleukodystrophy. We determined whether 3,3',5-Triiodo-L-thyronine (T3) overexpresses the ABCD2 gene in the polysialylated (PSA) form of neural cell adhesion molecule (NCAM)-positive cells and promotes cell proliferation and favors oligodendrocyte lineage differentiation. MATERIALS AND METHODS: PSA-NCAM+ cells from newborn Sprague-Dawley rats were grown for five days on uncoated dishes in defined medium with or without supplementation of basic fibroblast growth factor (bFGF) and/or T3. Then, PSA-NCAM+ spheres were prepared in single cells and transferred to polyornithine/fibronectin-coated glass coverslips for five days to determine the fate of the cells according to the supplementation of these molecules. T3 responsiveness of ABCD2 was analyzed using real-time quantitative polymerase chain reaction, the growth and fate of cells were determined using 5-bromo-2-deoxyuridine incorporation and immunocytochemistry, respectively. RESULTS: Results demonstrated that T3 induces overexpression of the ABCD2 gene in PSA-NCAM+ cells, and can enhance PSA-NCAM+ cell growth in the presence of bFGF, favoring an oligodendrocyte fate. CONCLUSION: These results may provide new insights into investigation of PSA-NCAM+ cells for therapeutic application to X-linked adrenoleukodystrophy.
ATP-Binding Cassette Transporters/*metabolism ; Adrenoleukodystrophy/genetics/*therapy ; Animals ; Animals, Newborn ; Bromodeoxyuridine ; Cell Differentiation ; Fibroblast Growth Factor 2/pharmacology ; Fibronectins/metabolism ; Immunohistochemistry ; Neural Cell Adhesion Molecules/*genetics ; Rats ; Rats, Sprague-Dawley ; Real-Time Polymerase Chain Reaction ; Sialic Acids/metabolism ; Stem Cells ; Thyroid Hormones/*metabolism ; Triiodothyronine/pharmacology

Abnormal glycosylation due to dysregulated glycosyltransferases and glycosidases is a key phenomenon of many malignancies, including colorectal cancer (CRC). In particular, increased ST6 Gal I (beta-galactoside alpha 2, 6 sialyltransferase) and subsequently elevated levels of cell-surface alpha 2, 6-linked sialic acids have been associated with metastasis and therapeutic failure in CRC. As many CRC patients experience metastasis to the liver or lung and fail to respond to curative therapies, intensive research efforts have sought to identify the molecular changes underlying CRC metastasis. ST6 Gal I has been shown to facilitate CRC metastasis, and we believe that additional investigations into the involvement of ST6 Gal I in CRC could facilitate the development of new diagnostic and therapeutic targets. This review summarizes how ST6 Gal I has been implicated in the altered expression of sialylated glycoproteins, which have been linked to CRC metastasis, radioresistance, and chemoresistance.
Antigens, CD/*metabolism ; Colorectal Neoplasms/*metabolism/pathology/*therapy ; Drug Resistance, Neoplasm ; Glycoproteins/*metabolism ; Humans ; Liver Neoplasms/secondary ; Lung Neoplasms/secondary ; Radiation Tolerance ; Receptor, Epidermal Growth Factor/metabolism ; Sialic Acids/*metabolism ; Sialyltransferases/*metabolism

OBJECTIVETo study the effects of Compound Fujian Tablet (FJT)on the neurotization in the cerebral infarction rats and to explore its mechanisms for promoting the motor skills.

METHODSTotally 90 Wistar rats were randomly divided into the drug group, the model group, and the sham-operation group, 30 in each group. The rat model of middle cerebral artery occlusion (MCAO) was successfully established by electrocoagulation. Six hours after successful modeling, the rats of the drug group were orally administered with 9 g/kg FJT water solution, and the other groups were orally administered with equal volume of normal saline, once a day for two weeks. The motor skills of rats were examined by beam walking test. The expressions of nestin, polysialic acid neural cell adhesion molecule (PSA-NCAM), microtubule-associated protein 2 (MAP-2), growth-associated protein (GAP-43), and synaptophysin (Syn) in the brain tissue around the infarction were observed by in immunohistochemical assay. The mean staining gray or the optical density value were detected.

RESULTSThe 86 rats were recruited in the result analysis. After two weeks of administration, the neural function scoring was obviously higher in the drug group than in the model group with statistical difference (P < 0.01). The expressions of nestin, PSA-NCAM, MAP-2, GAP-43, and Syn in the brain tissue around the infarction were more obviously enhanced in the drug group than in the model group, showing statistical difference (P < 0.01).

CONCLUSIONFJT can promote neurotization and improve the motor skill recovery after cerebral infarction.

Animals ; Brain ; metabolism ; pathology ; Cerebral Infarction ; rehabilitation ; Drugs, Chinese Herbal ; therapeutic use ; GAP-43 Protein ; metabolism ; Male ; Microtubule-Associated Proteins ; metabolism ; Motor Skills ; drug effects ; Nerve Regeneration ; Nestin ; metabolism ; Neural Cell Adhesion Molecule L1 ; metabolism ; Phytotherapy ; Rats ; Rats, Wistar ; Sialic Acids ; metabolism ; Synaptophysin ; metabolism

OBJECTIVEBoth the 2, 6 linkage and its topology on target cells are critical for the recognition by human influenza virus. The binding preference of avian flu virus H5N1 HA to the 2, 3-linked sialylated glycans is considered the major factor limiting its efficient infection and transmission in humans. To monitor potential adaptation of H5N1 virus in human population, the surveillance of receptor-binding specificity was undertaken in China.

METHODSThe binding specificity of 32 human H5N1 virus strains isolated from 2003 to 2009 was tested by 2, 3-specific sialidase-treated chicken red blood cell (CRBC) agglutination assay and a solid-phase direct binding assay with synthetic sialylglycopolymers.

RESULTSDual binding preference to 2, 3 and 2, 6-glycans were found in two strains: A/Guangdong/1/06 (A/GD/1/06) and A/Guangxi/1/08 (A/GX/1/08). Though minor effect of short-2, 6-binding was detected in A/GX/1/08 at a low virus titer, both showed high affinity to the oligosaccharide at a high load. Notably both are of the long-2, 6-recognition, with the same topology as that of human H1N1 and H3N2 viruses.

CONCLUSIONThe findings suggest that human H5N1 virus in China likely acquired the potential human-adaptation ability. Further research and surveillance on receptor-binding specificity of H5N1 viruses are required.

Adaptation, Biological ; Animals ; Chickens ; China ; epidemiology ; Hemagglutination Tests ; Humans ; Influenza A Virus, H1N1 Subtype ; metabolism ; Influenza, Human ; epidemiology ; Polysaccharides ; metabolism ; Receptors, Cell Surface ; metabolism ; Receptors, Virus ; metabolism ; Sialic Acids ; metabolism

The primary determinant of influenza virus infectivity is the type of linkage between sialic acid and oligosaccharides on the host cells. Hemagglutinin of avian influenza viruses preferentially binds to sialic acids linked to galactose by an alpha-2,3 linkage whereas hemagglutinin of human influenza viruses binds to sialic acids with an alpha-2,6 linkage. The distribution patterns of influenza receptors in the avian respiratory tracts are of particular interest because these are important for initial viral attachment, replication, and transmission to other species. In this study, we examined the distribution patterns of influenza receptors in the respiratory tract of chickens, ducks, pheasants, and quails because these species have been known to act as intermediate hosts in interspecies transmission. Lectin histochemistry was performed to detect receptor-bearing cells. Cell-specific distribution of the receptors was determined and expression densities were compared. We observed species-, site-, and cell-specific variations in receptor expression. In general, receptor expression was the highest in quails and lowest in ducks. Pheasants and quails had abundant expression of both types of receptors throughout the respiratory tract. These results indicate that pheasants and quails may play important roles as intermediate hosts for the generation of influenza viruses with pandemic potential.
Animals ; Cell Membrane/metabolism/virology ; Hemagglutinin Glycoproteins, Influenza Virus/metabolism ; Host-Pathogen Interactions ; Influenza A virus/*metabolism ; Influenza in Birds/metabolism/transmission ; Lectins/metabolism ; Poultry/metabolism/*virology ; Poultry Diseases/metabolism ; Receptors, Cell Surface/analysis/chemistry/metabolism ; Receptors, Virus/*analysis/metabolism ; Respiratory System/*chemistry ; Sialic Acids/metabolism ; Species Specificity ; Specific Pathogen-Free Organisms

OBJECTIVETo observe the change in the amount of sialic acids on hepatocellular carcinoma (HCC) cell membrane.

METHODSSurgical specimens of HCC and liver cirrhosis tissues were obtained from 28 patients to prepare carcinoma cell and hepatocyte suspensions by collagenase digestion. For assay of α2, 3 and α2, 6-sialic acids, the cells were suspended in the staining buffer containing either fluorescein isothiocyanate-Maackia amurensis lectin (FITC-MAL) or fluorescein isothiocyanate-Sambucus nigra bark lectin (FITC-SNA) and incubated for 1 h, respectively. Flow cytometric analysis was carried out to measure the mean fluorescence intensity (MFI) on the cell surface.

RESULTSIn both FITC-MAL- and FITC-SNA-incubated HCC cells, the MFI on the cell surface was greater than that of the hepatocytes.

CONCLUSIONBoth of α2, 3 and α2, 6- sialic acids increases significantly on the hepatocyte membrane after the carcinomatous change.

Carcinoma, Hepatocellular ; metabolism ; pathology ; Cell Membrane ; metabolism ; Humans ; Liver Cirrhosis ; metabolism ; pathology ; Liver Neoplasms ; metabolism ; pathology ; Sialic Acids ; metabolism

OBJECTIVETo investigate the changes of neural stem cells (NSCs) in the rat hippocampus after cerebral infarction (CI) and to evaluate the neurogenesis caused by the activation of NSCs.

METHODSCI models of rats were made and rats were assigned to 6 groups: sham-operated, 1 day, 3 days, 7 days, 14 days, and 28 days after CI. The dynamic expression of bromodeoxyuridine (BrdU), polysialylated neural cell adhesion molecule (PSA-NCAM), glial fibrillary acidic protein (GFAP), and neuronal nuclear antigen (NeuN) were determined by immunohistochemistry and immunofluorescence staining. BrdU was used to mark the proliferated NSCs. PSA-NCAM was used to mark the plasticity of activated NSCs. GFAP and NeuN were used to mark the differentiated NSCs.

RESULTSCompared with the controls, the number of BrdU+ cells in the hippocampus increased significantly at 1 day after CI (P < 0.05), reached peak at 7 days after CI (P < 0.05), decreased but still elevated compared with the controls at 14 days after CI (P < 0.05), and nearly unchanged at 28 days after CI. The number of BrdU+/PSA-NCAM+ cells increased significantly at 7 days after CI (P < 0.05), reached peak at 14 days after CI (P < 0.05), and decreased but still elevated compared with the controls at 28 days after CI (P < 0.05). The number of BrdU+/PSA-NCAM+ cells was equal to 60% of the number of BrdU+ cells in all the same period. The number of BrdU+/NeuN+ cells in the hippocampus increased significantly at 14 days after CI (P < 0.05) and reached peak at 28 day after CI (P < 0.05). The number of BrdU+/GFAP+ cells in the hippocampus nearly unchanged after CI.

CONCLUSIONCI can stimulate the proliferation of inherent NSCs, and most proliferated NSCs may differentiate into neurons and represent neural plasticity.

Adult Stem Cells ; cytology ; metabolism ; Animals ; Bromodeoxyuridine ; metabolism ; Cell Nucleus ; pathology ; Cerebral Infarction ; metabolism ; pathology ; Dentate Gyrus ; cytology ; metabolism ; Glial Fibrillary Acidic Protein ; metabolism ; Hippocampus ; cytology ; metabolism ; Male ; Nerve Tissue Proteins ; metabolism ; Neural Cell Adhesion Molecule L1 ; metabolism ; Neurogenesis ; physiology ; Neurons ; cytology ; metabolism ; Rats ; Rats, Wistar ; Sialic Acids ; metabolism