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Sample records for 9-o-acetyl gd3 gangliosides

  1. Mice lacking GD3 synthase display morphological abnormalities in the sciatic nerve and neuronal disturbances during peripheral nerve regeneration.

    PubMed

    Ribeiro-Resende, Victor Túlio; Araújo Gomes, Tiago; de Lima, Silmara; Nascimento-Lima, Maiara; Bargas-Rega, Michele; Santiago, Marcelo Felipe; Reis, Ricardo Augusto de Melo; de Mello, Fernando Garcia

    2014-01-01

    The ganglioside 9-O-acetyl GD3 is overexpressed in peripheral nerves after lesioning, and its expression is correlated with axonal degeneration and regeneration in adult rodents. However, the biological roles of this ganglioside during the regenerative process are unclear. We used mice lacking GD3 synthase (Siat3a KO), an enzyme that converts GM3 to GD3, which can be further converted to 9-O-acetyl GD3. Morphological analyses of longitudinal and transverse sections of the sciatic nerve revealed significant differences in the transverse area and nerve thickness. The number of axons and the levels of myelin basic protein were significantly reduced in adult KO mice compared to wild-type (WT) mice. The G-ratio was increased in KO mice compared to WT mice based on quantification of thin transverse sections stained with toluidine blue. We found that neurite outgrowth was significantly reduced in the absence of GD3. However, addition of exogenous GD3 led to neurite growth after 3 days, similar to that in WT mice. To evaluate fiber regeneration after nerve lesioning, we compared the regenerated distance from the lesion site and found that this distance was one-fourth the length in KO mice compared to WT mice. KO mice in which GD3 was administered showed markedly improved regeneration compared to the control KO mice. In summary, we suggest that 9-O-acetyl GD3 plays biological roles in neuron-glia interactions, facilitating axonal growth and myelination induced by Schwann cells. Moreover, exogenous GD3 can be converted to 9-O-acetyl GD3 in mice lacking GD3 synthase, improving regeneration.

  2. Mice Lacking GD3 Synthase Display Morphological Abnormalities in the Sciatic Nerve and Neuronal Disturbances during Peripheral Nerve Regeneration

    PubMed Central

    Ribeiro-Resende, Victor Túlio; Gomes, Tiago Araújo; de Lima, Silmara; Nascimento-Lima, Maiara; Bargas-Rega, Michele; Santiago, Marcelo Felipe; Reis, Ricardo Augusto de Melo; de Mello, Fernando Garcia

    2014-01-01

    The ganglioside 9-O-acetyl GD3 is overexpressed in peripheral nerves after lesioning, and its expression is correlated with axonal degeneration and regeneration in adult rodents. However, the biological roles of this ganglioside during the regenerative process are unclear. We used mice lacking GD3 synthase (Siat3a KO), an enzyme that converts GM3 to GD3, which can be further converted to 9-O-acetyl GD3. Morphological analyses of longitudinal and transverse sections of the sciatic nerve revealed significant differences in the transverse area and nerve thickness. The number of axons and the levels of myelin basic protein were significantly reduced in adult KO mice compared to wild-type (WT) mice. The G-ratio was increased in KO mice compared to WT mice based on quantification of thin transverse sections stained with toluidine blue. We found that neurite outgrowth was significantly reduced in the absence of GD3. However, addition of exogenous GD3 led to neurite growth after 3 days, similar to that in WT mice. To evaluate fiber regeneration after nerve lesioning, we compared the regenerated distance from the lesion site and found that this distance was one-fourth the length in KO mice compared to WT mice. KO mice in which GD3 was administered showed markedly improved regeneration compared to the control KO mice. In summary, we suggest that 9-O-acetyl GD3 plays biological roles in neuron-glia interactions, facilitating axonal growth and myelination induced by Schwann cells. Moreover, exogenous GD3 can be converted to 9-O-acetyl GD3 in mice lacking GD3 synthase, improving regeneration. PMID:25330147

  3. Progenitor/Stem Cell Markers in Brain Adjacent to Glioblastoma: GD3 Ganglioside and NG2 Proteoglycan Expression.

    PubMed

    Lama, Gina; Mangiola, Annunziato; Proietti, Gabriella; Colabianchi, Anna; Angelucci, Cristiana; D' Alessio, Alessio; De Bonis, Pasquale; Geloso, Maria Concetta; Lauriola, Libero; Binda, Elena; Biamonte, Filippo; Giuffrida, Maria Grazia; Vescovi, Angelo; Sica, Gigliola

    2016-02-01

    Characterization of tissue surrounding glioblastoma (GBM) is a focus for translational research because tumor recurrence invariably occurs in this area. We investigated the expression of the progenitor/stem cell markers GD3 ganglioside and NG2 proteoglycan in GBM, peritumor tissue (brain adjacent to tumor, BAT) and cancer stem-like cells (CSCs) isolated from GBM (GCSCs) and BAT (PCSCs). GD3 and NG2 immunohistochemistry was performed in paired GBM and BAT specimens from 40 patients. Double-immunofluorescence was carried out to characterize NG2-positive cells of vessel walls. GD3 and NG2 expression was investigated in GCSCs and PCSCs whose tumorigenicity was also evaluated in Scid/bg mice. GD3 and NG2 expression was higher in tumor tissue than in BAT. NG2 decreased as the distance from tumor margin increased, regardless of the tumor cell presence, whereas GD3 correlated with neoplastic infiltration. In BAT, NG2 was coexpressed with a-smooth muscle actin (a-SMA) in pericytes and with nestin in the endothelium. Higher levels of NG2 mRNA and protein were found in GCSCs while GD3 synthase was expressed at similar levels in the 2 CSC populations. PCSCs had lower tumorigenicity than GCSCs. These data suggest the possible involvement of GD3 and NG2 in pre/pro-tumorigenic events occurring in the complex microenvironment of the tissue surrounding GBM.

  4. Preparation of CD4+ T Cells for Analysis of GD3 and GD2 Ganglioside Membrane Expression by Microscopy.

    PubMed

    Villanueva-Cabello, Tania M; Martinez-Duncker, Iván

    2016-11-08

    The methods described herein for activation of naïve CD4(+) T cells in suspension and their adherence in coverslips for confocal microscopy analysis allow the spatial localization and visualization of gangliosides involved in CD4(+) T cell activation, that complement expression profiling experiments such as flow cytometry, western blotting or real-time PCR. The quantification of ganglioside expression through flow cytometry and their cellular localization through microscopy can be obtained by the use of anti-ganglioside antibodies with high affinity and specificity. Nonetheless, an adequate handling of cells in suspension involves the treatment of culture plates to promote the necessary adherence required for fluorescence or confocal microscopy acquisition. In this work, we describe a protocol for determining GD3 and GD2 ganglioside expression and colocalization with the TCR during naïve CD4(+) T cell activation. Also, real-time PCR experiments using <40,000 cells are described for the determination of the GD3 and GM2/GD2 synthase genes, demonstrating that gene analysis experiments can be performed with a low number of cells and without the need of additional low input RNA kits.

  5. Segregation of gangliosides GM1 and GD3 on cell membranes, isolated membrane rafts, and defined supported lipid monolayers.

    PubMed

    Vyas, K A; Patel, H V; Vyas, A A; Schnaar, R L

    2001-02-01

    Lateral assemblies of sphingolipids, glycosphingolipids and cholesterol, termed rafts, are postulated to be present in biological membranes and to function in important cellular phenomena. We probed whether rafts are heterogeneous by determining the relative distribution of two gangliosides, GM1 and GD3, in artificial supported monolayers, in intact rat primary cerebellar granule neurones, and in membrane rafts isolated from rat cerebellum. Fluorescence resonance energy transfer (FRET) using fluorophore-labelled cholera toxin B subunit (which binds GM1) and mAb R24 (which binds GD3) revealed that GM1 spontaneously self-associates but does not co-cluster with GD3 in supported monolayers and on intact neurones. Cholera toxin and immunocytochemical labelling of isolated membrane rafts from rat cerebellum further demonstrated that GM1 does not co-localise with GD3. Furthermore, whereas the membrane raft resident proteins Lyn and caveolin both co-localise with GD3 in isolated membrane rafts, GM1 appears in separate and distinct aggregates. These data support prior reports that membrane rafts are heterogeneous, although the mechanisms for establishing and maintaining such heterogeneity remain to be determined.

  6. UVB-irradiated keratinocytes induce melanoma-associated ganglioside GD3 synthase gene in melanocytes via secretion of tumor necrosis factor α and interleukin 6.

    PubMed

    Miyata, Maiko; Ichihara, Masatoshi; Tajima, Orie; Sobue, Sayaka; Kambe, Mariko; Sugiura, Kazumitsu; Furukawa, Koichi; Furukawa, Keiko

    2014-03-07

    Although expression of gangliosides and their synthetic enzyme genes in malignant melanomas has been well studied, that in normal melanocytes has been scarcely analyzed. In particular, changes in expression levels of glycosyltransferase genes responsible for ganglioside synthesis during evolution of melanomas from melanocytes are very important to understand roles of gangliosides in melanomas. Here, expression of glycosyltransferase genes related to the ganglioside synthesis was analyzed using RNAs from cultured melanocytes and melanoma cell lines. Quantitative RT-PCR revealed that melanomas expressed high levels of mRNA of GD3 synthase and GM2/GD2 synthase genes and low levels of GM1/GD1b synthase genes compared with melanocytes. As a representative exogenous stimulation, effects of ultraviolet B (UVB) on the expression levels of 3 major ganglioside synthase genes in melanocytes were analyzed. Although direct UVB irradiation of melanocytes caused no marked changes, culture supernatants of UVB-irradiated keratinocytes (HaCaT cells) induced definite up-regulation of GD3 synthase and GM2/GD2 synthase genes. Detailed examination of the supernatants revealed that inflammatory cytokines such as TNFα and IL-6 enhanced GD3 synthase gene expression. These results suggest that inflammatory cytokines secreted from UVB-irradiated keratinocytes induced melanoma-associated ganglioside synthase genes, proposing roles of skin microenvironment in the promotion of melanoma-like ganglioside profiles in melanocytes.

  7. Ganglioside GD3 Enhances Invasiveness of Gliomas by Forming a Complex with Platelet-derived Growth Factor Receptor α and Yes Kinase.

    PubMed

    Ohkawa, Yuki; Momota, Hiroyuki; Kato, Akira; Hashimoto, Noboru; Tsuda, Yusuke; Kotani, Norihiro; Honke, Koichi; Suzumura, Akio; Furukawa, Keiko; Ohmi, Yuhsuke; Natsume, Atsushi; Wakabayashi, Toshihiko; Furukawa, Koichi

    2015-06-26

    There have been a few studies on the ganglioside expression in human glioma tissues. However, the role of these gangliosides such as GD3 and GD2 has not been well understood. In this study we employed a genetically engineered mouse model of glioma to clarify the functions of GD3 in gliomas. Forced expression of platelet-derived growth factor B in cultured astrocytes derived from p53-deficient mice resulted in the expression of GD3 and GD2. GD3-positive astrocytes exhibited increased cell growth and invasion activities along with elevated phosphorylation of Akt and Yes kinase. By enzyme-mediated activation of radical sources reaction and mass spectrometry, we identified PDGF receptor α (PDGFRα) as a GD3-associated molecule. GD3-positive astrocytes showed a significant amount of PDGFRα in glycolipid-enriched microdomains/rafts compared with GD3-negative cells. Src kinase family Yes was co-precipitated with PDGFRα, and its pivotal role in the increased cell invasion of GD3-positive astrocytes was demonstrated by silencing with anti-Yes siRNA. Direct association between PDGFRα and GD3 was also shown, suggesting that GD3 forms ternary complex with PDGFRα and Yes. The fact that GD3, PDGFRα, and activated Yes were colocalized in lamellipodia and the edge of tumors in cultured cells and glioma tissues, respectively, suggests that GD3 induced by platelet-derived growth factor B enhances PDGF signals in glycolipid-enriched microdomain/rafts, leading to the promotion of malignant phenotypes such as cell proliferation and invasion in gliomas.

  8. UVB-irradiated keratinocytes induce melanoma-associated ganglioside GD3 synthase gene in melanocytes via secretion of tumor necrosis factor α and interleukin 6

    SciTech Connect

    Miyata, Maiko; Ichihara, Masatoshi; Tajima, Orie; Sobue, Sayaka; Kambe, Mariko; Sugiura, Kazumitsu; Furukawa, Koichi; Furukawa, Keiko

    2014-03-07

    Highlights: • Melanocytes showed low ST8SIA1 and high B3GALT4 levels in contrast with melanomas. • Direct UVB irradiation of melanocytes did not induce ganglioside synthase genes. • Culture supernatants of UVB-irradiated keratinocytes induced ST8SIA1 in melanocytes. • TNFα and IL-6 secreted from keratinocytes enhanced ST8SIA1 expression in melanocytes. • Inflammatory cytokines induced melanoma-related ST8SIA1 in melanocytes. - Abstract: Although expression of gangliosides and their synthetic enzyme genes in malignant melanomas has been well studied, that in normal melanocytes has been scarcely analyzed. In particular, changes in expression levels of glycosyltransferase genes responsible for ganglioside synthesis during evolution of melanomas from melanocytes are very important to understand roles of gangliosides in melanomas. Here, expression of glycosyltransferase genes related to the ganglioside synthesis was analyzed using RNAs from cultured melanocytes and melanoma cell lines. Quantitative RT-PCR revealed that melanomas expressed high levels of mRNA of GD3 synthase and GM2/GD2 synthase genes and low levels of GM1/GD1b synthase genes compared with melanocytes. As a representative exogenous stimulation, effects of ultraviolet B (UVB) on the expression levels of 3 major ganglioside synthase genes in melanocytes were analyzed. Although direct UVB irradiation of melanocytes caused no marked changes, culture supernatants of UVB-irradiated keratinocytes (HaCaT cells) induced definite up-regulation of GD3 synthase and GM2/GD2 synthase genes. Detailed examination of the supernatants revealed that inflammatory cytokines such as TNFα and IL-6 enhanced GD3 synthase gene expression. These results suggest that inflammatory cytokines secreted from UVB-irradiated keratinocytes induced melanoma-associated ganglioside synthase genes, proposing roles of skin microenvironment in the promotion of melanoma-like ganglioside profiles in melanocytes.

  9. 9-O-Acetylation of sialic acids is catalysed by CASD1 via a covalent acetyl-enzyme intermediate

    PubMed Central

    Baumann, Anna-Maria T.; Bakkers, Mark J. G.; Buettner, Falk F. R.; Hartmann, Maike; Grove, Melanie; Langereis, Martijn A.; de Groot, Raoul J.; Mühlenhoff, Martina

    2015-01-01

    Sialic acids, terminal sugars of glycoproteins and glycolipids, play important roles in development, cellular recognition processes and host–pathogen interactions. A common modification of sialic acids is 9-O-acetylation, which has been implicated in sialoglycan recognition, ganglioside biology, and the survival and drug resistance of acute lymphoblastic leukaemia cells. Despite many functional implications, the molecular basis of 9-O-acetylation has remained elusive thus far. Following cellular approaches, including selective gene knockout by CRISPR/Cas genome editing, we here show that CASD1—a previously identified human candidate gene—is essential for sialic acid 9-O-acetylation. In vitro assays with the purified N-terminal luminal domain of CASD1 demonstrate transfer of acetyl groups from acetyl-coenzyme A to CMP-activated sialic acid and formation of a covalent acetyl-enzyme intermediate. Our study provides direct evidence that CASD1 is a sialate O-acetyltransferase and serves as key enzyme in the biosynthesis of 9-O-acetylated sialoglycans. PMID:26169044

  10. Accumulation of unusual gangliosides G(Q3) and G(P3) in breast cancer cells expressing the G(D3) synthase.

    PubMed

    Steenackers, Agata; Vanbeselaere, Jorick; Cazet, Aurélie; Bobowski, Marie; Rombouts, Yoann; Colomb, Florent; Le Bourhis, Xuefen; Guérardel, Yann; Delannoy, Philippe

    2012-08-10

    Glycosphingolipids from the ganglio-series are usually classified in four series according to the presence of 0 to 3 sialic acid residues linked to lactosylceramide. The transfer of sialic acid is catalyzed in the Golgi apparatus by specific sialyltransferases that show high specificity toward glycolipid substrates. ST8Sia I (EC 2.4.99.8, SAT-II, SIAT 8a) is the key enzyme controlling the biosynthesis of b- and c-series gangliosides. ST8Sia I is expressed at early developmental stages whereas in adult human tissues, ST8Sia I transcripts are essentially detected in brain. ST8Sia I together with b- and c-series gangliosides are also over-expressed in neuroectoderm-derived malignant tumors such as melanoma, glioblastoma, neuroblastoma and in estrogen receptor (ER) negative breast cancer, where they play a role in cell proliferation, migration, adhesion and angiogenesis. We have stably expressed ST8Sia I in MCF-7 breast cancer cells and analyzed the glycosphingolipid composition of wild type (WT) and GD3S+ clones. As shown by mass spectrometry, MCF-7 expressed a complex pattern of neutral and sialylated glycosphingolipids from globo- and ganglio-series. WT MCF-7 cells exhibited classical monosialylated gangliosides including G(M3), G(M2), and G(M1a). In parallel, the expression of ST8Sia I in MCF-7 GD3S+ clones resulted in a dramatic change in ganglioside composition, with the expression of b- and c-series gangliosides as well as unusual tetra- and pentasialylated lactosylceramide derivatives G(Q3) (II(3)Neu5Ac(4)-Gg(2)Cer) and G(P3) (II(3)Neu5Ac(5)-Gg(2)Cer). This indicates that ST8Sia I is able to act as an oligosialyltransferase in a cellular context.

  11. Biosynthesis and turnover of O-acetyl and N-acetyl groups in the gangliosides of human melanoma cells

    SciTech Connect

    Manzi, A.E.; Sjoberg, E.R.; Diaz, S.; Varki, A.

    1990-08-05

    We and others previously described the melanoma-associated oncofetal glycosphingolipid antigen 9-O-acetyl-GD3, a disialoganglioside O-acetylated at the 9-position of the outer sialic acid residue. We have now developed methods to examine the biosynthesis and turnover of disialogangliosides in cultured melanoma cells and in Golgi-enriched vesicles from these cells. O-Acetylation was selectively expressed on di- and trisialogangliosides, but not on monosialogangliosides, nor on glycoprotein-bound sialic acids. Double-labeling of cells with (3H)acetate and (14C)glucosamine introduced easily detectable labels into each of the components of the ganglioside molecules. Pulse-chase studies of such doubly labeled molecules indicated that the O-acetyl groups turn over faster than the parent molecule. When Golgi-enriched vesicles from these cells were incubated with (acetyl-3H)acetyl-coenzyme A, the major labeled products were disialogangliosides. (Acetyl-3H)O-acetyl groups were found at both the 7- and the 9-positions, indicating that both 7-O-acetyl GD3 and 9-O-acetyl GD3 were synthesized by the action of O-acetyltransferase(s) on endogenous GD3. Analysis of the metabolically labeled molecules confirmed the existence of both 7- and 9-O-acetylated GD3 in the intact cells. Surprisingly, the major 3H-labeled product of the in vitro labeling reaction was not O-acetyl-GD3, but GD3, with the label exclusively in the sialic acid residues. Fragmentation of the labeled sialic acids by enzymatic and chemical methods showed that the 3H-label was exclusively in (3H)N-acetyl groups. Analyses of the double-labeled sialic acids from intact cells also showed that the 3H-label from (3H)acetate was exclusively in the form of (3H)N-acetyl groups, whereas the 14C-label was at the 4-position.

  12. Functional activation of Src family kinase yes protein is essential for the enhanced malignant properties of human melanoma cells expressing ganglioside GD3.

    PubMed

    Hamamura, Kazunori; Tsuji, Momoko; Hotta, Hiroshi; Ohkawa, Yuki; Takahashi, Masataka; Shibuya, Hidenobu; Nakashima, Hideyuki; Yamauchi, Yoshio; Hashimoto, Noboru; Hattori, Hisashi; Ueda, Minoru; Furukawa, Keiko; Furukawa, Koichi

    2011-05-27

    The possible roles of Src family kinases in the enhanced malignant properties of melanomas related to GD3 expression were analyzed. Among Src family kinases only Yes, not Fyn or Src, was functionally involved in the increased cell proliferation and invasion of GD3-expressing transfectant cells (GD3+). Yes was located upstream of p130Cas and paxillin and at an equivalent level to focal adhesion kinase. Yes underwent autophosphorylation even before serum treatment and showed stronger kinase activity in GD3+ cells than in GD3- cells following serum treatment. Coimmunoprecipitation experiments revealed that Yes bound to focal adhesion kinase or p130Cas more strongly in GD3+ cells than in GD3- cells. As a possible mechanism for the enhancing effects of GD3 on cellular phenotypes, it was shown that majority of Yes was localized in glycolipid-enriched microdomain/rafts in GD3+ cells even before serum treatment, whereas it was scarcely detected in glycolipid-enriched microdomain/rafts in GD3- cells. An in vitro kinase assay of Yes revealed that coexistence of GD3 with Yes in membranous environments enhances the kinase activity of GD3- cell-derived Yes toward enolase, p125, and Yes itself. Knockdown of GD3 synthase resulted in the alleviation of tumor phenotypes and reduced activation levels of Yes. Taken together, these results suggest a role of GD3 in the regulation of Src family kinases.

  13. Ganglioside biosynthesis in developing brains and apoptotic cancer cells: X. regulation of glyco-genes involved in GD3 and Sialyl-Lex/a syntheses.

    PubMed

    Basu, Subhash; Ma, Rui; Moskal, Joseph R; Basu, Manju

    2012-06-01

    Gangliosides, the acidic glycosphingolipids (GSLs) containing N-acetylgalactosamine and sialic acid are ubiquitous in the central nervous system. At least six DSL-glycosyltransferase activities (GLTs Gangliosides, the acidic glycosphingolipids (GSLs) containing N-acetylgalactosamine and sialic acid (or NAc-Neuraminic acid) are ubiquitous in the central nervous system. At least six GSL-glycosyltransferase activities (GLTs) of Basu-Roseman pathway catalyzing the biosynthesis of these gangliosides have been characterized in developing chicken brains. Most of these glyco-genes are expressed in the early stages (7-17 days) of brain development and lowered in the adult stage, but the cause of reduction of enzymatic activities of these GLTs in the adult stages is not known. In order to study glyco-gene regulation we used four clonal metastatic cancer cells of colon and breast cancer tissue origin (Colo-205, SKBR-3, MDA-468, and MCF-3). The glyco-genes for synthesis of SA-LeX and SA-LeA (which contain N-acetylglucosamine, sialic acid and fucose) in these cells were modulated differently at different phases (between 2 and 48 h) of apoptotic inductions. L-PPMP, D-PDMP (inhibitor of glucosylceramide biosynthesis), Betulinic Acid (a triterpinoid isolated from bark of certain trees and used for cancer treatment in China), Tamoxifen a drug in use in the west for treatment of early stages of the disease in breast cancer patients), and cis-platin (an inhibitor of DNA biosynthesis used for testicular cancer patients) were used for induction of apoptosis in the above-mentioned cell lines. Within 2-6 h, transcriptional modulation of a number of glyco-genes was observed by DNA-micro-array (containing over 300 glyco genes attached to the glass cover slips) studies. Under long incubation time (24-48 h) almost all of the glyco-genes were downregulated. The cause of these glyco-gene regulations during apoptotic induction in metastatic carcinoma cells is unknown and needs future

  14. The S protein of bovine coronavirus is a hemagglutinin recognizing 9-O-acetylated sialic acid as a receptor determinant.

    PubMed Central

    Schultze, B; Gross, H J; Brossmer, R; Herrler, G

    1991-01-01

    The S protein of bovine coronavirus (BCV) has been isolated from the viral membrane and purified by gradient centrifugation. Purified S protein was identified as a viral hemagglutinin. Inactivation of the cellular receptors by sialate 9-O-acetylesterase and generation of receptors by sialylation of erythrocytes with N-acetyl-9-O-acetylneuraminic acid (Neu5,9Ac2) indicate that S protein recognizes 9-O-acetylated sialic acid as a receptor determinant as has been shown previously for intact virions. The second glycoprotein of BCV, HE, which has been thought previously to be responsible for the hemagglutinating activity of BCV, is a less efficient hemagglutinin; it agglutinates mouse and rat erythrocytes, but in contrast to S protein, it is unable to agglutinate chicken erythrocytes, which contain a lower level of Neu5,9Ac2 on their surface. S protein is proposed to be responsible for the primary attachment of virus to cell surface. S protein is proposed to be responsible for the primary attachement of virus to cell surface receptors. The potential of S protein as a probe for the detection of Neu5,9Ac2-containing glycoconjugates is demonstrated. Images PMID:1920630

  15. [Gangliosides in the serum in lung carcinoma].

    PubMed

    Fumić, K; Vladović-Relja, T; Karada, J; Kracun, I; Stavljenić, A; Kubat, M; Cosović, C; Oberman, B

    1990-01-01

    In this study, tumor and serum gangliosides were analyzed in patients bearing lung planocellular carcinoma (LPC) before and after operative therapy. Tumor tissue, pathohistologically characterized as carcinoma planocellulare corneum (Ca. epidermoide, type 8070/3, WHO, Geneva, 1981), showed an elevated concentration of gangliosides in comparison to normal tung tissue. The composition of gangliosides in LPC tissue varied from one tumor sample to another, however, two general features were observed. First, LPC contained an increased amount of GM3 and a decreased amount of GD3 gangliosides. Second, an elevated proportion of gangliosides migrating as polysialogangliosides (x3, x5, x6) characterized the majority of LPC tissues. On the other hand, serum of patients with LPC contained an elevated amount of gangliosides (15.8 +/- 0.3 mumols/L) in comparison to control serum (6.1 +/- 0.8 mumols/L) (P less than 0.01). However, analyzing the composition of serum gangliosides by thin-layer chromatography, all serum gangliosides were more or less elevated. By day 21 after the surgical removal of LPC, serum gangliosides dropped by approximately 50% approaching the normal values. It seems that elevated serum gangliosides in LPC patients were secreted from carcinoma cells, because they normalized after surgical removal of LPC. Thus, serum gangliosides might be a useful biochemical tool for diagnosis and therapy monitoring of this carcinoma.

  16. Regulation by GD3 of the proinflammatory response of microglia mediated by interleukin-15.

    PubMed

    Gómez-Nicola, Diego; Doncel-Pérez, Ernesto; Nieto-Sampedro, Manuel

    2006-04-01

    The interleukin (IL)-15-dependent immune responses of murine microglia were strongly affected by low concentrations of the ganglioside GD3. The ganglioside binding to IL-15 inhibited the proinflammatory effects of the cytokine, reducing IL-15-dependent T-cell proliferation as well as mRNA expression for IL-15Ralpha, p65, and NFATc2 in the N13 murine microglial cell line. Treatment of primary murine microglial cultures with GD3 abolished IL-15 production, without affecting cellular viability, but decreased the production of nitric oxide, a direct sensor of inflammation and nuclear factor-kappaB activity. We conclude that low doses of GD3 could inhibit specific proinflammatory mechanisms and modulate the inflammatory environment, leading to a less reactive scene. Microglial cells are one of the main actors in the inflammatory events that follow CNS trauma or an autoimmune disease episode, modulating the internal production of cytokines, growth factors, and other homeostatic molecules that may determine the evolution and outcome of tissue damage. Proinflammatory cytokines have a relevant role in the initial events, and modulation of their activity by gangliosides could cut down their harmful effects and interfere with invasion of the CNS by peripheral immune cells. The antiinflammatory properties of GD3 could be significant in the treatment of pain subsequent to CNS damage.

  17. Identification of N-acetylneuraminic acid and its 9-O-acetylated derivative on the cell surface of Cryptococcus neoformans: influence on fungal phagocytosis.

    PubMed Central

    Rodrigues, M L; Rozental, S; Couceiro, J N; Angluster, J; Alviano, C S; Travassos, L R

    1997-01-01

    Sialic acids from sialoglycoconjugates present at the cell surface of Cryptococcus neoformans yeast forms were analyzed by high-performance thin-layer chromatography, binding of influenza A and C virus strains, enzymatic treatment, and flow cytofluorimetry with fluorescein isothiocyanate-labeled lectins. C. neoformans yeast forms grown in a chemically defined medium contain N-acetylneuraminic acid and its 9-O-acetylated derivative. A density of 3 x 10(6) residues of sialic acid per cell was found in C. neoformans. Sialic acids in cryptococcal cells are glycosidically linked to galactopyranosyl units as inferred from the increased reactivity of neuraminidase-treated yeasts with peanut agglutinin. N-Acetylneuraminic acids are alpha-2,6 and alpha-2,3 linked, as indicated by using virus strains M1/5 and M1/5 HS8, respectively, as agglutination probes. The alpha-2,6 linkage markedly predominated. These findings were essentially confirmed by the interaction of cryptococcal cells with the lectins Sambucus nigra agglutinin and Maackia amurensis agglutinin. We also investigated whether the sialyl residues present in C. neoformans are involved in the fungal interaction with a cationic solid-phase substrate and with mouse resident macrophages. Adhesion of yeast cells to poly-L-lysine was mediated, in part, by sialic acid residues, since the number of adherent cells was markedly reduced after treatment with bacterial neuraminidase. The enzymatic removal of sialic acids also made C. neoformans yeast cells more susceptible to endocytosis by macrophages. The results show that sialic acids are components of the cryptococcal cell surface that contribute to its negative charge and protect yeast forms against phagocytosis. PMID:9393779

  18. O-acetylated sialic acids in gangliosides from pig spleen lymphocytes.

    PubMed

    Hueso, P; Cabezas, J A; Reglero, A

    1988-01-01

    The sialic acid content of gangliosides from pig spleen lymphocytes was studied by thin-layer chromatography. N-glycolylneuraminic acid and N-acetylneuraminic acid were detected for the first time in this material as the major sialic acids. In addition, two other sialic acids, tentatively designated O-acetylated sialic acids, according to their RF values on cellulose plates, were also found. We have detected several gangliosides showing a retarded migration pattern in two dimensional thin-layer chromatography with an intermediate ammonia treatment. One of these gangliosides could be an O-acetylated derivative of the disialoganglioside GD3, since after de-O-acetyation it co-migrates with GD3. Another ganglioside co-migrated with GM2 before the alkaline treatment; however, after the treatment it was also retarded and co-migrates with GD3.

  19. Ganglioside Biochemistry

    PubMed Central

    Kolter, Thomas

    2012-01-01

    Gangliosides are sialic acid-containing glycosphingolipids. They occur especially on the cellular surfaces of neuronal cells, where they form a complex pattern, but are also found in many other cell types. The paper provides a general overview on their structures, occurrence, and metabolism. Key functional, biochemical, and pathobiochemical aspects are summarized. PMID:25969757

  20. High-affinity anti-ganglioside IgG antibodies raised in complex ganglioside knockout mice: reexamination of GD1a immunolocalization.

    PubMed

    Lunn, M P; Johnson, L A; Fromholt, S E; Itonori, S; Huang, J; Vyas, A A; Hildreth, J E; Griffin, J W; Schnaar, R L; Sheikh, K A

    2000-07-01

    Gangliosides, sialic acid-bearing glycosphingolipids, are highly enriched in the vertebrate nervous system. Anti-ganglioside antibodies are associated with various human neuropathies, although the pathogenicity of these antibodies remains unproven. Testing the pathogenic role of anti-ganglioside antibodies will be facilitated by developing high-affinity IgG-class complement-fixing monoclonal anti-bodies against major brain gangliosides, a goal that has been difficult to achieve. In this study, mice lacking complex gangliosides were used as immune-naive hosts to raise anti-ganglioside antibodies. Wild-type mice and knockout mice with a disrupted gene for GM2/GD2 synthase (UDP-N-acetyl-D-galactosamine : GM3/GD3 N-acetyl-D-glactosaminyltransferase) were immunized with GD1a conjugated to keyhole limpet hemocyanin. The knockout mice produced a vigorous anti-GD1a IgG response, whereas wildtype littermates failed to do so. Fusion of spleen cells from an immunized knockout mouse with myeloma cells yielded numerous IgG anti-GD1a antibody-producing colonies. Ganglioside binding studies revealed two specificity classes; one colony representing each class was cloned and characterized. High-affinity monoclonal antibody was produced by each hybridoma : an IgG1 that bound nearly exclusively to GD1a and an IgG2b that bound GD1a, GT1b, and GT1aalpha. Both antibodies readily readily detected gangliosides via ELISA, TLC immune overlay, immunohistochemistry, and immunocytochemistry. In contrast to prior reports using anti-GD1a and anti-GT1b IgM class monoclonal antibodies, the new antibodies bound avidly to granule neurons in brain tissue sections and cell cultures. Mice lacking complex gangliosides are improved hosts for raising high-affinity, high-titer anti-ganglioside IgG antibodies for probing for the distribution and physiology of gangliosides and the pathophysiology of anti-ganglioside antibodies.

  1. Immunoglobulin G-class mouse monoclonal antibodies to major brain gangliosides.

    PubMed

    Schnaar, Ronald L; Fromholt, Susan E; Gong, Yanping; Vyas, Alka A; Laroy, Wouter; Wayman, Dawn M; Heffer-Lauc, Marija; Ito, Hiromi; Ishida, Hideharu; Kiso, Makoto; Griffin, John W; Shiekh, Kazim A

    2002-03-15

    Mice genetically engineered to lack complex gangliosides are improved hosts for raising antibodies against those gangliosides. We report the generation and characterization of nine immunoglobulin G (IgG)-class monoclonal antibodies (mAbs) raised against the four major brain gangliosides in mammals. These include (designated as ganglioside specificity-IgG subclass) two anti-GM1 mAbs (GM1-1, GM1-2b), three anti-GD1a mAbs (GD1a-1, GD1a-2a, GD1a-2b), one anti-GD1b mAb (GD1b-1), and three anti-GT1b mAbs (GT1b-1, GT1b-2a, GT1b-2b). Each mAb demonstrated high specificity, with little or no cross-reactivity with other major brain gangliosides. Enzyme-linked immunosorbent assay (ELISA) screening against 14 closely related synthetic and purified gangliosides confirmed the high specificity, with no significant cross-reactivity except that of the anti-GD1a mAbs for the closely related minor ganglioside GT1a alpha. All of the mAbs were useful for ELISA, TLC immunooverlay, and immunocytochemistry. Neural cells from wild-type rats and mice were immunostained to differing levels with the anti-ganglioside antibodies, whereas neural cells from mice engineered to lack complex gangliosides (lacking the ganglioside-specific biosynthetic enzyme UDP-GalNAc:GM3/GD3 N-acetylgalactosaminyltransferase) remained unstained, demonstrating that most of the mAbs react only with gangliosides and not with related structures on glycoproteins. These mAbs may provide useful tools for delineation of the expression and function of the major brain gangliosides and for probing the pathology of anti-ganglioside autoimmune diseases.

  2. Disialyl GD2 ganglioside suppresses ICAM-1-mediated invasiveness in human breast cancer MDA-MB231 cells

    PubMed Central

    Kwon, Kyung-Min; Chung, Tae-Wook; Kwak, Choong-Hwan; Choi, Hee-Jung; Kim, Kyung-Woon; Ha, Sun-Hyung; Cho, Seung-Hak; Lee, Young-Choon; Ha, Ki-Tae; Lee, Moon-Jo; Kim, Cheorl-Ho

    2017-01-01

    The disialoganglioside GD3 has been considered to be involved in tumor progression or suppression in various tumor cells. However, the significance of the biological functions of GD3 in breast cancer cells is still controversial. This prompted us to study the possible relationship(s) between GD3 expression and the metastatic potential of a breast cancer MDA-MB231 cells as an estrogen receptor negative (ER-) type. The human GD3 synthase cDNA was transfected into MDA-MB231 cells, and G-418 bulk selection was used to select cells stably overexpressing the GD3 synthase. In vitro invasion potentials of the GD3 synthase over-expressing cells (pc3-GD3s) were significantly suppressed when compared with control cells. Expression of intercellular adhesion molecule-1 (ICAM-1; CD54) was down-regulated in the pc3-GD3s cells and the decrease in ICAM-I expression is directly related to the decrease in invasiveness of the pc3-GD3s cells. Another type of ER negative SK-BR3 cells exhibited the similar level of ICAM-1 expression as MDA-MB231 cells, while the ER positive MCF-7 cells (ER+) showed the increased expression level of ICAM-1. Then, we investigated signaling pathways known to control ICAM-1 expression. No difference was observed in the phosphorylation of ERK and p38 between the pc3-GD3s and control cells (pc3), but the activation of AKT was inhibited in pc3-GD3s, and not in the control (pc3). In addition, the composition of total gangliosides was changed between control (pc3) and pc3-GD3s cells, as confirmed by HPTLC. The pc3-GD3s cells had an accumulation of the GD2 instead of the GD3. RT-PCR results showed that not only GD3 synthase, but also GM2/GD2 synthase (β4-GalNc T) expression was increased in pc3-GD3s cells. Overexpression of GD3 synthase suppresses the invasive potential of human breast cancer MDA-MB-231 cells through down-regulation of ICAM-1 and the crucial pathway to allow the apoptotic effect has been attributed to accumulation of the GD2 ganglioside. ER has

  3. Synthesis of ganglioside epitopes for oligosaccharide specific immunoadsorption therapy of Guillian-Barré syndrome.

    PubMed

    Andersen, Søren M; Ling, Chang-Chun; Zhang, Ping; Townson, Kate; Willison, Hugh J; Bundle, David R

    2004-04-21

    Guillain-Barré syndrome is a postinfectious, autoimmune neuropathy resulting in neuromuscular paralysis. Auto-antibodies, often induced by bacterial infection, bind to human gangliosides possessing monosialoside and diasialoside epitopes and impair the function of nerve junctions, where these ganglioside structures are highly enriched. Truncated gangliosides representive of GD3, GQ1b and GM2 epitopes have been synthesized as methyl glycosides and as a glycosides of an eleven carbon tether. The synthetic oligosaccharide ligands are structural mimics of these highly complex ganglioside epitopes and via their ability to neutralize or remove auto-antibodies have the potential for therapy, either as soluble blocking ligands administered systemically, or as immuno-affinity ligands for use as extracorporeal immunoadsorbents.

  4. A new sialic acid analogue, 9-O-acetyl-deaminated neuraminic acid, and alpha -2,8-linked O-acetylated poly(N-glycolylneuraminyl) chains in a novel polysialoglycoprotein from salmon eggs.

    PubMed

    Iwasaki, M; Inoue, S; Troy, F A

    1990-02-15

    A new polysialoglycoprotein, designated PSGP(On), was isolated from the unfertilized eggs of the kokanee salmon, Oncorhynchus nerka adonis. 400-MHz 1H NMR analyses showed the O. nerka adonis PSGP contained alpha -2,8-linked oligo- and polysialic acid (polySia) chains that were made up of 4-O-Ac-, 7-O-Ac-, and 9-O-Ac esters of N-glycolylneuraminic acid (Neu5Gc) residues. The presence of a new sialic acid derivative, identified by 1H NMR as 9-O-acetyl-2-keto-3-deoxy-D-glycero-D-galacto-nononic acid (trivial name, 9-O-acetyldeaminated neuraminic acid; 9-O-Ac-KDN), was also shown to be present as a minor component. The O-acetylated KDN residues appear to cap the nonreducing termini of the O-acetylated poly(Neu5Gc) chains. The O-acetylated polySia chains were resistant to depolymerization by bacterial exosialidases and a bacteriophage-derived endo-N-acylneuraminidase that is specific for catalyzing the hydrolysis of alpha -2,8-linkages in polySia containing either N-acetylneuraminic acid or Neu5Gc residues. After de-O-acetylation by mild alkali, the polySia chains were sensitive to digestion by endo-N-acylneuraminidase, yet partially resistant to exosialidase. These data confirm the alpha -2,8-ketosidic linkage in these chains and the nonreducing terminal location of the KDN residues. These results extend further the range of structural diversity in polySia-containing glycoconjugates, and in the family of naturally occurring sialic acids. They also suggest that the O-acetylated Neu5Gc and 9-O-Ac-KDN residues may have an important role during oogenesis.

  5. Large scale biosynthesis of ganglioside analogues by RERF-LC-AI cells cultured in HYPERFlask.

    PubMed

    Shimura, Yumiko; Suzuki, Junya; Muraoka, Miho; Kasuya, Maria Carmelita Zulueta; Matsuoka, Koji; Hatanaka, Kenichi

    2012-01-01

    The efficient production of ganglioside analogues was accomplished using RERF-LC-AI cells cultured in HYPERFlask (High Yield PERformance Flask). Eight kinds of ganglioside analogues (GM3, GM2, sialylparagloboside, GD3, di-sialylated lacto-N-tetraose, and another three kinds of analogues with intricate structures) were synthesized by the saccharide primer method using lung squamous-cell carcinoma line RERF-LC-AI and 12-azidododecyl β-lactoside primer. The yield for each analogue obtained using HYPERFlask was higher than yields obtained from 100-mm dishes.

  6. Lactational changes in concentration and distribution of ganglioside molecular species in human breast milk from Chinese mothers.

    PubMed

    Ma, Lin; Liu, Xihong; MacGibbon, Alastair K H; Rowan, Angela; McJarrow, Paul; Fong, Bertram Y

    2015-11-01

    Gangliosides play a critical role in human brain development and function. Human breast milk (HBM) is an important dietary source of gangliosides for the growing infant. In this study, ganglioside concentrations were measured in the breast milk from a cross-sectional sample of Chinese mothers over an 8-month lactation period. The average total ganglioside concentration increased from 13.1 mg/l during the first month to 20.9 mg/l by 8 months of lactation. The average concentration during the typically solely breast-feeding period of 1‒6 months was 18.9 mg/l. This is the first study to report the relative distribution of the individual ganglioside molecular species through lactation for any population group. The ganglioside molecular species are made up of different fatty acid moieties that influence the physical properties of these gangliosides, and hence affect their function. The GM(3) molecular species containing long-chain acyl fatty acids had the most prominent changes, increasing in both concentration and relative distribution. The equivalent long-chain acyl fatty acid GD(3) molecular species typically decreased in concentration and relative distribution. The lactational trends for both concentration and relative distribution for the very long-chain acyl fatty acid molecular species were more varied. The major GM(3) and GD(3) molecular species during lactation were d40:1 and d42:1, respectively. An understanding of ganglioside molecular species distribution in HBM is essential for accurate application of mass spectrometry methods for ganglioside quantification.

  7. Escherichia coli O157:H7 Strain EDL933 Harbors Multiple Functional Prophage-Associated Genes Necessary for the Utilization of 5-N-Acetyl-9-O-Acetyl Neuraminic Acid as a Growth Substrate

    PubMed Central

    Saile, Nadja; Voigt, Anja; Kessler, Sarah; Stressler, Timo; Fischer, Lutz

    2016-01-01

    ABSTRACT Enterohemorrhagic Escherichia coli (EHEC) O157:H7 strain EDL933 harbors multiple prophage-associated open reading frames (ORFs) in its genome which are highly homologous to the chromosomal nanS gene. The latter is part of the nanCMS operon, which is present in most E. coli strains and encodes an esterase which is responsible for the monodeacetylation of 5-N-acetyl-9-O-acetyl neuraminic acid (Neu5,9Ac2). Whereas one prophage-borne ORF (z1466) has been characterized in previous studies, the functions of the other nanS-homologous ORFs are unknown. In the current study, the nanS-homologous ORFs of EDL933 were initially studied in silico. Due to their homology to the chromosomal nanS gene and their location in prophage genomes, we designated them nanS-p and numbered the different nanS-p alleles consecutively from 1 to 10. The two alleles nanS-p2 and nanS-p4 were selected for production of recombinant proteins, their enzymatic activities were investigated, and differences in their temperature optima were found. Furthermore, a function of these enzymes in substrate utilization could be demonstrated using an E. coli C600ΔnanS mutant in a growth medium with Neu5,9Ac2 as the carbon source and supplementation with the different recombinant NanS-p proteins. Moreover, generation of sequential deletions of all nanS-p alleles in strain EDL933 and subsequent growth experiments demonstrated a gene dose effect on the utilization of Neu5,9Ac2. Since Neu5,9Ac2 is an important component of human and animal gut mucus and since the nutrient availability in the large intestine is limited, we hypothesize that the presence of multiple Neu5,9Ac2 esterases provides them a nutrient supply under certain conditions in the large intestine, even if particular prophages are lost. IMPORTANCE In this study, a group of homologous prophage-borne nanS-p alleles and two of the corresponding enzymes of enterohemorrhagic E. coli (EHEC) O157:H7 strain EDL933 that may be important to provide

  8. Ganglioside Profiling of the Human Retina: Comparison with Other Ocular Structures, Brain and Plasma Reveals Tissue Specificities

    PubMed Central

    Sibille, Estelle; Berdeaux, Olivier; Martine, Lucy; Bron, Alain M.; Creuzot-Garcher, Catherine P.; He, Zhiguo; Thuret, Gilles; Bretillon, Lionel; Masson, Elodie A. Y.

    2016-01-01

    Gangliosides make a wide family of glycosphingolipids, highly heterogeneous in both the ceramide moiety and the oligosaccharide chain. While ubiquitously expressed in mammalian tissues, they are particularly abundant in the brain and the peripheral nervous system. Gangliosides are known to play a crucial role in the development, maintenance and functional integrity of the nervous system. However, the expression and roles of gangliosides in the retina, although often considered as a window on the brain, has been far less studied. We performed an in-depth analysis of gangliosides of the human retina, especially using powerful LC/MS methods. We compared the pattern of ganglioside classes and ceramide molecular species of this tissue with other ocular structures and with brain and plasma in elderly human individuals. About a hundred of ganglioside molecular species among 15 distinct classes were detected illustrating the huge structural diversity of these compounds. The retina exhibited a very diverse ganglioside profile and shared several common features with the brain (prominence of tetraosylgangliosides, abundance of d20:1 long chain base and 18:0 fatty acid…). However, the retina stood out with the specific expression of GD3, GT3 and AcGT3, which further presented a peculiar molecular species distribution. The unique ganglioside pattern we observed in the human retina suggests that these ganglioside species play a specific role in the structure and function of this tissue. This lipidomic study, by highlighting retina specific ganglioside species, opens up novel research directions for a better understanding of the biological role of gangliosides in the retina. PMID:27997589

  9. Studies on Human Platelet Gangliosides

    PubMed Central

    Marcus, Aaron J.; Ullman, Harris L.; Safier, Lenore B.

    1972-01-01

    Gangliosides, glycosphingolipids which contain sialic acid, were studied in human platelets. They represented 0.5% of the platelet lipids and accounted for 6% of the total neuraminic acid content of platelets. Three major ganglioside fractions were identified and characterized. Ganglioside I was hematoside (G6) and comprised 92% of the platelet gangliosides. It contained glucose, galactose, and sialic acid in molar ratios of 1:1:1 and no hexosamine. The major fatty acid was behenate (22:0). Ganglioside I was also identified in isolated platelet granules and membranes. Ganglioside II (5%) contained glucose, galactose, sialic acid, and hexosamines (molar ratios 1:2:1:1). The hexosamines were glucosamine (72%) and galactosamine (28%). It was therefore designated as ganglioside lacto-N-neotetraose. Ganglioside III (2%) contained disialosyllactosyl ceramide (G3A) as well as two other gangliosides which could not be precisely characterized. Gangliosides I, II, and III were susceptible to the action of Clostridium perfringens neuraminidase as evidenced by full recovery of sialic acid in its free form after incubation. Neutral platelet glycolipids were qualitatively examined by thin-layer chromatography. The major component was lactosyl ceramide. Interactions of gangliosides I and III and serotonin-14C were examined in an equilibrium dialysis system at 4°C. The gangliosides bound serotonin-14C in relatively small quantities, whereas control lipids were negative. The binding was essentially unchanged by reverse dialysis, ultracentrifugation and subsequent thin-layer chromatography. The results are comparable to the previously observed nonmetabolic interactions between whole platelets and serotonin in the cold. It is suggested that the orientation and specific distribution of platelet membrane glycolipids may be important determinants of the unique surface properties of platelets. Images PMID:4341436

  10. Neutral glycolipid and ganglioside composition of type-1 and type-2 astrocytes from rat cerebral hemisphere.

    PubMed

    Murakami, K; Asou, H; Adachi, T; Takagi, T; Kunimoto, M; Saito, H; Uyemura, K

    1999-02-01

    We reported previously that the major gangliosides in primary mixed-type astrocyte cultures are GM3 and GD3. To obtain more information regarding the exact distribution of glycosphingolipids in different types of astrocytes, we established a line of type-1 astrocytes that are characterized by a Ran-2 positive, broad flat morphology, and by the absence of binding to A2B5 antibodies. We also purified O-2A progenitor cells by immunopanning and cultured them in the presence of 10% newborn calf serum. They differentiated into type-2 astrocytes that were identified by immunostaining for each of GD3, A2B5, and GFAP. Using these cell cultures, we demonstrate that the major gangliosides were GM3 in type-1 astrocytes and GM3 and GD3 in type-2 astrocytes. In addition, a set of neutral glycolipids was identified based on the HP-TLC migration properties of CMH, CDH, CTH, and Glob, but the component distribution of these glycolipids is related to that of glycolipids of astrocytes. A marked increase in the expression of CTH and Glob was shown in type-2 astrocytes. The amount of neutral glycolipid-sugar was higher in the type-2 astrocytes than in the type-1 astrocytes. These results suggest that the increase in the total glycosphingolipid content and the change in the neutral glycolipid composition produced by type-2 astrocytes may be related to their biological functions and the cellular compositions.

  11. Alpha-N-acetyl-neuraminide alpha-2,8-sialyltransferase 1 can support immune responses toward tumors overexpressing ganglioside D3 in mice.

    PubMed

    Eby, Jonathan M; Barse, Levi; Henning, Steven W; Rabelink, Martijn J W E; Klarquist, Jared; Gilbert, Emily R; Hammer, Adam M; Fernandez, Manuel F; Yung, Nathan; Khan, Safia; Miller, Hannah G; Kessler, Edward R; Garrett-Mayer, Elizabeth; Dilling, Daniel F; Hoeben, Rob C; Le Poole, I Caroline

    2017-01-01

    An immunotherapeutic strategy is discussed supporting anti-tumor activity toward malignancies overexpressing ganglioside D3. GD3 can be targeted by NKT cells when derived moieties are presented in the context of CD1d. NKT cells can support anti-tumor responses by secreting inflammatory cytokines and through cytotoxicity toward CD1d(+)GD3(+) tumors. To overexpress GD3, we generated expression vector DNA and an adenoviral vector encoding the enzyme responsible for generating GD3 from its ubiquitous precursor GM3. We show that DNA encoding α-N-acetyl-neuraminide α-2,8-sialyltransferase 1 (SIAT8) introduced by gene gun vaccination in vivo leads to overexpression of GD3 and delays tumor growth. Delayed tumor growth is dependent on CD1d expression by host immune cells, as shown in experiments engaging CD1d knockout mice. A trend toward greater NKT cell populations among tumor-infiltrating lymphocytes is associated with SIAT8 vaccination. A single adenoviral vaccination introduces anti-tumor activity similarly to repeated vaccination with naked DNA. Here, greater NKT tumor infiltrates were accompanied by marked overexpression of IL-17 in the tumor, later switching to IL-4. Our results suggest that a single intramuscular adenoviral vaccination introduces overexpression of GD3 by antigen-presenting cells at the injection site, recruiting NKT cells that provide an inflammatory anti-tumor environment. We propose adenoviral SIAT8 (AdV-SIAT8) can slow the growth of GD3 expressing tumors in patients.

  12. Quantitative analysis of gangliosides in bovine milk and colostrum-based dairy products by ultrahigh performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Lee, Hyeyoung; German, J Bruce; Kjelden, Randy; Lebrilla, Carlito B; Barile, Daniela

    2013-10-09

    Milk gangliosides have gained considerable attention because they participate in diverse biological processes, including neural development, pathogen binding, and activation of the immune system. Herein, we present a quantitative measurement of the gangliosides present in bovine milk and other dairy products and byproducts. Ultrahigh performance liquid chromatography separation was used for high-throughput analysis and achieved a short running time without sacrificing chromatographic resolution. Dynamic multiple reaction monitoring was conducted for 12 transitions for GM3 and 12 transitions for GD3. Transitions to sialic acid fragments (m/z 290.1) were chosen for the quantitation. There was a considerable amount of gangliosides in day 2 milk (GM3, 0.98 mg/L; GD3, 15.2 mg/L) which dramatically decreased at day 15 and day 90. GM3 and GD3 were also analyzed in pooled colostrum, colostrum cream, colostrum butter, and colostrum buttermilk. The separation and analytical approaches here proposed could be integrated into the dairy industry processing adding value to side-streams.

  13. Ganglioside accumulation in activated glia in the developing brain: comparison between WT and GalNAcT KO mice.

    PubMed

    Saito, Mariko; Wu, Gusheng; Hui, Maria; Masiello, Kurt; Dobrenis, Kostantin; Ledeen, Robert W; Saito, Mitsuo

    2015-08-01

    Our previous studies have shown accumulation of GM2 ganglioside during ethanol-induced neurodegeneration in the developing brain, and GM2 elevation has also been reported in other brain injuries and neurodegenerative diseases. Using GM2/GD2 synthase KO mice lacking GM2/GD2 and downstream gangliosides, the current study explored the significance of GM2 elevation in WT mice. Immunohistochemical studies indicated that ethanol-induced acute neurodegeneration in postnatal day 7 (P7) WT mice was associated with GM2 accumulation in the late endosomes/lysosomes of both phagocytic microglia and increased glial fibrillary acidic protein (GFAP)-positive astrocytes. However, in KO mice, although ethanol induced robust neurodegeneration and accumulation of GD3 and GM3 in the late endosomes/lysosomes of phagocytic microglia, it did not increase the number of GFAP-positive astrocytes, and the accumulation of GD3/GM3 in astrocytes was minimal. Not only ethanol, but also DMSO, induced GM2 elevation in activated microglia and astrocytes along with neurodegeneration in P7 WT mice, while lipopolysaccharide, which did not induce significant neurodegeneration, caused GM2 accumulation mainly in lysosomes of activated astrocytes. Thus, GM2 elevation is associated with activation of microglia and astrocytes in the injured developing brain, and GM2, GD2, or other downstream gangliosides may regulate astroglial responses in ethanol-induced neurodegeneration.

  14. Ganglioside accumulation in activated glia in the developing brain: comparison between WT and GalNAcT KO mice

    PubMed Central

    Saito, Mariko; Wu, Gusheng; Hui, Maria; Masiello, Kurt; Dobrenis, Kostantin; Ledeen, Robert W.; Saito, Mitsuo

    2015-01-01

    Our previous studies have shown accumulation of GM2 ganglioside during ethanol-induced neurodegeneration in the developing brain, and GM2 elevation has also been reported in other brain injuries and neurodegenerative diseases. Using GM2/GD2 synthase KO mice lacking GM2/GD2 and downstream gangliosides, the current study explored the significance of GM2 elevation in WT mice. Immunohistochemical studies indicated that ethanol-induced acute neurodegeneration in postnatal day 7 (P7) WT mice was associated with GM2 accumulation in the late endosomes/lysosomes of both phagocytic microglia and increased glial fibrillary acidic protein (GFAP)-positive astrocytes. However, in KO mice, although ethanol induced robust neurodegeneration and accumulation of GD3 and GM3 in the late endosomes/lysosomes of phagocytic microglia, it did not increase the number of GFAP-positive astrocytes, and the accumulation of GD3/GM3 in astrocytes was minimal. Not only ethanol, but also DMSO, induced GM2 elevation in activated microglia and astrocytes along with neurodegeneration in P7 WT mice, while lipopolysaccharide, which did not induce significant neurodegeneration, caused GM2 accumulation mainly in lysosomes of activated astrocytes. Thus, GM2 elevation is associated with activation of microglia and astrocytes in the injured developing brain, and GM2, GD2, or other downstream gangliosides may regulate astroglial responses in ethanol-induced neurodegeneration. PMID:26063460

  15. Rapid Profiling of Bovine and Human Milk Gangliosides by Matrix-Assisted Laser Desorption/Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

    PubMed Central

    Lee, Hyeyoung; An, Hyun Joo; Lerno, Larry A.; German, J. Bruce; Lebrilla, Carlito B.

    2010-01-01

    Gangliosides are anionic glycosphingolipids widely distributed in vertebrate tissues and fluids. Their structural and quantitative expression patterns depend on phylogeny and are distinct down to the species level. In milk, gangliosides are exclusively associated with the milk fat globule membrane. They may participate in diverse biological processes but more specifically to host-pathogen interactions. However, due to the molecular complexities, the analysis needs extensive sample preparation, chromatographic separation, and even chemical reaction, which makes the process very complex and time-consuming. Here, we describe a rapid profiling method for bovine and human milk gangliosides employing matrix-assisted desorption/ionization (MALDI) Fourier transform ion cyclotron resonance (FTICR) mass spectrometry (MS). Prior to the analyses of biological samples, milk ganglioside standards GM3 and GD3 fractions were first analyzed in order to validate this method. High mass accuracy and high resolution obtained from MALDI FTICR MS allow for the confident assignment of chain length and degree of unsaturation of the ceramide. For the structural elucidation, tandem mass spectrometry (MS/MS), specifically as collision-induced dissociation (CID) and infrared multiphoton dissociation (IRMPD) were employed. Complex ganglioside mixtures from bovine and human milk were further analyzed with this method. The samples were prepared by two consecutive chloroform/methanol extraction and solid phase extraction. We observed a number of differences between bovine milk and human milk. The common gangliosides in bovine and human milk are NeuAc-NeuAc-Hex-Hex-Cer (GD3) and NeuAc-Hex-Hex-Cer (GM3); whereas, the ion intensities of ganglioside species are different between two milk samples. Kendrick mass defect plot yields grouping of ganglioside peaks according to their structural similarities. Gangliosides were further probed by tandem MS to confirm the compositional and structural assignments

  16. Activation of human naïve Th cells increases surface expression of GD3 and induces neoexpression of GD2 that colocalize with TCR clusters.

    PubMed

    Villanueva-Cabello, Tania M; Mollicone, Rosella; Cruz-Muñoz, Mario E; López-Guerrero, Delia V; Martínez-Duncker, Iván

    2015-12-01

    CD4+ T helper lymphocytes (Th) orchestrate the immune response after their activation by antigen-presenting cells. Activation of naïve Th cells is reported to generate the reduction in surface epitopes of sialic acid (Sia) in α2,3 and α2,6 linkages. In this work, we report that in spite of this glycophenotype, anti-CD3/anti-CD28-activated purified human naïve Th cells show a significant increase in surface Sia, as assessed by metabolic labeling, compared with resting naïve Th cells, suggesting an increased flux of Sia toward Siaα2,8 glycoconjugates. To understand this increase as a result of ganglioside up-regulation, we observed that very early after activation, human naïve Th cells show an increased expression in surface GD3 and neoexpression of surface GD2 gangliosides, the latter clustering with the T cell receptor (TCR). Also, we report that in contrast to GM2/GD2 synthase null mice, lentiviral vector-mediated silencing of the GM2/GD2 synthase in activated human naïve Th cells reduced efficient TCR clustering and downstream signaling, as assessed by proliferation assays and IL-2 and IL-2R expression, pointing to an important role of this enzyme in activation of human naive Th cells.

  17. Ganglioside mimicry and peripheral nerve disease.

    PubMed

    Yuki, Nobuhiro

    2007-06-01

    Four criteria must be satisfied to conclude that a given microorganism causes Guillain-Barré (GBS) or Fisher (FS) syndrome associated with anti-ganglioside antibodies: (1) an epidemiological association between the infecting microbe and GBS or FS; (2) isolation in the acute progressive phase of illness of that microorganism from GBS or FS patients with associated anti-ganglioside IgG antibodies; (3) identification of a microbial ganglioside mimic; and (4) a GBS or FS with associated anti-ganglioside antibodies model produced by sensitization with the microbe itself or its component, as well as with ganglioside. Campylobacter jejuni is a definitive causative microorganism of acute motor axonal neuropathy and may cause FS and related conditions. Haemophilus influenzae and Mycoplasma pneumoniae are possible causative microorganisms of acute motor axonal neuropathy or FS. Acute and chronic inflammatory demyelinating polyneuropathies may be produced by mechanisms other than ganglioside mimicry.

  18. Differentiation of oligodendrocytes cultured from developing rat brain is enhanced by exogenous GM3 ganglioside.

    PubMed

    Yim, S H; Farrer, R G; Hammer, J A; Yavin, E; Quarles, R H

    1994-06-15

    Cultures consisting primarily of O-2A progenitor cells and immature oligodendrocytes with a few microglia and astrocytes were obtained by shaking primary cultures from neonatal rat brain after 12-14 days in vitro. Addition of 50 micrograms/ml exogenous Neu-NAc alpha 2-3Gal beta 1-4Glc beta 1-1'ceramide (GM3 ganglioside) to the cultures resulted in an increase in the number and thickness of cell processes that stained intensely for sulfatide and galactocerebroside (galC) in comparison to control cultures without added GM3. The treated cultures also contained fewer astrocytes than control cultures as revealed by immunostaining for glial fibrillary acidic protein (GFAP). Cells that immunostained for both GFAP and sulfatide/galC were very rare in control cultures but were frequently seen in the GM3-treated cultures, suggesting that these may represent cells changing their direction of differentiation away from type II astrocytes toward oligodendrocytes under the influence of GM3. These effects on the developing rat oligodendrocytes were specific for GM3 ganglioside and were not produced by adding GM1, GM2, GD3, or GD1a to the cultures. Lactosyl ceramide and neuraminyl lactose were also ineffective. When control cultures were initially plated on polylysine and incubated with [14C]galactose, GD3 was the principal labeled ganglioside. However, as the control cells differentiated over time in culture without the addition of exogenous GM3 and produced increasing amounts of myelin-related components, the incorporation of [14C]galactose into endogenous GM3 increased to become the predominant labeled ganglioside by 6 days after plating. Metabolic labeling of the GM3-treated oligodendrocytes with [14C]galactose revealed increased incorporation into galC and sulfatide in comparison to control cultures, but a decreased labeling of endogenous GM3. Similarly, incorporation of an amino acid precursor into the myelin-associated glycoprotein (MAG) was increased by GM3 treatment, but

  19. Unique Ganglioside Recognition Strategies for Clostridial Neurotoxins

    SciTech Connect

    Benson, Marc A.; Fu, Zhuji; Kim, Jung-Ja P.; Baldwin, Michael R.

    2012-03-15

    Botulinum neurotoxins (BoNTs) and tetanus neurotoxin are the causative agents of the paralytic diseases botulism and tetanus, respectively. The potency of the clostridial neurotoxins (CNTs) relies primarily on their highly specific binding to nerve terminals and cleavage of SNARE proteins. Although individual CNTs utilize distinct proteins for entry, they share common ganglioside co-receptors. Here, we report the crystal structure of the BoNT/F receptor-binding domain in complex with the sugar moiety of ganglioside GD1a. GD1a binds in a shallow groove formed by the conserved peptide motif E ... H ... SXWY ... G, with additional stabilizing interactions provided by two arginine residues. Comparative analysis of BoNT/F with other CNTs revealed several differences in the interactions of each toxin with ganglioside. Notably, exchange of BoNT/F His-1241 with the corresponding lysine residue of BoNT/E resulted in increased affinity for GD1a and conferred the ability to bind ganglioside GM1a. Conversely, BoNT/E was not able to bind GM1a, demonstrating a discrete mechanism of ganglioside recognition. These findings provide a structural basis for ganglioside binding among the CNTs and show that individual toxins utilize unique ganglioside recognition strategies.

  20. Ceramide structure predicts tumor ganglioside immunosuppressive activity.

    PubMed Central

    Ladisch, S; Li, R; Olson, E

    1994-01-01

    Molecular determinants of biological activity of gangliosides are generally believed to be carbohydrate in nature. However, our studies of immunomodulation by highly purified naturally occurring tumor gangliosides provide another perspective: while the immunosuppressive activity of gangliosides requires the intact molecule (both carbohydrate and ceramide moieties), ceramide structure strikingly influences ganglioside immunosuppressive activity. Molecular species of human neuroblastoma GD2 ganglioside in which the ceramide contains a shorter fatty acyl chain (C16:0, C18:0) were 6- to 10-fold more active than those with a longer fatty acyl chain (C22:0/C24:1, C24:0). These findings were confirmed in studies of ceramide species of human leukemia sialosylparagloboside and murine lymphoma GalNAcGM1b. Gangliosides that contain shorter-chain fatty acids (and are most immunosuppressive) are known to be preferentially shed by tumor cells. Therefore, the results suggest that the tumor cell is optimized to protect itself from host immune destruction by selective shedding of highly active ceramide species of gangliosides. Images PMID:8127917

  1. Ganglioside Regulation of AMPA Receptor Trafficking

    PubMed Central

    Prendergast, Jillian; Umanah, George K.E.; Yoo, Seung-Wan; Lagerlöf, Olof; Motari, Mary G.; Cole, Robert N.; Huganir, Richard L.; Dawson, Ted M.; Dawson, Valina L.

    2014-01-01

    Gangliosides are major cell-surface determinants on all vertebrate neurons. Human congenital disorders of ganglioside biosynthesis invariably result in intellectual disability and are often associated with intractable seizures. To probe the mechanisms of ganglioside functions, affinity-captured ganglioside-binding proteins from rat cerebellar granule neurons were identified by quantitative proteomic mass spectrometry. Of the six proteins that bound selectively to the major brain ganglioside GT1b (GT1b:GM1 > 4; p < 10−4), three regulate neurotransmitter receptor trafficking: Thorase (ATPase family AAA domain-containing protein 1), soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein (γ-SNAP), and the transmembrane protein Nicalin. Thorase facilitates endocytosis of GluR2 subunit-containing AMPA-type glutamate receptors (AMPARs) in an ATPase-dependent manner; its deletion in mice results in learning and memory deficits (J. Zhang et al., 2011b). GluR2-containing AMPARs did not bind GT1b, but bound specifically to another ganglioside, GM1. Addition of noncleavable ATP (ATPγS) significantly disrupted ganglioside binding, whereas it enhanced AMPAR association with Thorase, NSF, and Nicalin. Mutant mice lacking GT1b expressed markedly higher brain Thorase, whereas Thorase-null mice expressed higher GT1b. Treatment of cultured hippocampal neurons with sialidase, which cleaves GT1b (and other sialoglycans), resulted in a significant reduction in the size of surface GluR2 puncta. These data support a model in which GM1-bound GluR2-containing AMPARs are functionally segregated from GT1b-bound AMPAR-trafficking complexes. Release of ganglioside binding may enhance GluR2-containing AMPAR association with its trafficking complexes, increasing endocytosis. Disrupting ganglioside biosynthesis may result in reduced synaptic expression of GluR2-contianing AMPARs resulting in intellectual deficits and seizure susceptibility in mice and humans. PMID:25253868

  2. Ganglioside regulation of AMPA receptor trafficking.

    PubMed

    Prendergast, Jillian; Umanah, George K E; Yoo, Seung-Wan; Lagerlöf, Olof; Motari, Mary G; Cole, Robert N; Huganir, Richard L; Dawson, Ted M; Dawson, Valina L; Schnaar, Ronald L

    2014-09-24

    Gangliosides are major cell-surface determinants on all vertebrate neurons. Human congenital disorders of ganglioside biosynthesis invariably result in intellectual disability and are often associated with intractable seizures. To probe the mechanisms of ganglioside functions, affinity-captured ganglioside-binding proteins from rat cerebellar granule neurons were identified by quantitative proteomic mass spectrometry. Of the six proteins that bound selectively to the major brain ganglioside GT1b (GT1b:GM1 > 4; p < 10(-4)), three regulate neurotransmitter receptor trafficking: Thorase (ATPase family AAA domain-containing protein 1), soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein (γ-SNAP), and the transmembrane protein Nicalin. Thorase facilitates endocytosis of GluR2 subunit-containing AMPA-type glutamate receptors (AMPARs) in an ATPase-dependent manner; its deletion in mice results in learning and memory deficits (J. Zhang et al., 2011b). GluR2-containing AMPARs did not bind GT1b, but bound specifically to another ganglioside, GM1. Addition of noncleavable ATP (ATPγS) significantly disrupted ganglioside binding, whereas it enhanced AMPAR association with Thorase, NSF, and Nicalin. Mutant mice lacking GT1b expressed markedly higher brain Thorase, whereas Thorase-null mice expressed higher GT1b. Treatment of cultured hippocampal neurons with sialidase, which cleaves GT1b (and other sialoglycans), resulted in a significant reduction in the size of surface GluR2 puncta. These data support a model in which GM1-bound GluR2-containing AMPARs are functionally segregated from GT1b-bound AMPAR-trafficking complexes. Release of ganglioside binding may enhance GluR2-containing AMPAR association with its trafficking complexes, increasing endocytosis. Disrupting ganglioside biosynthesis may result in reduced synaptic expression of GluR2-contianing AMPARs resulting in intellectual deficits and seizure susceptibility in mice and humans.

  3. Surface enhanced Raman scattering of amino acids assisted by gold nanoparticles and Gd(3+) ions.

    PubMed

    López-Neira, Juan Pablo; Galicia-Hernández, José Mario; Reyes-Coronado, Alejandro; Pérez, Elías; Castillo-Rivera, Francisco

    2015-05-07

    The surface enhanced raman scattering (SERS) signal from the l-tyrosine (tyr) molecule adsorbed on gold nanoparticles (Au-tyr) is compared with the SERS signal assisted by the presence of gadolinium ions (Gd(3+)) coordinated with the Au-tyr system. An enhancement factor of the SERS signal in the presence of Gd(3+) ions was ∼5 times higher than that produced by l-tyrosine adsorbed on gold nanoparticles. The enhancement of the SERS signal can be attributed to a corresponding increase in the local electric field due to the presence of Gd(3+) ions in the vicinity of a gold dimer configuration. This scenario was confirmed by solving numerically Maxwell equations, showing an increase of 1 order of magnitude in the local electric scattered field when the Gd(3+) ion is located in between a gold dimer compared with naked gold nanoparticles.

  4. Influence of dietary gangliosides on neonatal brain development.

    PubMed

    McJarrow, Paul; Schnell, Nicholas; Jumpsen, Jacqueline; Clandinin, Tom

    2009-08-01

    Gangliosides are sialic acid-containing glycosphingolipids. Gangliosides are found in human milk; understanding of the potential role of gangliosides in infant development is emerging, with suggested roles in the brain and gut. Ganglioside accretion in the developing brain is highest in utero and in early neonatal life, during the periods of dendritic branching and new synapse formation. Further, brain contains the highest relative ganglioside content in the body, particularly in neuronal cell membranes concentrated in the area of the synaptic membrane. Gangliosides are known to play a role in neuronal growth, migration and maturation, neuritogenesis, synaptogenesis, and myelination. In addition to their roles in development and structure of the brain, gangliosides also play a functional role in nerve cell communication. It is less well known whether dietary gangliosides can influence the development of cognitive function. This review summarizes current knowledge on the role gangliosides play in brain development.

  5. Structural and magnetic properties of Gd3+ ion substituted magnesium ferrite nanopowders

    NASA Astrophysics Data System (ADS)

    Elkady, Ashraf S.; Hussein, Shaban I.; Rashad, Mohamed M.

    2015-07-01

    Nanocrystalline MgGdxFe2-xO4 powders (where x=0, 0.05, 0.1, 0.2, 0.25, 0.3) have been synthesized by the ethylene diamine tetraacetic acid (EDTA)-based sol-gel combustion method. X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, high resolution transmission electron microscopy (HRTEM) and vibrating sample magnetometer (VSM) were applied in order to study the effect of variation of Gd3+ ion substitution and its impact on crystal structure, crystallite size, lattice parameters, nanostructure and magnetic properties of the formed powders. XRD indicated that, after doping and calcination at 400 °C for 2 h, all samples have two spinel ferrite structures namely cubic and tetragonal phases, which are dependent on Gd3+ ion concentration. The cubic phase is found to increase with increasing the Gd3+ ion molar ratio up to 0.1, compared to pure MgFe2O4 and higher Gd3+ content samples. Indeed, with increasing Gd3+ ion, the crystallite size was almost unchanged whereas the lattice parameter was found to increase. FT-IR spectrum showed broadening of the ν2 band and the presence of another band in the range (465-470 cm-1) upon adding Gd3+ ion, which confirm the presence of Gd3+ ion in addition to Fe3+ ion at octahedral site. Besides, these bands were assigned to the formation of (Gd3+-O2-) complexes at B-sites. HRTEM images showed that the studied samples consist of nanocrystallites having average particle sizes around 9 nm for pure MgFe2O4 up to 27 and 42 nm for the Gd3+ ion substituted MgFe2O4 of molar ratio 0.05 and 0.30, respectively. An examination of the magnetic properties revealed an increase in saturation magnetization with increasing Gd concentration incorporation up to x=0.1, as a result of the change of cubic and tetragonal spinel ratio and lattice parameters. Meanwhile, the formed powders exhibited superparamagnetic characteristics. Therefore, such newly synthesized superparamagnetic nanoparticles, containing Gd3+ ion can be considered as a

  6. Circulating gangliosides of breast-cancer patients.

    PubMed

    Wiesner, D A; Sweeley, C C

    1995-01-27

    Gangliosides were isolated from the sera of recently diagnosed breast-cancer patients and from individuals who were apparently free of disease. Quantificative and qualitative analyses were carried out by 2-dimensional high-performance thin-layer chromatography and gas chromatography. The locations of isolated gangliosides on thin-layer chromatograms were determined by visualization with resorcinol, and each spot was quantified by digital image densitometry. The ganglioside profiles of cancer patients were compared to those of the control group, revealing a significant increase in total lipid-bound sialic acid and a specific increase in polysialogangliosides in the patients with breast cancer. Furthermore, an increase was noted in the ratio of gangliosides of the b-series biosynthetic pathway over those of the a-series in the cancer sera, as compared to the controls. Gas chromatographic analysis of the peracetylated methanolysis mixtures derived from the total ganglioside fraction of cancer patients supported the HPTLC data, with an increase in total sialic acid, galactose, and sphingosine residues. No unusual gangliosides were found in the mixture from breast-cancer patients.

  7. Physiopathological function of hematoside (GM3 ganglioside)

    PubMed Central

    INOKUCHI, Jin-ichi

    2011-01-01

    Since I was involved in the molecular cloning of GM3 synthase (SAT-I), which is the primary enzyme for the biosynthesis of gangliosides in 1998, my research group has been concentrating on our efforts to explore the physiological and pathological implications of gangliosides especially for GM3. During the course of study, we demonstrated the molecular pathogenesis of type 2 diabetes and insulin resistance focusing on the interaction between insulin receptor and gangliosides in membrane microdomains and propose a new concept: Life style-related diseases, such as type 2 diabetes, are a membrane microdomain disorder caused by aberrant expression of gangliosides. We also encountered an another interesting aspect indicating the indispensable role of gangliosides in auditory system. After careful behavioral examinations of SAT-I knockout mice, their hearing ability was seriously impaired with selective degeneration of the stereocilia of hair cells in the organ of Corti. This is the first observation demonstrating a direct link between gangliosides and hearing functions. PMID:21558756

  8. Elevation of GM2 ganglioside during ethanol-induced apoptotic neurodegeneration in the developing mouse brain.

    PubMed

    Saito, Mitsuo; Chakraborty, Goutam; Shah, Relish; Mao, Rui-Fen; Kumar, Asok; Yang, Dun-Sheng; Dobrenis, Kostantin; Saito, Mariko

    2012-05-01

    GM2 ganglioside in the brain increased during ethanol-induced acute apoptotic neurodegeneration in 7-day-old mice. A small but a significant increase observed 2 h after ethanol exposure was followed by a marked increase around 24 h. Subcellular fractionation of the brain 24 h after ethanol treatment indicated that GM2 increased in synaptic and non-synaptic mitochondrial fractions as well as in a lysosome-enriched fraction characteristic to the ethanol-exposed brain. Immunohistochemical staining of GM2 in the ethanol-treated brain showed strong punctate staining mainly in activated microglia, in which it partially overlapped with staining for LAMP1, a late endosomal/lysosomal marker. Also, there was weaker neuronal staining, which partially co-localized with complex IV, a mitochondrial marker, and was augmented in cleaved caspase 3-positive neurons. In contrast, the control brain showed only faint and diffuse GM2 staining in neurons. Incubation of isolated brain mitochondria with GM2 in vitro induced cytochrome c release in a manner similar to that of GD3 ganglioside. Because ethanol is known to trigger mitochondria-mediated apoptosis with cytochrome c release and caspase 3 activation in the 7-day-old mouse brain, the GM2 elevation in mitochondria may be relevant to neuroapoptosis. Subsequently, activated microglia accumulated GM2, indicating a close relationship between GM2 and ethanol-induced neurodegeneration.

  9. Recognition characteristics of monoclonal antibodies that are cross-reactive with gangliosides and lipooligosaccharide from Campylobacter jejuni strains associated with Guillain-Barré and Fisher syndromes.

    PubMed

    Houliston, R Scott; Yuki, Nobuhiro; Hirama, Tomoko; Khieu, Nam H; Brisson, Jean-Robert; Gilbert, Michel; Jarrell, Harold C

    2007-01-09

    The enteropathogen Campylobacter jejuni has the ability to synthesize glycan structures that are similar to mammalian gangliosides within the core component of its lipooligosaccharide (LOS). Exposure to ganglioside mimics in some individuals results in the production of autoantibodies that deleteriously attack nerve surface gangliosides, precipitating the onset of Guillain-Barré and Fisher syndromes (GBS and FS). We have characterized the interaction of four monoclonal antibodies (mAbs), established by sensitization of mice with LOS isolated from GBS- and FS-associated C. jejuni strains, with chemoenzymatically synthesized gangliooligosaccharides. Surface plasmon resonance (SPR) measurements demonstrate that three of the mAbs interact specifically with derivatives corresponding to their targeted gangliosides, with dissociation constants ranging from 10 to 20 microM. Antibody binding to the gangliooligosaccharides was probed by saturation transfer difference (STD) NMR spectroscopy. STD signals, resulting from antibody/oligosaccharide interaction, were observed for each of the four mAbs. In two cases, differential saturation transfer rates to oligosaccharide resonances enabled detailed epitope mapping. The binding of GD1a-S-Phe with GB1 is characterized by close association of the immunoglobulin with sites that are distributed over several residues of the oligosaccharide. This contrasts sharply with the profile observed for the binding of both GD3-S-Phe and GT1a-S-Phe with FS1. The close antigenic contacts in these ganglioside derivatives are confined to the N-acetylmannosaminyl portion of the terminal N-acetylneuraminic acid (NeuAc) residue of the disialosyl moiety. Our characterization of FS1 provides insight, at an atomic level, into how a single antigenic determinant presented by the LOS of C. jejuni can give rise to antibodies with binding promiscuity to [alphaNeuAc-(2-8)-alphaNeuAc]-bound epitopes and demonstrates why sera from FS patients have antibodies that

  10. Motor-dominant polyneuropathy due to IgM monoclonal antibody against disialosyl gangliosides in a patient with mantle cell lymphoma.

    PubMed

    Mori, Akio; Ueno, Yuji; Kuroki, Takuma; Hoshino, Yasunobu; Shimura, Hideki; Sekiguchi, Yasunobu; Noguchi, Masaaki; Hamada, Yukihiro; Kusunoki, Susumu; Hattori, Nobutaka; Urabe, Takao

    2014-02-15

    A rapidly progressive motor-dominant neuropathy associated with IgM monoclonal antibody against gangliosides with disialosyl residues, GD3, GD1b, GT1b, and GQ1b, in a 60-year-old Japanese man with mantle cell lymphoma is reported. Plasma exchange and chemotherapy for mantle cell lymphoma were performed for the neuropathy and mantle cell lymphoma. After therapy, the motor neuropathy dramatically improved concurrently with substantial reduction of the antibody activities especially in reaction to GD1b. This is the first case report of neuropathy with anti-disialosyl IgM antibodies associated with mantle cell lymphoma, and plasma exchange and chemotherapy were effective.

  11. EPR and optical absorption studies on Gd 3+ ions in ammonium hydrogen malonate single crystals

    NASA Astrophysics Data System (ADS)

    Kripal, Ram; Mishra, Indrajeet

    2010-01-01

    X-Band electron paramagnetic resonance (EPR) studies of Gd 3+ ions in ammonium hydrogen malonate single crystals have been done at room temperature. Detailed EPR analysis indicates the presence of four physically equivalent but magnetically inequivalent sites. The zero-field splitting parameters and g factor are determined. The Gd 3+ ion is in 8S state; its levels are split by the action of the crystalline electric field of monoclinic symmetry. The optical absorption spectra of Gd 3+ ions in single crystals of ammonium hydrogen malonate are also recorded at room temperature. The energy levels of the 4f 7 configuration are calculated and compared with those observed experimentally. The values of E1=5854±11, E2=31±0.36, E3=592±3.3 and ζ 4f=1595±25 cm -1 are found to give the best over-all agreement between experimentally observed and calculated levels.

  12. Gd3+ vibronic side band spectroscopy. New optical probe of Ca2+ binding sites applied to biological macromolecules.

    PubMed Central

    Iben, I E; Stavola, M; Macgregor, R B; Zhang, X Y; Friedman, J M

    1991-01-01

    A new spectroscopic technique is presented for obtaining infraredlike spectra of the binding sites of Ca2+ and other metals in biological macromolecules. The technique, based on the Ca(2+)-like binding properties of Gd3+, utilizes vibronic side bands (VSB) that appear in Gd3+ fluorescence. In the fluorescence spectrum of Gd3+, the separation in photon frequency between a VSB and its electronic origin at approximately 32,150 cm-1 (approximately 311 nm) is a direct measure of the vibrational frequency of a ligand coordinated to Gd3+ ion. As a consequence, the VSB are uncomplicated by molecular vibrations distant from the Gd3+ binding site. The vibrational spectra resulting from the VSB of Gd3+ coordinated to a Ca2+ binding protein, a phospholipid, and DNA are presented. PMID:1907866

  13. Gangliosides, or sialic acid, antagonize ethanol intoxication

    SciTech Connect

    Klemm, W.R.; Boyles, R.; Matthew, J.; Cherian, L.

    1988-01-01

    Because ethanol elicits a dose-dependent hydrolysis of brain sialogangliosides, the authors tested the possibility that injected gangliosides might antagonize intoxicating doses of ethanol. Clear anti-intoxication effects were seen at 24 hr post-injection of mixed mouse-brain gangliosides at 125-130 mg/kg, but not at lower or higher doses. Sleep time was reduced on the order of 50%, and roto-rod agility was significantly enhanced. Sialic acid (SA) similarly antagonized ethanol; however, the precursor of SA, N-acetyl-D-mannosamine, as well as ceramide and asialoganglioside did not.

  14. Nanostructured Gd3+-TiO2 surfaces for self-cleaning application

    NASA Astrophysics Data System (ADS)

    Saif, M.; El-Molla, S. A.; Aboul-Fotouh, S. M. K.; Ibrahim, M. M.; Ismail, L. F. M.; Dahn, Douglas C.

    2014-06-01

    Preparation of self-cleaning surfaces based on lanthanide modified titanium dioxide nanoparticles has rarely been reported. In the present work, gadolinium doped titanium dioxide thin films (x mol Gd3+-TiO2 where x = 0.000, 0.005, 0.008, 0.010, 0.020 and 0.030 mol) were synthesized by sol-gel method and deposited using doctor-blade method. These films were characterized by studying their structural, optical and electrical properties. Doping with gadolinium decreases the band gap energy and increase conductivity of thin films. The photo self-cleaning activity in term of quantitative determination of the active oxidative species (rad OH) produced on the thin film surfaces was evaluated using fluorescent probe method. The results show that, the highly active thin film is the 0.020 Gd3+-TiO2. The structural, morphology, optical, electrical and photoactivity properties of Gd3+-TiO2 thin films make it promising surfaces for self-cleaning application. Mineralization of commercial textile dye (Remazol Red RB-133, RR) and durability using 0.020Gd3+-TiO2 film surface was studied.

  15. Inter-atomic bonding and dielectric polarization in Gd3+ incorporated Co-Zn ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Pawar, R. A.; Desai, S. S.; Patange, S. M.; Jadhav, S. S.; Jadhav, K. M.

    2017-04-01

    A series of ferrite with a chemical composition Co0.7Zn0.3GdxFe2-xO4 (where x=0.0 to x=0.1) were prepared by sol-gel auto-combustion method. X-ray diffraction pattern were used to determine the crystal structure and phase formation of the prepared samples. Scanning electron microscopy is used to study the surface morphology of the prepared samples. Elastic properties were determined from the infrared spectroscopy. Debye temperature, wave velocities, elastic constants found to increase with the increase in Gd3+ substitution. Dielectric properties such as dielectric constant and dielectric loss were studied as a function of Gd3+ substitution and frequency. Dielectric constant decreased with the increase in frequency and Gd3+ substitution. Behavior of dielectric properties was explained on the basis of Maxwell-Wagner interfacial polarization which in accordance with Koops phenomenological theory. Real and imaginary part of impedance was studied as a function of resistance and Gd3+ substitution. The behavior of impedance is systematically discussed on the basis of resistance-capacitance circuit.

  16. Influence of Rare Earth (Gd3+) on Structural, Gigahertz Dielectric and Magnetic Studies of Cobalt ferrite

    NASA Astrophysics Data System (ADS)

    Pervaiz, Erum; Gul, I. H.

    2013-06-01

    A series of Gd3+ doped nanocrystalline Co-ferrites CoGdxFe2-xO4 (x = 0.0 to 0.1) has been prepared by sol-gel auto combustion technique. Structural and morphology studies were performed using X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). Indexed XRD patterns confirm the formation of pure cubic spinel phase. Average crystallite sizes ranges from 16 nm to 25 nm ±2, were calculated from Sherrer's formula and Williamson Hall plots. Crystal strain increases with increase in doping amount of trivalent Gd ion. Lattice constant (a) and crystallite size D (311) increases with increase in Gd3+ concentration due to large ionic radii (0.94nm) of Gd3+ replacing Fe3+ (0.64nm). SEM images show the spherical morphology and uniform size distribution. Room temperature DC electrical resistivity decreases (~106) for x=0.025 then increases up to x=0.1 ~ (4.5×107). Dielectric properties have been studied using RF Impedance/material analyzer in the frequency range of 1 MHz to 1GHz. All the studied samples show a semi-conducting behavior as Permittivity and tangent loss (tanδ) decreases with the substitution of Gd3+ in parent crystal structure and have values of 4.92 and 0.016 at 1 GHz respectively. Complex impedance and Complex electric modulus plots were further studied for complete contribution of grains and grain boundary resistances to conduction and resonance frequencies respectively. Magnetic studies by Vibrating Sample Magnetometer (VSM) shows that magnetization (Ms) decreases with increase in Gd3+ concentration from 63 emu/gm to 27.26 emu/gm. Coercivity (Hc) first decreases for x=0.025, after which it increases to 2308 Oe for x=0.1.

  17. Absorption Spectra and Energy Levels of Gd(3+), Nd(3+), and Cr(3+) in the Garnet Gd3Sc2Ga3O12.

    DTIC Science & Technology

    1988-03-01

    The doping of GSGG with neodymium and chromium is better controlled as compared with Y3AI50 2 ( YAG ), The dopant distribution is governed by the same...liquid helium temperature. z . . . . .. . . . . . . 3400 3;03 3 i00 - aF~i WAVE LIENG Tm A n18 e!4 Figure 8. Absorption spectrum ofL[6Pl7/21(A CBfl...Splitting Calculations: Nd 3+, Gd3 The material GSGG is a mixed garnet with the same crystal structure as Y3A150 12 ( YAG ) 121,221. The cubic space group is

  18. Ganglioside-magnetosome complex formation enhances uptake of gangliosides by cells

    PubMed Central

    Guan, Feng; Li, Xiang; Guo, Jia; Yang, Ganglong; Li, Xiang

    2015-01-01

    Bacterial magnetosomes, because of their nano-scale size, have a large surface-to-volume ratio and are able to carry large quantities of bioactive substances such as enzymes, antibodies, and genes. Gangliosides, a family of sialic acid-containing glycosphingolipids, function as distinctive cell surface markers and as specific determinants in cellular recognition and cell-to-cell communication. Exogenously added gangliosides are often used to study biological functions, transport mechanisms, and metabolism of their endogenous counterparts. Absorption of gangliosides into cells is typically limited by their tendency to aggregate into micelles in aqueous media. We describe here a simple strategy to remove proteins from the magnetosome membrane by sodium dodecyl sulfate treatment, and efficiently immobilize a ganglioside (GM1 or GM3) on the magnetosome by mild ultrasonic treatment. The maximum of 11.7±1.2 µg GM1 and 11.6±1.5 μg GM3 was loaded onto 1 mg magnetosome, respectively. Complexes of ganglioside-magnetosomes stored at 4°C for certain days presented the consistent stability. The use of GM1-magnetosome complex resulted in the greatest enhancement of ganglioside incorporation by cells. GM3-magnetosome complex significantly inhibited EGF-induced phosphorylation of the epidermal growth factor receptor. Both of these effects were further enhanced by the presence of a magnetic field. PMID:26609230

  19. The photoluminescence, drug delivery and imaging properties of multifunctional Eu3+/Gd3+ dual-doped hydroxyapatite nanorods.

    PubMed

    Chen, Feng; Huang, Peng; Zhu, Ying-Jie; Wu, Jin; Zhang, Chun-Lei; Cui, Da-Xiang

    2011-12-01

    The design and synthesis of multifunctional systems with high biocompatibility are very significant for the future of clinical applications. Herein, we report a microwave-assisted rapid synthesis of multifunctional Eu(3+)/Gd(3+) dual-doped hydroxyapatite (HAp) nanorods, and the photoluminescence (PL), drug delivery and in vivo imaging of as-prepared Eu(3+)/Gd(3+) doped HAp nanorods. The photoluminescent and magnetic multifunctions of HAp nanorods are realized by the dual-doping with Eu(3+) and Gd(3+). The PL intensity of doped HAp nanorods can be adjusted by varying Eu(3+) and Gd(3+) concentrations. The magnetization of doped HAp nanorods increases with the concentration of doped Gd(3+). The as-prepared Eu(3+)/Gd(3+)-doped HAp nanorods exhibit inappreciable toxicity to the cells in vitro. More importantly, the Eu(3+)/Gd(3+)-doped HAp nanorods show a high drug adsorption capacity and sustained drug release using ibuprofen as a model drug, and the drug release is governed by a diffusion process. Furthermore, the noninvasive visualization of nude mice with subcutaneous injection indicates that the Eu(3+)/Gd(3+)-doped HAp nanorods with the photoluminescent function are suitable for in vivo imaging. In vitro and in vivo imaging tests indicate that Eu(3+)/Gd(3+)-doped HAp nanorods have a potential in applications such as a multiple-model imaging agent for magnetic resonance (MR) imaging, photoluminescence imaging and computed tomography (CT) imaging. The Eu(3+)/Gd(3+) dual-doped HAp nanorods are promising for applications in the biomedical fields such as multifunctional drug delivery systems with imaging guidance.

  20. Enhanced MRI relaxivity of aquated Gd3+ ions by carboxyphenylated water-dispersed graphene nanoribbons.

    PubMed

    Gizzatov, Ayrat; Keshishian, Vazrik; Guven, Adem; Dimiev, Ayrat M; Qu, Feifei; Muthupillai, Raja; Decuzzi, Paolo; Bryant, Robert G; Tour, James M; Wilson, Lon J

    2014-03-21

    The present study demonstrates that highly water-dispersed graphene nanoribbons dispersed by carboxyphenylated substituents and conjugated to aquated Gd(3+) ions can serve as a high-performance contrast agent (CA) for applications in T1- and T2-weighted magnetic resonance imaging (MRI) with relaxivity (r1,2) values outperforming currently-available clinical CAs by up to 16 times for r1 and 21 times for r2.

  1. Persistent luminescence in powdered and ceramic polycrystalline Gd3Al2Ga3O12:Ce

    NASA Astrophysics Data System (ADS)

    Dosovitskiy, G.; Fedorov, A.; Mechinsky, V.; Borisevich, A.; Dosovitskiy, A.; Tret’jak, E.; Korjik, M.

    2017-02-01

    This paper studies powders of Gd3Ga3Al2O12:Ce, a promising scintillator composition, as a possible object for express pre-characterization of scintillation kinetics and level of persistent luminescence. Garnet phase powders with uniform microstructure, consisting of 1-2 μm grains, were obtained by co-precipitation approach. It was shown, that both scintillation decay time and presence of persistent luminescence are influenced by both powder thermal treatment temperature and strong Ga deficit.

  2. Structural and dielectric behavior of Cr3+ and Gd3+ substituted Ni-Zn nano ferrites

    NASA Astrophysics Data System (ADS)

    Anupama M., K.; Jagadeesha Angadi, V.; Matteppanavar, Shidaling; Pattar, Vinayak; Rudraswamy, B.

    2016-05-01

    A series of Gd3+ doped nano crystalline Ni0.6Zn0.4Cr0.5GdxFe1.5-xO4 (where x=0. 00, 0.02, 0.04, 0.06) were prepared by solution combustion method using oxalyl dehydrazide (ODH) as a fuel. The Structural and dielectric behavior of as synthesized material was characterized through X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR). XRD pattern reveals that the formation of single phase with cubic spinel structure. The average crystallite size and lattice parameter were found to increase with increasing Gd3+ concentration. The FTIR spectra shows two strong absorption bands at 387 cm-1 and 564 cm-1 both represents tetrahedral and octahedral stretching bonds respectively. The dielectric properties were carried out as a function of frequency and composition with the frequency range 40Hz to 10MHz. All the samples show the collective contribution of n-type and p-type carriers. The permittivity were found to decrease with increasing of Gd3+ concentration this is due to hopping off electrons and charge transport which is typical characteristic of polar dielectrics. Complex impedance was studied to know the contribution of grains and grain boundary resistance has explained according to the Maxwell Wagener type two layer model.

  3. Impact of Gd3+ doping and glassing solvent deuteration on 13C DNP at 5 Tesla

    NASA Astrophysics Data System (ADS)

    Kiswandhi, Andhika; Lama, Bimala; Niedbalski, Peter; Goderya, Mudrekh; Long, Joanna; Lumata, Lloyd

    Dynamic nuclear polarization (DNP) is a technique which can be used to amplify signals in nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) by several thousand-fold. The most commonly available DNP system typically operates at the W-band field or 3.35 T, at which it has been shown that 13C NMR signal can be enhanced by deuteration and Gd3+ doping. In this work, we have investigated the applicability of these procedures at 5 T. Our results indicate that the deuteration of the glassing matrix still yields an enhancement of 13C DNP when 4-oxo-TEMPO free radical is used. The effect is attributed to the lower heat load of the deuterons compared to protons. An addition of a trace amount of Gd3+ gives a modest enhancement of the signal when trityl OX063 is used, albeit with a less pronounced relative enhancement compared to the results obtained at 3.35 T. The results suggest that the enhancement obtained via Gd3+ doping may become saturated at higher field. These results will be discussed using a thermodynamic model of DNP. This work is supported by US Dept of Defense Award No. W81XWH-14-1-0048 and Robert A. Welch Foundation Grant No. AT-1877.

  4. Macrocyclic Gd(3+) complexes with pendant crown ethers designed for binding zwitterionic neurotransmitters.

    PubMed

    Oukhatar, Fatima; Meudal, Hervé; Landon, Céline; Logothetis, Nikos K; Platas-Iglesias, Carlos; Angelovski, Goran; Tóth, Éva

    2015-07-27

    A series of Gd(3+) complexes exhibiting a relaxometric response to zwitterionic amino acid neurotransmitters was synthesized. The design concept involves ditopic interactions 1) between a positively charged and coordinatively unsaturated Gd(3+) chelate and the carboxylate group of the neurotransmitters and 2) between an azacrown ether appended to the chelate and the amino group of the neurotransmitters. The chelates differ in the nature and length of the linker connecting the cyclen-type macrocycle that binds the Ln(3+) ion and the crown ether. The complexes are monohydrated, but they exhibit high proton relaxivities (up to 7.7 mM(-1)  s(-1) at 60 MHz, 310 K) due to slow molecular tumbling. The formation of ternary complexes with neurotransmitters was monitored by (1) H relaxometric titrations of the Gd(3+) complexes and by luminescence measurements on the Eu(3+) and Tb(3+) analogues at pH 7.4. The remarkable relaxivity decrease (≈80 %) observed on neurotransmitter binding is related to the decrease in the hydration number, as evidenced by luminescence lifetime measurements on the Eu(3+) complexes. These complexes show affinity for amino acid neurotransmitters in the millimolar range, which can be suited to imaging concentrations of synaptically released neurotransmitters. They display good selectivity over non-amino acid neurotransmitters (acetylcholine, serotonin, and noradrenaline) and hydrogenphosphate, but selectivity over hydrogencarbonate was not achieved.

  5. Postnatal dietary supplementation with either gangliosides or choline: effects on spatial short-term memory in artificially-reared rats.

    PubMed

    Wainwright, Patricia E; Lomanowska, Anna M; McCutcheon, Dawn; Park, Eek J; Clandinin, M Thomas; Ramanujam, Kalathur S

    2007-01-01

    This study addressed the hypothesis that dietary supplementation with either gangliosides or choline during the brain growth spurt would enhance short-term spatial memory. Male Long-Evans rats were reared artificially from postnatal days (PD) 5-18 and were fed diets containing either (i) choline chloride 1250 mg/l (CHL), (ii) choline chloride 250 mg/l and GD3 24 mg/l (GNG) or (iii) choline chloride 250 mg/l (STD). A fourth group (SCK) was reared normally. Rats were weaned onto AIN 93G diet and on PD 35 were trained on a cued delayed- matching-to-place version of the Morris water maze. All groups learned to swim to the beacon that indicated the platform position on the first trial; similarly, on the second un-cued trial, the distance swam to reach the platform decreased to the same extent in all groups over the five days of training. The groups also responded in the same way to an increase in delay between the first and second trial from 1 min to 1 h, showing an increase in the distance swam, accompanied by a decrease in the number of direct swims to the platform. Thus, all rats were equally proficient at using spatial short-term memory, regardless of the choline or ganglioside content of the preweaning diet.

  6. Inhibitory effect of ganglioside GD1b on K+ current in hippocampal neurons and its involvement in apoptosis suppression.

    PubMed

    Chen, Xuesong; Chi, Shaopeng; Liu, Mingna; Yang, Wei; Wei, Taotao; Qi, Zhi; Yang, Fuyu

    2005-12-01

    Gangliosides are endogenous membrane components enriched in neuronal cells. They have been shown to play regulatory roles in many cellular processes. Here, we show for the first time that ganglioside GD1b plays an antiapoptotic role in cultured hippocampal neurons. GD1b inhibited the voltage-dependent outward delayed rectifier current (I(K)) but not the transient outward A-type current in a dose-dependent manner, with an IC50 value of 15.2 microM. This effect appears to be somehow specific, because GD1b, but not GM1, GM2, GM3, GD1a, GD3, or GT1b, was effective in inhibiting I(K). Intracellular application of staurosporine (STS; 0.1 microM) resulted in rapid activation of I(K), which was partially reversed upon addition of the K+ channel blocker tetraethylammonium (TEA; 5 mM) and GD1b (10 microM). Furthermore, GD1b (10 microM) attenuated STS-induced neuronal apoptosis by nearly the same amount as 5 mM TEA. In addition, GD1b suppressed the apoptosis-associated caspase 3 activation that was activated by STS. Collectively, these findings suggest that GD1b plays an antiapoptotic role in cultured hippocampal neurons through its inhibitory effect on the I(K) and caspase activity.

  7. The Role of Gangliosides in Neurodevelopment

    PubMed Central

    Palmano, Kate; Rowan, Angela; Guillermo, Rozey; Guan, Jian; Mc Jarrow, Paul

    2015-01-01

    Gangliosides are important components of neuronal cell membranes and it is widely accepted that they play a critical role in neuronal and brain development. They are functionally involved in neurotransmission and are thought to support the formation and stabilization of functional synapses and neural circuits required as the structural basis of memory and learning. Available evidence, as reviewed herein, suggests that dietary gangliosides may impact positively on cognitive functions, particularly in the early postnatal period when the brain is still growing. Further, new evidence suggests that the mechanism of action may be through an effect on the neuroplasticity of the brain, mediated through enhanced synaptic plasticity in the hippocampus and nigro-striatal dopaminergic pathway. PMID:26007338

  8. The role of gangliosides in neurodevelopment.

    PubMed

    Palmano, Kate; Rowan, Angela; Guillermo, Rozey; Guan, Jian; McJarrow, Paul

    2015-05-22

    Gangliosides are important components of neuronal cell membranes and it is widely accepted that they play a critical role in neuronal and brain development. They are functionally involved in neurotransmission and are thought to support the formation and stabilization of functional synapses and neural circuits required as the structural basis of memory and learning. Available evidence, as reviewed herein, suggests that dietary gangliosides may impact positively on cognitive functions, particularly in the early postnatal period when the brain is still growing. Further, new evidence suggests that the mechanism of action may be through an effect on the neuroplasticity of the brain, mediated through enhanced synaptic plasticity in the hippocampus and nigro-striatal dopaminergic pathway.

  9. Brain gangliosides in the presenile dementia of Pick.

    PubMed Central

    Kamp, P E; den Hartog Jager, W A; Maathuis, J; de Groot, P A; de Jong, J M; Bolhuis, P A

    1986-01-01

    Histochemical analysis of frontal and temporal lobes from four patients with Pick presenile dementia indicated intracellular and extracellular deposits of gangliosides. Thin layer chromatography of gangliosides disclosed the presence of an unknown ganglioside, a decrease of N-acetylgalactosamine-GDla and an increase of GTla and/or GD2 in white matter of Pick brain. Chromatography of gray matter and quantitation of the sialic acid content yielded results similar to controls. It is suggested that degradation and removal of gangliosides is incomplete in Pick disease. Images PMID:3746324

  10. Investigation of Gd3N@C2n (40 <= n <= 44) family by Raman and inelastic electron tunneling spectroscopy

    NASA Astrophysics Data System (ADS)

    Burke, Brian; Chan, Jack; Williams, Keith; Ge, Jiechao; Shu, Chunying; Fu, Wujun; Dorn, Harry; Kushmerick, James; Puretzky, Alexander; Geohegan, David

    2010-03-01

    The structure and vibrational spectrum of Gd3N@C80 is studied through Raman and inelastic electron tunneling spectroscopy (IETS) as well as density functional theory (DFT) and universal force field (UFF) calculations. Hindered rotations, shown by both theory and experiment, indicate the formation of a Gd3N-C80 bond which reduces the ideal icosahedral symmetry of the C80 cage. The vibrational modes involving the movement of the encapsulated species are a fingerprint of the interaction between the fullerene cage and the core complex. We present Raman data for the Gd3N@C2n (40 <= n <= 44) family as well as Y3N@C80, Lu3N@C80, and Y3N@C88 for comparison. Conductance measurements have been performed on Gd3N@C80 and reveal a Kondo effect similar to that observed in C60.

  11. Recombination luminescence of CaSO4:Tb3+ and CaSO4:Gd3+phosphors

    NASA Astrophysics Data System (ADS)

    Kudryavtseva, Irina; Lushchik, Aleksandr; Maaroos, Aarne; Azmaganbetova, Zhannur; Nurakhmetov, Turlybek; Salikhoja, Zhussupbek

    2012-08-01

    A comparative study of the excitation of luminescence by VUV radiation as well as of thermally and photostimulated luminescence has been carried out for CaSO4:Tb3+ and CaSO4:Gd3+ phosphors, where Na+ or F- ions are used for charge compensation. The distinction in hole processes for the phosphors with Na+ or F- compensators is determined by the differing thermal stability of the holes localized at/near Tb3+Na+ and Gd3+Na+ (up to 100-160 K) or at/near Tb3+F- V Ca and Gd3+F- V Ca centers involving also a cation vacancy (up to 400-550 K). Tunnel luminescence in the pairs of localized electrons and holes nearby Tb3+ or Gd3+ has been detected. The mechanisms of electron-hole, hole-electron and tunnel recombination luminescence as well as a subsequent released energy transfer to RE3+ ions are considered.

  12. Zero field splitting fluctuations induced phase relaxation of Gd3+ in frozen solutions at cryogenic temperatures

    PubMed Central

    Raitsimring, A.; Dalaloyan, A.; Collauto, A.; Feintuch, A.; Meade, T.; Goldfarb, D.

    2015-01-01

    Distance measurements using double electron–electron resonance (DEER) and Gd3+ chelates for spin labels (GdSL) have been shown to be an attractive alternative to nitroxide spin labels at W-band (95 GHz). The maximal distance that can be accessed by DEER measurements and the sensitivity of such measurements strongly depends on the phase relaxation of Gd3+ chelates in frozen, glassy solutions. In this work, we explore the phase relaxation of Gd3+-DOTA as a representative of GdSL in temperature and concentration ranges typically used for W-band DEER measurements. We observed that in addition to the usual mechanisms of phase relaxation known for nitroxide based spin labels, GdSL are subjected to an additional phase relaxation mechanism that features an increase in the relaxation rate from the center to the periphery of the EPR spectrum. Since the EPR spectrum of GdSL is the sum of subspectra of the individual EPR transitions, we attribute this field dependence to transition dependent phase relaxation. Using simulations of the EPR spectra and its decomposition into the individual transition subspectra, we isolated the phase relaxation of each transition and found that its rate increases with |ms|. We suggest that this mechanism is due to transient zero field splitting (tZFS), where its magnitude and correlation time are scaled down and distributed as compared with similar situations in liquids. This tZFS induced phase relaxation mechanism becomes dominant (or at least significant) when all other well-known phase relaxation mechanisms, such as spectral diffusion caused by nuclear spin diffusion, instantaneous and electron spin spectral diffusion, are significantly suppressed by matrix deuteration and low concentration, and when the temperature is sufficiently low to disable spin lattice interaction as a source of phase relaxation. PMID:25442776

  13. Zero field splitting fluctuations induced phase relaxation of Gd3+ in frozen solutions at cryogenic temperatures

    NASA Astrophysics Data System (ADS)

    Raitsimring, A.; Dalaloyan, A.; Collauto, A.; Feintuch, A.; Meade, T.; Goldfarb, D.

    2014-11-01

    Distance measurements using double electron-electron resonance (DEER) and Gd3+ chelates for spin labels (GdSL) have been shown to be an attractive alternative to nitroxide spin labels at W-band (95 GHz). The maximal distance that can be accessed by DEER measurements and the sensitivity of such measurements strongly depends on the phase relaxation of Gd3+ chelates in frozen, glassy solutions. In this work, we explore the phase relaxation of Gd3+-DOTA as a representative of GdSL in temperature and concentration ranges typically used for W-band DEER measurements. We observed that in addition to the usual mechanisms of phase relaxation known for nitroxide based spin labels, GdSL are subjected to an additional phase relaxation mechanism that features an increase in the relaxation rate from the center to the periphery of the EPR spectrum. Since the EPR spectrum of GdSL is the sum of subspectra of the individual EPR transitions, we attribute this field dependence to transition dependent phase relaxation. Using simulations of the EPR spectra and its decomposition into the individual transition subspectra, we isolated the phase relaxation of each transition and found that its rate increases with |ms|. We suggest that this mechanism is due to transient zero field splitting (tZFS), where its magnitude and correlation time are scaled down and distributed as compared with similar situations in liquids. This tZFS induced phase relaxation mechanism becomes dominant (or at least significant) when all other well-known phase relaxation mechanisms, such as spectral diffusion caused by nuclear spin diffusion, instantaneous and electron spin spectral diffusion, are significantly suppressed by matrix deuteration and low concentration, and when the temperature is sufficiently low to disable spin lattice interaction as a source of phase relaxation.

  14. Gangliosides in the Nervous System: Biosynthesis and Degradation

    NASA Astrophysics Data System (ADS)

    Yu, Robert K.; Ariga, Toshio; Yanagisawa, Makoto; Zeng, Guichao

    Gangliosides, abundant in the nervous system, are known to play crucial modulatory roles in cellular recognition, interaction, adhesion, and signal transduction, particularly during early developmental stages. The expression of gangliosides in the nervous system is developmentally regulated and is closely related to the differentiation state of the cell. Ganglioside biosynthesis occurs in intracellular organelles, from which gangliosides are transported to the plasma membrane. During brain development, the ganglioside composition of the nervous system undergoes remarkable changes and is strictly regulated by the activities of glycosyltransferases, which can occur at different levels of control, including glycosyltransferase gene transcription and posttranslational modification. Genes for glycosyltransferase involved in ganglioside biosynthesis have been cloned and classified into families of glycosyltransferases based on their amino acid sequence similarities. The donor and acceptor substrate specificities are determined by enzymatic analysis of the glycosyltransferase gene products. Cell-type specific regulation of these genes has also been studied. Gangliosides are degraded by lysosomal exoglycosidases. The action of these enzymes occurs frequently in cooperation with activator proteins. Several human diseases are caused by defects of degradative enzymes, resulting in massive accumulation of certain glycolipids, including gangliosides in the lysosomal compartment and other organelles in the brain and visceral organs. Some of the representative lysosomal storage diseases (LSDs) caused by the accumulation of lipids in late endosomes and lysosomes will be discussed.

  15. Structural and dc electrical resistivity study of Gd 3+-substituted Cu-Cd mixed ferrites

    NASA Astrophysics Data System (ADS)

    Kolekar, C. B.; Kamble, P. N.; Vaingankar, A. S.

    1994-11-01

    Polycrystalline ferrite compositions of Cd xCu 1- xFe 2- yGd yO 4 ( x = 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0; y = 0.0 and 0.1) were prepared by the standard ceramic technique. The X-ray crystallographic study was done using filtered Cu K α radiation. From the diffractograms it is observed that for x ⩾ 0.2 compounds are cubic spinels, while for x = 0 they are tetragonal, and the dependence of the lattice constant on cadmium concentration obeys Vegard's law. The infrared absorption of the powder samples shows two strong absorption bands in the frequency range 400-600 cm -1, and the analysis shows that Gd occupies 'B' sites. The chemical analysis was done by atomic absorption spectroscopy. The dc resistivity study shows an increase in Δ E values and thus in the resistivity after Gd 3+ substitution, suggesting that even though Gd 3+ occupies 'B' sites it does not take part in the conduction mechanism, but impedes it.

  16. Influence of Gd3+ concentration on luminescence properties of Eu3+ ions in sol-gel materials

    NASA Astrophysics Data System (ADS)

    Szpikowska-Sroka, Barbara; Pawlik, Natalia; Pisarski, Wojciech A.

    2016-12-01

    The sol-gel powders doubly-doped with Gd3+/Eu3+ ions with different concentration of Gd3+ have been successfully obtained. The spectroscopic characterization of prepared samples was conducted based on excitation and emission spectra as well as luminescence decay analysis. Upon direct excitation of Eu3+ active ions, the characteristic 5D0 → 7F1 (orange) and 5D0 → 7F2 (red) emission bands were observed. The energy transfer from Gd3+ to Eu3+ ions was registered upon λexc = 273 nm excitation. An efficient conversion of ultraviolet radiation (UV) into visible luminescence was successfully observed. The energy transfer process from Gd3+ to Eu3+ led to longer luminescence decay from the 5D0 state in comparison to that obtained under direct excitation of Eu3+ ions (λexc = 393 nm). Generally, obtained results clearly indicated the beneficial influence of increasing concentration of Gd3+ ions on luminescence properties of Eu3+ in studied silica sol-gel phosphors.

  17. Temperature-stabilized optical isolator for collimated light using (BiLuGd)(3)Fe(5)O(12)/(BiGd)(3)(FeGa)(5)O(12) composite film.

    PubMed

    Matsuda, K; Mlnernoto, H; Kamada, O; Ishlzuka, S

    1988-04-01

    We have fabricated optical isolators whose temperature dependence of the isolation ratio has a stability of <0.2 dB using (BiLuGd)(3)Fe(5)O(12)/(BiGd)(3)(FeGa)(5)0(12) composite film. It has been confirmed that the temperature-dependent forward loss of the isolators originates from the thermal fluctuation of the absorption peak in the films. We have also evaluated the degradation of the isolation ratio for collimated light depending on the incident angle of the collimated light, the incident position with respect to the optic axis, and the wavelength range needed for practical use.

  18. NIR to VUV: Seven-Photon Upconversion Emissions from Gd(3+) Ions in Fluoride Nanocrystals.

    PubMed

    Zheng, Kezhi; Qin, Weiping; Cao, Chunyan; Zhao, Dan; Wang, Lili

    2015-02-05

    Here we show that a near-infrared (NIR) diode laser is capable of generating vacuum ultraviolet (VUV) emissions in fluoride nanocrystals through photon upconversion (UC) processes. By using Yb(3+) and Tm(3+) as sensitizers, we successfully obtained the VUV photons with the energy exceeding 6 eV in YF3: Yb, Tm, and Gd nanocrystals. The seven photon UC fluorescence from the (6)GJ → (8)S7/2 transitions of Gd(3+) ions and the possible VUV UC mechanism were reported along with the calculation of the branching ratio under different pumping power excitation. Practically, it offers a promising solution for VUV light generation without cryogens and expensive instrumentations. Fundamentally, the extremely high-order UC processes will intrigue great interest in exploring unusual high-energy radiative transitions in rare earth ions.

  19. Mapping of second-nearest-neighbor fluoride ions of orthorhombic Gd 3+-Ag + complexes in CaF 2

    NASA Astrophysics Data System (ADS)

    Nakata, R.; Den Hartog, H. W.

    The ENDOR technique is applied to determine the positions of 24 second-nearest-neighbor F - ions around an orthorhombic Gd 3+-Ag + complex in CaF 2 crystals. Experimental ENDOR data of the second-nearest-neighbor F - ions are analyzed by using the usual spin Hamiltonian and a least-squares fitting method. The best fits of the experimental results give superhyperfine (shf) constants and the F - directions ( K, L, M) with respect to the Gd 3+ ion, from which the distance between the second-nearest-neighbor F - ion and the Gd 3+ ion is determined by assuming that the hyperfine interaction is due to the classical dipole-dipole interaction. The displacements of the F - ions are estimated and compared with the theoretical values calculated by Bijvank and den Hartog on the basis of a polarizable point charge model.

  20. Enhanced relaxivity of Gd3+-based contrast agents geometrically confined within porous nanoconstructs

    PubMed Central

    Sethi, Richa; Ananta, Jeyarama S.; Karmonik, Christof; Zhong, Meng; Fung, Steve H.; Liu, Xuewu; Li, King; Ferrari, Mauro; Wilson, Lon J.; Decuzzi, Paolo

    2013-01-01

    Gadolinium chelates, which are currently approved for clinical MRI use, provide relaxivities well below their theoretical limit, and they also lack tissue specificity. Recently, the geometrical confinement of Gd3+-based contrast agents (CAs) within porous structures has been proposed as a novel, alternative strategy to improve relaxivity without chemical modification of the CA. Here, we have characterized and optimized the performance of MRI nanoconstructs obtained by loading [Gd(DTPA)(H2O)]2− (Magnevist®) into the pores of injectable mesoporous silicon particles. Nanoconstructs with three different pore sizes were studied, and at 60 MHz, they exhibited longitudinal relaxivities of ~ 24 mM−1s−1 for 5 – 10 nm pores and ~ 10 mM−1s−1 for 30 – 40 nm pores. No enhancement in relaxivity was observed for larger pores sizes. Using an outer-sphere compound, [GdTTHA]−3, and mathematical modeling, it was demonstrated that the relaxivity enhancement is due to the increase in rotational correlation times (CA adsorbed on the pore walls) and diffusion correlation times (reduced mobility of the water molecules), as the pore sizes decreases. It was also observed that extensive CA adsorption on the outer surface of the silicon particles negates the advantages offered by nanoscale confinement. Upon incubation with HeLa cells, the nanoconstructs did not demonstrate significant cytotoxicity for up to 3 days post incubation, at different particle/cell ratios. In addition, the nanoconstructs showed complete degradation after 24h of continuous agitation in PBS. These data support and confirm the hypothesis that the geometrical confinement of Gd3+-chelate compounds into porous structures offers MRI nanoconstructs with enhanced relaxivity (up to 6 times for [Gd(DTPA)(H2O)]2−, and 4 times for [GdTTHA]−3) and, potentially, improved stability, reduced toxicity and tissue specificity. PMID:22991316

  1. Effect of Gd3+ substitution on structural, magnetic, dielectric and optical properties of nanocrystalline CoFe2O4

    NASA Astrophysics Data System (ADS)

    Joshi, Seema; Kumar, Manoj; Chhoker, Sandeep; Kumar, Arun; Singh, Mahavir

    2017-03-01

    Nanoparticles of CoGdxFe2-xO4 with x=0.0, 0.03, 0.05, 0.07, 0.10 and 0.15 were synthesized by co-precipitation method. Gd3+ substitution effect on different properties of nanocrystalline CoFe2O4 has been studied. X-ray diffraction and Raman spectroscopy confirmed the formation of single phase cubic mixed spinel structure. Cation distribution has been proposed from Rietveld refined data. Mössbauer spectra at room temperature showed two ferrimagnetic Zeeman sextets with one superparamagnetic doublet. Mössbauer parameters suggested that Gd3+ ions occupy the octahedral site in CoFe2O4. Room temperature magnetic measurements exhibited that the saturation magnetization decreased from 91 emu/gm to 54 emu/gm for x=0.0 to 0.15 samples. The coercivity decreased from 1120 Oe to 340 Oe for x=0.0 to 0.07 samples and increased from 400 Oe to 590 Oe for x=0.10 and 0.15 samples, respectively. Raman analysis showed that the degree of inversion with Gd3+ substitution supporting the variation of coercivity. Electron spin resonance spectra revealed the dominancy of superexchange interactions in these samples. Optical band gap measurement suggested that all samples are indirect band gap materials and band gap has been decreased with Gd3+ substitution. Both dielectric constant and dielectric loss is found to decrease because of the decrease in hopping rate with the Gd3+ substitution for Fe3+ at the octahedral sites. Low dielectric loss suggested the applicability of Gd3+ doped CoFe2O4 nanoparticles for high frequency microwave device applications.

  2. Coupling fast water exchange to slow molecular tumbling in Gd3+ chelates: why faster is not always better

    PubMed Central

    Avedano, Stefano; Botta, Mauro; Haigh, Julian S.; Longo, Dario; Woods, Mark

    2013-01-01

    The influence of dynamics on solution state structure is a widely overlooked consideration in chemistry. Variations in Gd3+ chelate hydration with changing coordination geometry and dissociative water exchange kinetics substantially impact the effectiveness (or relaxivity) of mono-hydrated Gd3+ chelates as T1-shortening contrast agents for MRI. Theory shows that relaxivity is highly dependent upon the Gd3+-water proton distance (rGdH) and yet this distance is almost never considered as a variable in assessing the relaxivity of a Gd3+ chelate as a potential contrast agent. The consequence of this omission can be seen when considering the relaxivity of isomeric Gd3+ chelates that exhibit different dissociative water exchange kinetics. The results described herein show that the relaxivity of a chelate with ‘optimal’ dissociative water exchange kinetics is actually lower than that of an isomeric chelate with ‘sub-optimal’ dissociative water exchange. When the rate of molecular tumbling of these chelates is slowed, an approach that has long been understood to increase relaxivity, the observed difference in relaxivity is increased with the more rapidly exchanging (‘optimal’) chelate exhibiting lower relaxivity than the ‘sub-optimally’ exchanging isomer. The difference between the chelates arises from a non-field dependent parameter: either the hydration number (q) or rGdH. For solution state Gd3+ chelates, changes in the values of q and rGdH are indistinguishable. These parametric expressions simply describe the hydration state of the chelate – i.e. the number and position of closely associating water molecules. The hydration state (q/rGdH6) of a chelate is intrinsically linked to its dissociative water exchange rate kex and the interrelation of these parameters must be considered when examining the relaxivity of Gd3+ chelates. The data presented herein indicates that the changes in the hydration parameter (q/rGdH6) associated with changing dissociative

  3. Mode of interaction of ganglioside Langmuir monolayer originated from echinoderms: three binary systems of ganglioside/DPPC, ganglioside/DMPE, and ganglioside/cholesterol.

    PubMed

    Hoda, Kazuki; Ikeda, Yuriko; Kawasaki, Hideya; Yamada, Koji; Higuchi, Ryuichi; Shibata, Osamu

    2006-09-01

    The surface pressure (pi)-area (A), the surface potential (DeltaV)-A, and the dipole moment (mu( perpendicular))-A isotherms were obtained for monolayers made from a ganglioside originated from echinoderms [Diadema setosum ganglioside (DSG-1)], dipalmitoylphosphatidylcholine (DPPC), dimyristoylphosphatidylethanolamine (DMPE), cholesterol (Ch), and their combinations. Monolayers spread on several different substrates were investigated at the air/water interface by the Wilhelmy method, ionizing electrode method, fluorescence microscopy (FM) and atomic force microscopy (AFM). Surface potentials (DeltaV) of pure components were analyzed using the three-layer model proposed by Demchak and Fort [R.J. Demchak, T. Fort, J. Colloid Interface Sci. 46 (1974) 191-202]. The new finding was that DSG-1 was stable and showed a liquid-expanded film and that its monolayer behavior of DeltaV was sensitive for the change of the NaCl concentration in the subphase. Moreover, the miscibility of DSG-1 and three major lipids in the two-component monolayers was examined by plotting the variation of the molecular area and the surface potential as a function of the DSG-1 molar fraction (X(DSG-1)), using the additivity rule. From the A-X(DSG-1) and DeltaV(m)-X(DSG-1) plots, partial molecular surface area (PMA) and apparent partial molecular surface potential (APSP) were determined at the discrete surface pressure. The PMA and APSP with the mole fraction were extensively discussed for the miscible system. The miscibility was also investigated from the two-dimensional phase diagrams. Furthermore, a regular surface mixture, for which the Joos equation was used for the analysis of the collapse pressure of two-component monolayers, allowed calculation of the interaction parameter (xi) and the interaction energy (-Deltavarepsilon) between them. The observations using fluorescence microscopy and AFM image also provide us the miscibility in the monolayer state.

  4. The sites of Gd3 + in the luminescent matrix La1 - xGdxMgAl11O19: Single crystal structure determination and site-selective excitation of Gd3 +

    NASA Astrophysics Data System (ADS)

    Salem, Y.; Linares, C.; Jacquier, B.; Saine, M. C.; Gasperin, M.; Lejus, A. M.; Vivien, D.

    1990-11-01

    Single crystals of La1-xGdxMgAl11O19 for x=0.02 to 1 have been grown from the melt by the Verneuil (flame fusion) method. The localization of Gd3+ ions in the matrix has been obtained using x-ray diffraction and Gd3+ fluorescence techniques giving the average and the local structure of the material. The resolution of the crystal structure, of La0.4Gd0.6MgAl11O19 homolog, indicates that this compound is of the distorted magnetoplumbite (MP) type (hexagonal P63/ mmc). Lanthanide ions lie in the mirror plane in two kinds of sites: the (2d) regular MP one (D3h symmetry) occupied by La3+ ions, the distorted (12j) one (Cs symmetry) partially filled up and containing only Gd3+. Some oxygen ions of the Ln coordination polyhedron may be missing leading to a lowering of the true symmetry of the sites. Site selective excitation of the fluorescence of Gd3+ and emission spectra have been carried out on crystals with different x values. It indicates that Gd3+ ions are distributed mainly among two sites, A and B. Crystal field analysis of the splitting of the 6P terms of Gd3+ determined on the excitation spectra show that site A is close to the ideal D3h symmetry while site B is a strongly distorted site. This leads to the identification A=(2d), B=(12j). The occupancy is larger for site B than for site A in agreement with the refinement of the structure. Selective laser excitation into the A site induces emission of the B sites as a result of energy transfer which is demonstrated by the fluorescence decay. No evidence of energy migration is found for gadolinium content up to 100%. Fluorescence spectroscopy and crystal structure determination appear complementary to obtain a detailed description of the sites of Gd3+ in La1-xGdxMgAl11O19.

  5. Biosynthesis and transport of gangliosides in peripheral nerve

    SciTech Connect

    Yates, A.J.; Tipnis, U.R.; Hofteig, J.H.; Warner, J.K.

    1984-01-01

    Radiolabelled glucosamine was injected into L-7 dorsal root ganglion (DRG) of rabbits. At several different times after injection DRG, lumbosacral trunks (LST) and sciatic nerves (SN) were removed and gangliosides extracted. Two and 3 weeks after injection the amounts of radioactivity in the ganglioside fractions of LST and SN were significantly higher than at days 1 and 2. The TCA soluble radioactivity decreased dramatically over the same time period. Colchicine prevented the appearance of radiolabelled lipid in LST and SN. From these experiments the authors conclude that some ganglioside is synthesized in the neuronal cell bodies of DRG and transported in the axons of the sciatic nerve. In another experiment the sciatic nerve was transected and ends separated to prevent regeneration. There was no difference in the amount of radiolabelled ganglioside that was isolated from DRG or LST of transected nerves compared with control nerves. The behavior of several potential acid soluble contaminants was studied in several steps used to isolate gangliosides. Of those studied only CMP-NeuAc could cause significant contamination of the final ganglioside preparation.

  6. Magnetooptics of the luminescent transitions in Tb3+:Gd3Ga5O12

    NASA Astrophysics Data System (ADS)

    Valiev, Uygun V.; Gruber, John B.; Ivanov, Igor'A.; Burdick, Gary W.; Liang, Hongbin; Zhou, Lei; Fu, Dejun; Pelenovich, Oleg V.; Pelenovich, Vasiliy O.; Lin, Zhou

    2015-08-01

    The spectra of the luminescence and magnetic circular polarization of luminescence in terbium-gadolinium gallium garnet Tb3+:Gd3Ga5O12 (Tb3+:GGG) were studied within the visible spectral range at temperatures T = 90 and 300 K in an external magnetic field of 0.45 T. The Zeeman effect in the luminescence "green" band associated with 4f → 4f transition 5D4 → 7F5 of Tb3+:GGG was also studied at T = 90 K in an external field of 0.55 T. Measurement of the Zeeman effect in Tb3+:GGG carried out for some doublet lines of the luminescence band 5D4 → 7F5 at T = 90 K shows that a magnetooptical effect of the intensity change of the emitted light is observed on these lines, in contrast to pure Zeeman splitting of the emission lines measured in the luminescence band 5D4 → 7F6. For the systems we have studied, the maximal value of the magnetooptical effect of the intensity change of the luminescence line at low temperatures has been achieved in paramagnetic garnet Tb0.2Y2.8Al5O12 at comparatively low magnetic fields.

  7. Surfactant-free Gd3+-ion-containing carbon nanotube MRI contrast agents for stem cell labeling

    NASA Astrophysics Data System (ADS)

    Gizzatov, Ayrat; Hernández-Rivera, Mayra; Keshishian, Vazrik; Mackeyev, Yuri; Law, Justin J.; Guven, Adem; Sethi, Richa; Qu, Feifei; Muthupillai, Raja; Cabreira-Hansen, Maria Da Graça; Willerson, James T.; Perin, Emerson C.; Ma, Qing; Bryant, Robert G.; Wilson, Lon J.

    2015-07-01

    There is an ever increasing interest in developing new stem cell therapies. However, imaging and tracking stem cells in vivo after transplantation remains a serious challenge. In this work, we report new, functionalized and high-performance Gd3+-ion-containing ultra-short carbon nanotube (US-tube) MRI contrast agent (CA) materials which are highly-water-dispersible (ca. 35 mg ml-1) without the need of a surfactant. The new materials have extremely high T1-weighted relaxivities of 90 (mM s)-1 per Gd3+ ion at 1.5 T at room temperature and have been used to safely label porcine bone-marrow-derived mesenchymal stem cells for MR imaging. The labeled cells display excellent image contrast in phantom imaging experiments, and TEM images of the labeled cells, in general, reveal small clusters of the CA material located within the cytoplasm with 109 Gd3+ ions per cell.There is an ever increasing interest in developing new stem cell therapies. However, imaging and tracking stem cells in vivo after transplantation remains a serious challenge. In this work, we report new, functionalized and high-performance Gd3+-ion-containing ultra-short carbon nanotube (US-tube) MRI contrast agent (CA) materials which are highly-water-dispersible (ca. 35 mg ml-1) without the need of a surfactant. The new materials have extremely high T1-weighted relaxivities of 90 (mM s)-1 per Gd3+ ion at 1.5 T at room temperature and have been used to safely label porcine bone-marrow-derived mesenchymal stem cells for MR imaging. The labeled cells display excellent image contrast in phantom imaging experiments, and TEM images of the labeled cells, in general, reveal small clusters of the CA material located within the cytoplasm with 109 Gd3+ ions per cell. Electronic supplementary information (ESI) available: NMRD profiles, the Fourier transforms of the EXAFS data, EXAFS curve fitting data, cell viability data. See DOI: 10.1039/c5nr02078f

  8. Electrical and electromechanical studies in ferroelectric Gd3+ modified lead potassium niobate ceramics

    NASA Astrophysics Data System (ADS)

    Sambasiva Rao, K.; Krishna, P. Murali; Dasari, Madhava P.; Lee, J. H.

    2011-08-01

    The change in dielectric constant relaxation time over temperature (35-590 °C) and frequency (45 Hz-5 MHz) in ceramics of Pb0.77K0.115Gd0.115Nb2O6 (PKGN, Tc = 340 °c) has been studied. Powder X-ray diffraction revealed the single-phase formation with orthorhombic crystal structure. The P-E hysteresis loop parameters are Ps = 21.77 μC/cm2, Pr = 17.09 μC/cm2, Ec = 11.86 kV/cm; the piezoelectric constants, Kp = 31.7%, Kt = 47%, d33 = 115 × 10-12 C/N, d31 = -41 × 10-12 C/N, are determined in the material and some transducer applications are discussed. Cole-Cole (Zll vs. Zl) plots showed a non-Debye type relaxation. Conductivity obeyed Jonscher's universal power law, σ = σ0 + Aωn. The theoretical values of ɛl and σ are computed using the parameters `A(T)' and `n(T)' (0 < n < 1) and are well fitted with the experimental data. The hopping ion frequency (ωp) and charge carrier concentration (Kl) have been analyzed using Almond-West formalism. The dielectric relaxation processes are associated with localized oxygen vacancies conduction at high frequency region. A long-range conductivity by Gd3+ ions is found to be predominant at low frequency region. The activation energies from impedance and modulus formalisms revealed the ionic type conduction in PKGN.

  9. Controlling the Two-Photon-Induced Photon Cascade Emission in a Gd3+/Tb3+-Codoped Glass for Multicolor Display

    PubMed Central

    Yuan, Mao-Hui; Fan, Hai-Hua; Li, Hui; Lan, Sheng; Tie, Shao-Long; Yang, Zhong-Min

    2016-01-01

    We reported the first observation of the two-photon-induced quantum cutting phenomenon in a Gd3+/Tb3+-codoped glass in which two photons at ~400 nm are simultaneously absorbed, leading to the cascade emission of three photons in the visible spectral region. The two-photon absorption induced by femtosecond laser pulses allows the excitation of the energy states in Gd3+ which are inactive for single-photon excitation and enables the observation of many new electric transitions which are invisible in the single-photon-induced luminescence. The competition between the two-photon-induced photon cascade emission and the single-photon-induced emission was manipulated to control the luminescence color of the glass. We demonstrated the change of the luminescence color from red to yellow and eventually to green by varying either the excitation wavelength or the excitation power density. PMID:26899189

  10. Recent progress in advanced optical materials based on gadolinium aluminate garnet (Gd3Al5O12)

    PubMed Central

    Li, Ji-Guang; Sakka, Yoshio

    2015-01-01

    This review article summarizes the recent achievements in stabilization of the metastable lattice of gadolinium aluminate garnet (Gd3Al5O12, GAG) and the related developments of advanced optical materials, including down-conversion phosphors, up-conversion phosphors, transparent ceramics, and single crystals. Whenever possible, the materials are compared with their better known YAG and LuAG counterparts to demonstrate the merits of the GAG host. It is shown that novel emission features and significantly improved luminescence can be attained for a number of phosphor systems with the more covalent GAG lattice and the efficient energy transfer from Gd3+ to the activator. Ce3+ doped GAG-based single crystals and transparent ceramics are also shown to simultaneously possess the advantages of high theoretical density, fast scintillation decay, and high light yields, and hold great potential as scintillators for a wide range of applications. The unresolved issues are also pointed out. PMID:27877750

  11. Recent progress in advanced optical materials based on gadolinium aluminate garnet (Gd3Al5O12).

    PubMed

    Li, Ji-Guang; Sakka, Yoshio

    2015-02-01

    This review article summarizes the recent achievements in stabilization of the metastable lattice of gadolinium aluminate garnet (Gd3Al5O12, GAG) and the related developments of advanced optical materials, including down-conversion phosphors, up-conversion phosphors, transparent ceramics, and single crystals. Whenever possible, the materials are compared with their better known YAG and LuAG counterparts to demonstrate the merits of the GAG host. It is shown that novel emission features and significantly improved luminescence can be attained for a number of phosphor systems with the more covalent GAG lattice and the efficient energy transfer from Gd(3+) to the activator. Ce(3+) doped GAG-based single crystals and transparent ceramics are also shown to simultaneously possess the advantages of high theoretical density, fast scintillation decay, and high light yields, and hold great potential as scintillators for a wide range of applications. The unresolved issues are also pointed out.

  12. Depletion of Gangliosides Enhances Articular Cartilage Repair in Mice

    PubMed Central

    Matsuoka, Masatake; Onodera, Tomohiro; Homan, Kentaro; Sasazawa, Fumio; Furukawa, Jun-ichi; Momma, Daisuke; Baba, Rikiya; Hontani, Kazutoshi; Joutoku, Zenta; Matsubara, Shinji; Yamashita, Tadashi; Iwasaki, Norimasa

    2017-01-01

    Elucidation of the healing mechanisms in damaged tissues is a critical step for establishing breakthroughs in tissue engineering. Articular cartilage is clinically one of the most successful tissues to be repaired with regenerative medicine because of its homogeneous extracellular matrix and few cell types. However, we only poorly understand cartilage repair mechanisms, and hence, regenerated cartilage remains inferior to the native tissues. Here, we show that glycosylation is an important process for hypertrophic differentiation during articular cartilage repair. GM3, which is a precursor molecule for most gangliosides, was transiently expressed in surrounding damaged tissue, and depletion of GM3 synthase enhanced cartilage repair. Gangliosides also regulated chondrocyte hypertrophy via the Indian hedgehog pathway. These results identify a novel mechanism of cartilage healing through chondrocyte hypertrophy that is regulated by glycosylation. Manipulation of gangliosides and their synthases may have beneficial effects on articular cartilage repair. PMID:28252046

  13. Effect of Gd3+- Cr3+ ion substitution on the structural, electrical and magnetic properties of Ni - Zn ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Anupama, M. K.; Rudraswamy, B.

    2016-09-01

    Gd3+ doped nickel zinc nanoceramics with general formula Ni0.4Zn0.6Cr0.5GdxFe1.5 - xO4 (where x=0.00, 0.02, 0.04, 0.06) were synthesized by solution combustion method using oxylyldehydrazine as a fuel. The obtained powder was sintered at 1000°C for 2h. The detailed structural, electrical and magnetic studies were carried out through X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), impedance spectroscopy and vibrating sample magnetometer (VSM). The XRD pattern of as prepared sample confirms the formation of single phase with cubic spinel structure. The average crystallite size was found to be 34 to 19 nm and decreases with increasing Gd3+ ion concentration. The IR spectra exhibited two expected absorption bands between 600 to 300 cm-1 corresponding to the stretching vibrations of tetrahedral (A) and octahedral (B) metal oxygen vibrations. The variation of room temperature real (ε') and imaginary (ε") part of dielectric permittivity as a function of frequency and composition have been studied in the frequency range from 40Hz to 10MHz. The real and imaginary dielectric permittivity decreases with increase in frequency as well as Gd3+ concentration, which is normal behaviour of ferrite material and results have been explained on the basis of Maxwell - Wagner's two layer model. The VSM results showed that the Gd3+ concentration had significant impact on the saturation magnetization and coercivity, x = 0.02 shows the highest value of dielectric constant and saturation magnetization, thus the material is becoming low loss dielectric and highly resistive and soft magnetic material due to Gd-Cr doping.

  14. Spin transition in Gd3N@C80, detected by low-temperature on-chip SQUID technique

    NASA Astrophysics Data System (ADS)

    Chen, L.; Carpenter, E. E.; Hellberg, C. S.; Dorn, H. C.; Shultz, M.; Wernsdorfer, W.; Chiorescu, I.

    2011-04-01

    We present a magnetic study of the Gd3N@C80 molecule, consisting of a Gd-trimer via a nitrogen atom, encapsulated in a C80 cage. This molecular system can be an efficient contrast agent for magnetic resonance imaging (MRI) applications. We used a low-temperature technique able to detect small magnetic signals by placing the sample in the vicinity of an on-chip SQUID. The technique implemented at the National High Magnetic Field Laboratory has the particularity of being able to operate in high magnetic fields of up to 7 T. The Gd3N@C80 shows a paramagnetic behavior and we find a spin transition of the Gd3N structure at 1.2 K. We perform quantum mechanical simulations, which indicate that one of the Gd ions changes from a 8S7/2 state (L = 0, S = 7/2) to a 7F6 state (L = S = 3, J = 6), likely due to a charge transfer between the C80 cage and the ion.

  15. Li3Gd3Te2O12:Eu3+- an intense red phosphor for solid state lighting applications

    NASA Astrophysics Data System (ADS)

    Tiwari, Hansnath; Asiri Naidu, S.; Varadaraju, U. V.

    2017-02-01

    Li3Gd3-3xEu3xTe2O12 (x=0.05-1.0) phases with garnet structure were synthesized by high temperature solid state reaction and the photoluminescence properties were investigated. The appearance of bands due to intra 4 f transitions of Gd3+ in the excitation spectra recorded by monitoring the 612 nm emission line of the activator indicates Gd3+→Eu3+ energy transfer in this host lattice. Under 395 nm excitation, the electric dipole transition is predominant in the emission spectrum of Eu3+ and is in agreement with the C2 point group (noncentrosymmetric) of the EuO8 polyhedron. The critical concentration of the Eu3+ activator in this series was found to be 0.6 (x=0.2) above which, concentration quenching occurs. The emission intensity of the phosphor composition, Li3Gd2.4Eu0.6Te2O12 is 4 times that of the commercial sample of Y2O3:Eu3+ phosphor.

  16. The effects of Gd3+ doping on the physical structure and photocatalytic performance of Bi2MoO6 nanoplate crystals

    NASA Astrophysics Data System (ADS)

    Yu, Changlin; Wu, Zhen; Liu, Renyue; He, Hongbo; Fan, Wenhong; Xue, Shuangshuang

    2016-06-01

    Gd3+ doped Bi2MoO6 nanoplate crystals were fabricated by solvothermal combined calcination method. The effects of Gd3+ doping with different concentrations on the texture, crystal and optical properties of Bi2MoO6 were investigated by N2 physical adsorption, X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FT-IR) and ultraviolet-visible diffuse reflection spectrum (UV-vis DRS), photoluminescence (PL) spectroscopy, and X-ray photoelectron spectroscopy (XPS). Under simulated solar light irradiation, the influences of Gd3+doping on photocatalytic activity of Bi2MoO6 were evaluated by photocatalytic degradation of Rhodamine B. The characterization results showed that with Gd3+ doping, a contraction of lattice and a decrease in crystallite size occurred. Meanwhile, an increase in surface area over Gd3+ doped Bi2MoO6 was observed. Moreover, Gd3+ doping could obviously enhance the visible light harvesting of Bi2MoO6 and promoted the separation of photogenerated electrons and holes. With optimum Gd3+(6 wt%) doping, Gd/Bi2MoO6 exhibited the best activity and stability in degradation of Rhodamine B.

  17. The role of gangliosides in brain development and the potential benefits of perinatal supplementation.

    PubMed

    Ryan, Jennifer M; Rice, Gregory E; Mitchell, Murray D

    2013-11-01

    The maternal diet provides critical nutrients that can influence fetal and infant brain development and function. This review highlights the potential benefits of maternal dietary ganglioside supplementation on fetal and infant brain development. English-language systematic reviews, preclinical studies, and clinical studies were obtained through searches on PubMed. Reports were selected if they included benefits and harms of maternal ganglioside supplementation during pregnancy or ganglioside-supplemented formula after pregnancy. The potential benefits of ganglioside supplementation were explored by investigating the following: (1) their role in neural development, (2) their therapeutic use in neural injury and disease, (3) their presence in human breast milk, and (4) their use as a dietary supplement during or after pregnancy. Preclinical studies indicate that ganglioside supplementation at high doses (1% of total dietary intake) can significantly increase cognitive development and body weight when given prenatally. However, lower ganglioside supplementation doses have no beneficial cognitive effects, even when given throughout pregnancy and lactation. In human clinical trials, infants given formula supplemented with gangliosides showed increased cognitive development and an increase in ganglioside content. Ganglioside supplementation may promote brain development and function in offspring when administered at the optimum dosage. We propose that prenatal maternal dietary supplementation with gangliosides throughout pregnancy may promote greater long-term effects on brain development and function. Before this concept can be encouraged in preconception clinics, future research and clinical trials are needed to confirm the ability of dietary gangliosides to improve cognitive development, but available results already encourage this area of research.

  18. Altered expression of ganglioside GM3 molecular species and a potential regulatory role during myoblast differentiation.

    PubMed

    Go, Shinji; Go, Shiori; Veillon, Lucas; Ciampa, Maria Grazia; Mauri, Laura; Sato, Chihiro; Kitajima, Ken; Prinetti, Alessandro; Sonnino, Sandro; Inokuchi, Jin-Ichi

    2017-03-08

    Gangliosides (sialic acid-containing glycosphingolipids) help regulate many important biological processes, including cell proliferation, signal transduction, and differentiation, via formation of functional microdomains in plasma membranes. The structural diversity of gangliosides arises from both the ceramide moiety and glycan portion. Recently, differing molecular species of a given ganglioside are suggested to have distinct biological properties, and regulate specific and distinct biological events. Elucidation of the function of each molecular species is important and will provide new insights into ganglioside biology. Gangliosides are also suggested to be involved in skeletal muscle differentiation; however, the differential roles of ganglioside molecular species remain unclear. We describe here striking changes in quantity and quality of gangliosides (particularly GM3) during differentiation of mouse C2C12 myoblast cells, and key roles played by distinct GM3 molecular species at each step of the process.

  19. Ganglioside inserted into PEGylated liposome attenuates anti-PEG immunity.

    PubMed

    Mima, Yu; Abu Lila, Amr S; Shimizu, Taro; Ukawa, Masami; Ando, Hidenori; Kurata, Yasuko; Ishida, Tatsuhiro

    2017-03-28

    Despite the clinical introduction of a vast number of polyethylene glycol (PEG)-conjugated therapeutics, conjugated PEG is also known for an unfortunate inclination toward immunogenicity. Immunogenicity of PEG, manifested by the robust production of anti-PEG IgM, is known to compromise the therapeutic efficacy and/or reduce the tolerance of PEGylated therapeutics. In the present study, we inserted ganglioside into the membrane of PEGylated liposome (PL) to prepare ganglioside-modified PEGylated liposomes (G-PL), and investigated its efficacy in attenuating the anti-PEG IgM response against PL. A single intravenous injection of G-PL significantly attenuated the anti-PEG IgM production, compared with that of naïve PL. In addition, pretreatment with G-PL substantially alleviated the anti-PEG IgM response elicited by a subsequent dose of PL, presumably via inducing B cell tolerance, and as a consequence, this modification abrogated/attenuated the incidence of the rapid clearance of subsequently administrated PL. These results indicate that incorporating gangliosides in PEGylated liposome membrane not only prevents the immunogenicity of PEG but also induces the tolerance of B cells to subsequent doses of the immunogenic PL. Consequently, liposomal membrane modification with ganglioside might represent a promising approach to attenuating the immunogenicity of PEGylated liposomes while preserving their therapeutic efficacy, particularly upon repeated administration.

  20. Anti-Ganglioside Antibodies in Amyotrophic Lateral Sclerosis Revisited

    PubMed Central

    Kollewe, Katja; Wurster, Ulrich; Sinzenich, Thomas; Körner, Sonja; Dengler, Reinhard; Mohammadi, Bahram; Petri, Susanne

    2015-01-01

    Background Amyotrophic Lateral Sclerosis (ALS) is a devastating neurodegenerative disorder with typical onset in the 5th- 6th decade of life. The hypothesis of an autoimmune origin of ALS receives less attention today, but immunological phenomena still seem to be involved and mechanisms such as protective autoimmunity may be important. Detection of antibodies against a variety of gangliosides has been repeatedly described in ALS-patients by several authors, but widely differing frequencies and titres have been reported. Therefore, we investigated the presence of six common antibodies with a commercially available test panel for GA1, GM1, GM2, GD1a, GD1b and GQ1b in a large group of clinically well-characterized ALS patients and compared them to a collective of 200 healthy blood donors. Methods IgG and IgM antibodies to the six gangliosides asialoGM1 (GA1), GM1, GM2, GD1a, GD1b, GQ1b were determined by GanglioCombi ELISA in sera of 84 ALS patients. Results were expressed as a %-ratio of a highly positive control and categorized as negative (<30%), borderline (30–50%), moderately (50–100%) and strongly positive (>100%). The values obtained from 200 Swiss blood donors served as a reference group. Results In twenty-two (26.2%) ALS-patients elevated anti-ganglioside antibodies could be detected: Taking all subspecific antibodies together, IgG antibodies were found in 9/84 (10.7%) and IgM in 15/84 (17.9%) patients. There was no correlation between age, gender, site of onset or survival and anti-ganglioside-positive/-negative titres in ALS-patients. No statistically significant difference in the frequency of anti-ganglioside antibodies compared to the group of healthy blood donors was found. Conclusion Even with this more comprehensive approach, anti-ganglioside antibody frequencies and patterns in our ALS cohort closely resembled the values measured in healthy controls. In accordance with other studies, we did not observe any association of a distinct ALS phenotype

  1. Investigation of Gd3N@C2n(40≤n≤44) family by Raman and inelastic electron tunneling spectroscopy

    NASA Astrophysics Data System (ADS)

    Burke, Brian G.; Chan, Jack; Williams, Keith A.; Ge, Jiechao; Shu, Chunying; Fu, Wujun; Dorn, Harry C.; Kushmerick, James G.; Puretzky, Alexander A.; Geohegan, David B.

    2010-03-01

    The structure and vibrational spectrum of Gd3N@C80 is studied through Raman and inelastic electron tunneling spectroscopy as well as density-functional theory and universal force field calculations. Hindered rotations, shown by both theory and experiment, indicate the formation of a Gd3N-C80 bond which reduces the ideal icosahedral symmetry of the C80 cage. The vibrational modes involving the movement of the encapsulated species are a fingerprint of the interaction between the fullerene cage and the core complex. We present Raman data for the Gd3N@C2n(40≤n≤44) family as well as Y3N@C80 , Lu3N@C80 , and Y3N@C88 for comparison. Conductance measurements have been performed on Gd3N@C80 and reveal a Kondo effect similar to that observed in C60 .

  2. Simultaneous dual-wavelength laser operation at 937 and 1062 nm in Nd3+:Gd3Ga5O12

    NASA Astrophysics Data System (ADS)

    Gao, F.; Sun, G. C.; Li, Y. D.; Dong, Y.; Li, S. T.

    2013-08-01

    Diode-end-pumped continuous-wave (cw) simultaneous dual-wavelength laser operation at 937 and 1062 nm in a single Nd3+:Gd3Ga5O12 (Nd:GGG) crystal was demonstrated. A total output power of 1.12 W at the two fundamental wavelengths was achieved at incident pump power of 17.6 W. The optical-to-optical conversion was up to 6.4% with respect to the incident pump power. To the best of our knowledge, this is first work on cw simultaneous dual-wavelength operation at 937 and 1062 nm in Nd:GGG crystal.

  3. Cancer vaccines: an update with special focus on ganglioside antigens.

    PubMed

    Bitton, Roberto J; Guthmann, Marcel D; Gabri, Mariano R; Carnero, Ariel J L; Alonso, Daniel F; Fainboim, Leonardo; Gomez, Daniel E

    2002-01-01

    Vaccine development is one of the most promising and exciting fields in cancer research; numerous approaches are being studied to developed effective cancer vaccines. The aim of this form of therapy is to teach the patient's immune system to recognize the antigens expressed in tumor cells, but not in normal tissue, to be able to destroy these abnormal cells leaving the normal cells intact. In other words, is an attempt to teach the immune system to recognize antigens that escaped the immunologic surveillance and are by it, therefore able to survive and, in time, disseminate. However each research group developing a cancer vaccine, uses a different technology, targeting different antigens, combining different carriers and adjuvants, and using different immunization schedules. Most of the vaccines are still experimental and not approved by the US or European Regulatory Agencies. In this work, we will offer an update in the knowledge in cancer immunology and all the anticancer vaccine approaches, with special emphasis in ganglioside based vaccines. It has been demonstrated that quantitative and qualitative changes occur in ganglioside expression during the oncogenic transformation. Malignant transformation appears to activate enzymes associated with ganglioside glycosylation, resulting in altered patterns of ganglioside expression in tumors. Direct evidence of the importance of gangliosides as potential targets for active immunotherapy has been suggested by the observation that human monoclonal antibodies against these glycolipids induce shrinkage of human cutaneous melanoma metastasis. Thus, the cellular over-expression and shedding of gangliosides into the interstitial space may play a central role in cell growth regulation, immune tolerance and tumor-angiogenesis, therefore representing a new target for anticancer therapy. Since 1993 researchers at the University of Buenos Aires and the University of Quilmes (Argentina), have taken part in a project carried out by

  4. Nervous system ganglioside composition of normothermic and hibernating dormice (Glis glis).

    PubMed

    Sonnino, S; Ghidoni, R; Malesci, A; Tettamanti, G; Marx, J; Hilbig, R; Rahmann, H

    1984-01-01

    The ganglioside pattern of seven different regions, olfactory bulb, forebrain cortex, midbrain (corpora quadrigemina), cerebellum, brain stem, pons and spinal cord, of nervous system of normothermic and hibernating dormice (Glis glis) were investigated by two dimensional thin layer chromatography and densitometric quantification. Up to thirty different ganglioside spots were resolved, fifteen of which belonging to alkali labile species. Alkali labile gangliosides were present in all the regions obtained from normothermic animals, and their content, expressed as percentage of total ganglioside-bound sialic acid, ranged from a minimum of 10.2% in olfactory bulb, to a maximum of 30.1% in spinal cord. The most abundant alkali labile gangliosides were O-Ac-GT1b, O-Ac-GQ1b and an unidentified one, we coded I3. Alkali labile gangliosides were practically undetectable in hibernating dormice. They could be recognized only in brain stem, 3.3% and olfactory bulb, 0.6%.

  5. Luminescence Enhanced Eu(3+)/Gd(3+) Co-Doped Hydroxyapatite Nanocrystals as Imaging Agents In Vitro and In Vivo.

    PubMed

    Xie, Yunfei; He, Wangmei; Li, Fang; Perera, Thalagalage Shalika Harshani; Gan, Lin; Han, Yingchao; Wang, Xinyu; Li, Shipu; Dai, Honglian

    2016-04-27

    Biocompatible, biodegradable, and luminescent nano material can be used as an alternative bioimaging agent for early cancer diagnosis, which is crucial to achieve successful treatment. Hydroxyapatite (HAP) nanocyrstals have good biocompatibility and biodegradability, and can be used as an excellent host for luminescent rare earth elements. In this study, based on the energy transfer from Gd(3+) to Eu(3+), the luminescence enhanced imaging agent of Eu/Gd codoping HAP (HAP:Eu/Gd) nanocrystals are obtained via coprecipitation with plate-like shape and no change in crystal phase composition. The luminescence can be much elevated (up to about 120%) with a nonlinear increase versus Gd doping content, which is due to the energy transfer ((6)PJ of Gd(3+) → (5)HJ of Eu(3+)) under 273 nm and the possible combination effect of the cooperative upconversion and the successive energy transfer under 394 nm, respectively. Results demonstrate that the biocompatible HAP:Eu/Gd nanocrystals can successfully perform cell labeling and in vivo imaging. The intracellular HAP:Eu/Gd nanocrystals display good biodegradability with a cumulative degradation of about 65% after 72 h. This biocompatible, biodegradable, and luminescence enhanced HAP:Eu/Gd nanocrystal has the potential to act as a fluorescent imaging agent in vitro and in vivo.

  6. Role of Ce4+ in the scintillation mechanism of codoped Gd3Ga3Al2O12:Ce

    DOE PAGES

    Wu, Yuntao; Meng, Fang; Li, Qi; ...

    2014-10-17

    To control the time-response performance of widely used cerium-activated scintillators in cutting-edge medical-imaging devices, such as time-of-flight positron-emission tomography, a comprehensive understanding of the role of Ce valence states, especially stable Ce4+, in the scintillation mechanism is essential. However, despite some progress made recently, an understanding of the physical processes involving Ce4+ is still lacking. The aim of this work is to clarify the role of Ce4+ in scintillators by studying Ca2+ codoped Gd3Ga3Al2O12∶Ce (GGAG∶Ce). By using a combination of optical absorption spectra and x-ray absorption near-edge spectroscopies, the correlation between Ca2+codoping content and the Ce4+ fraction is seen. The energy-levelmore » diagrams of Ce3+ and Ce4+ in the Gd3Ga3Al2O12 host are established by using theoretical and experimental methods, which indicate a higher position of the 5d1 state of Ce4+ in the forbidden gap in comparison to that of Ce3+. Underlying reasons for the decay-time acceleration resulting from Ca2+ codoping are revealed, and the physical processes of the Ce4+-emission model are proposed and further demonstrated by temperature-dependent radioluminescence spectra under x-ray excitation.« less

  7. Garnet-to-perovskite transition in Gd3Sc2Ga3O12 at high pressure and high temperature.

    PubMed

    Lin, Chuanlong; Liu, Jing; Lin, Jung-Fu; Li, Xiaodong; Li, Yanchun; Zhang, Qingli; Xiong, Lun; Li, Rui

    2013-01-07

    The structural phase transition of gadolinium-scandium-gallium garnet (Gd(3)Sc(2)Ga(3)O(12), GSGG) has been studied at high pressure and high temperature using the synchrotron X-ray diffraction technique in a laser-heated diamond anvil cell. The GSGG garnet transformed to an orthorhombic perovskite structure at approximately 24 GPa after laser heating to 1500-2000 K. The garnet-to-perovskite phase transition is associated with an ∼8% volume reduction and an increase in the coordination number of the Ga(3+) or Sc(3+) ion. The orthorhombic perovskite GSGG has bulk modulus B(0) = 194(15) GPa with B(0)' = 5.3(8), exhibiting slightly less compression than the cubic garnet structure of GSGG with B(0) = 157(15) GPa and B(0)' = 6.5(10). Upon compression at room temperature, the cubic GSGG garnet became amorphous at ∼65 GPa. Coupled with the amorphous-to-perovskite phase transition in Y(3)Fe(5)O(12) and Gd(3)Ga(5)O(12) at high-pressure-temperature conditions, we conclude that amorphization should represent a new thermodynamic state resulting from hindrance of the garnet-to-perovskite phase transition, whereas the garnet-to-amorphous transition in rare-earth garnets should be kinetically hindered at room temperature.

  8. Metal ion blockage of tritium incorporation into gamma-carboxyglutamic acid of prothrombin. Stoichiometry of gamma-carboxyglutamic acid to Gd3+ for the high affinity sites

    SciTech Connect

    Bajaj, S.P.; Saini, R.; Katz, A.; Cai, G.Z.; Maki, S.L.; Brodsky, G.L.

    1988-07-15

    Prothrombin possesses two high affinity and four low affinity gamma-carboxyglutamic acid (Gla)-dependent gadolinium binding sites. Earlier work has shown that tritium can be specifically incorporated at the gamma-carbon of Gla in proteins at pH 5. In the present work we show that inclusion of saturating concentrations of Ca2+ in nondenaturing buffer systems ranging from pH 5.5 to 8.5 prevents the exchange of tritium into all 10 Gla residues of prothrombin. Similarly, saturating concentrations of Gd3+ prevent tritium incorporation into Gla at pH 5.5. Positive cooperativity was observed for the binding of Gd3+ to human prothrombin (at pH 5.5) for the two high affinity sites (Kd congruent to 35 nM). The four low affinity sites bind Gd3+ with a Kd congruent to 5 microM. Incubation of prothrombin ranging in concentrations from 10 to 40 microM with 2 eq of Gd3+ at pH 5.5 prevents 5.7 (average of seven determinations) Gla residues from tritium incorporation. Sedimentation velocity experiments conducted at pH 5.5 indicate that prothrombin in the presence of saturating concentrations of Gd3+ polymerizes, most likely, to a trimer. Further, in the presence of 2 eq of Gd3+, calculated percent weight average concentration of monomer prothrombin is congruent to 100% at 10 microM, approximately equal to 95% at 20 microM, and congruento to 80% at 40 microM protein concentration. Thus, it appears that under conditions in which prothrombin primarily exists as a monomer, occupancy of the initial two metal binding sites by Gd3+ involves six Gla residues.

  9. Assessment of the Molecular Expression and Structure of Gangliosides in Brain Metastasis of Lung Adenocarcinoma by an Advanced Approach Based on Fully Automated Chip-Nanoelectrospray Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Zamfir, Alina D.; Serb, Alina; Vukeli, Željka; Flangea, Corina; Schiopu, Catalin; Fabris, Dragana; Kalanj-Bognar, Svjetlana; Capitan, Florina; Sisu, Eugen

    2011-12-01

    Gangliosides (GGs), sialic acid-containing glycosphingolipids, are known to be involved in the invasive/metastatic behavior of brain tumor cells. Development of modern methods for determination of the variations in GG expression and structure during neoplastic cell transformation is a priority in the field of biomedical analysis. In this context, we report here on the first optimization and application of chip-based nanoelectrospray (NanoMate robot) mass spectrometry (MS) for the investigation of gangliosides in a secondary brain tumor. In our work a native GG mixture extracted and purified from brain metastasis of lung adenocarcinoma was screened by NanoMate robot coupled to a quadrupole time-of-flight MS. A native GG mixture from an age-matched healthy brain tissue, sampled and analyzed under identical conditions, served as a control. Comparative MS analysis demonstrated an evident dissimilarity in GG expression in the two tissue types. Brain metastasis is characterized by many species having a reduced N-acetylneuraminic acid (Neu5Ac) content, however, modified by fucosylation or O-acetylation such as Fuc-GM4, Fuc-GM3, di- O-Ac-GM1, O-Ac-GM3. In contrast, healthy brain tissue is dominated by longer structures exhibiting from mono- to hexasialylated sugar chains. Also, significant differences in ceramide composition were discovered. By tandem MS using collision-induced dissociation at low energies, brain metastasis-associated GD3 (d18:1/18:0) species as well as an uncommon Fuc-GM1 (d18:1/18:0) detected in the normal brain tissue could be structurally characterized. The novel protocol was able to provide a reliable compositional and structural characterization with high analysis pace and at a sensitivity situated in the fmol range.

  10. Zika virus and neurologic autoimmunity: the putative role of gangliosides.

    PubMed

    Anaya, Juan-Manuel; Ramirez-Santana, Carolina; Salgado-Castaneda, Ignacio; Chang, Christopher; Ansari, Aftab; Gershwin, M Eric

    2016-03-21

    An increasing number of severe neurological complications associated with Zika virus (ZIKV), chiefly Guillain-Barré syndrome (GBS) and primary microcephaly, have led the World Health Organization to declare a global health emergency. Molecular mimicry between glycolipids and surface molecules of infectious agents explain most of the cases of GBS preceded by infection, while a direct toxicity of ZIKV on neural cells has been raised as the main mechanism by which ZIKV induces microcephaly. Gangliosides are crucial in brain development, and their expression correlates with neurogenesis, synaptogenesis, synaptic transmission, and cell proliferation. Targeting the autoimmune response to gangliosides may represent an underexploited opportunity to examine the increased incidence of neurological complications related to ZIKV infection.

  11. Differential Distribution of Major Brain Gangliosides in the Adult Mouse Central Nervous System

    PubMed Central

    Vajn, Katarina; Viljetić, Barbara; Degmečić, Ivan Večeslav; Schnaar, Ronald L.; Heffer, Marija

    2013-01-01

    Gangliosides - sialic acid-bearing glycolipids - are major cell surface determinants on neurons and axons. The same four closely related structures, GM1, GD1a, GD1b and GT1b, comprise the majority of total brain gangliosides in mammals and birds. Gangliosides regulate the activities of proteins in the membranes in which they reside, and also act as cell-cell recognition receptors. Understanding the functions of major brain gangliosides requires knowledge of their tissue distribution, which has been accomplished in the past using biochemical and immunohistochemical methods. Armed with new knowledge about the stability and accessibility of gangliosides in tissues and new IgG-class specific monoclonal antibodies, we investigated the detailed tissue distribution of gangliosides in the adult mouse brain. Gangliosides GD1b and GT1b are widely expressed in gray and white matter. In contrast, GM1 is predominately found in white matter and GD1a is specifically expressed in certain brain nuclei/tracts. These findings are considered in relationship to the hypothesis that gangliosides GD1a and GT1b act as receptors for an important axon-myelin recognition protein, myelin-associated glycoprotein (MAG). Mediating axon-myelin interactions is but one potential function of the major brain gangliosides, and more detailed knowledge of their distribution may help direct future functional studies. PMID:24098718

  12. Anti-ganglioside antibodies are removed from circulation in mice by neuronal endocytosis

    PubMed Central

    Cunningham, Madeleine E.; McGonigal, Rhona; Meehan, Gavin R.; Barrie, Jennifer A.; Yao, Denggao; Halstead, Susan K.

    2016-01-01

    See van Doorn and Jacobs (doi:10.1093/brain/aww078) for a scientific commentary on this article.   In axonal forms of Guillain-Barré syndrome, anti-ganglioside antibodies bind gangliosides on nerve surfaces, thereby causing injury through complement activation and immune cell recruitment. Why some nerve regions are more vulnerable than others is unknown. One reason may be that neuronal membranes with high endocytic activity, including nerve terminals involved in neurotransmitter recycling, are able to endocytose anti-ganglioside antibodies from the cell surface so rapidly that antibody-mediated injury is attenuated. Herein we investigated whether endocytic clearance of anti-ganglioside antibodies by nerve terminals might also be of sufficient magnitude to deplete circulating antibody levels. Remarkably, systemically delivered anti-ganglioside antibody in mice was so avidly cleared from the circulation by endocytosis at ganglioside-expressing plasma membranes that it was rapidly rendered undetectable in serum. A major component of the clearance occurred at motor nerve terminals of neuromuscular junctions, from where anti-ganglioside antibody was retrogradely transported to the motor neuron cell body in the spinal cord, recycled to the plasma membrane, and secreted into the surrounding spinal cord. Uptake at the neuromuscular junction represents a major unexpected pathway by which pathogenic anti-ganglioside antibodies, and potentially other ganglioside binding proteins, are cleared from the systemic circulation and also covertly delivered to the central nervous system. PMID:27017187

  13. Brain gangliosides in hibernating dormice (Glis glis) and cold-exposed laboratory mice.

    PubMed

    Mühleisen, M; Hilbig, R; Rahmann, H

    1984-01-01

    The concentration of proteins, sialo-glycoproteins and gangliosides and the ganglioside composition of 8 brain regions from normothermic and hibernating fat dormice (Glis glis) and from laboratory mice being acclimated to 6, 22 and 28 degrees C were investigated. During hibernation the concentration of sialo-glycoproteins and gangliosides decreased significantly in brain of dormice; the protein content remained uninfluenced. Cold-exposure of laboratory mice yielded generally a slightly decreased sialo-glycoprotein concentration in brain; the data on ganglioside concentration in the CNS were not uniform. The ganglioside composition of brain of laboratory mice being kept at different environmental temperatures did not show any alterations. The brain gangliosides of hibernating dormice in contrast to their normothermic counterparts are more polar (higher amount of GTlb and GQlb.). Most striking is the complete absence of a distinct ganglioside fraction (O-acetylated-GTlb) during hibernation. Brain gangliosides of normothermic dormice were found to be more sensitive against neuraminidase treatment than those of hibernating animals. The results are discussed with regard to modulatory functions of neuronal gangliosides for the process of synaptic transmission during seasonal adaptation.

  14. Gangliosides During Tumor Progression in Patients With Prostate Cancer

    DTIC Science & Technology

    2004-07-01

    LSCFM, Thiruverkadu S. Saravanan, Ph.D. and Meena Verma, M.B., B.S., for other technical support. 15 References 1. P. M . Gullino , Prostaglandins and...121-135. 3. G. Alessandri, P. Cornaglia-Ferraris, P. M . Gullino , Angiogenic and angiostatic microenvironment in tumors-role of gangliosides. Acta...Wiegandt (Ed), Glycolipids, Elsevier, Amsterdam, 1985, pp. 199-260. 11. M . L . Freimer, K. McIntosh, R. A. Adams, C. R. Alving, D. B. Drachman

  15. Broadband Yellowish-Green Emitting Ba4Gd3Na3(PO4)6F2:Eu(2+) Phosphor: Structure Refinement, Energy Transfer, and Thermal Stability.

    PubMed

    Fu, Xiaopeng; Lü, Wei; Jiao, Mengmeng; You, Hongpeng

    2016-06-20

    A series of Ba4Gd3Na3(PO4)6F2:Eu(2+) phosphors with a broad emitting band have been synthesized by a traditional solid state reaction. The crystal structural and photoluminescence properties of Ba4Gd3Na3(PO4)6F2:Eu(2+) are investigated. The different crystallographic sites of Eu(2+) in Ba4Gd3Na3(PO4)6F2:Eu(2+) phosphors have been verified by means of their photoluminescence (PL) properties and decay times. Energy transfer between Eu(2+) ions, analyzed by excitation, emission, and PL decay behavior, has been indicated to be a dipole-dipole mechanism. Moreover, the luminescence quantum yield as well as the thermal stability of the Ba4Gd3Na3(PO4)6F2:Eu(2+) phosphor have been investigated systematically. The as-prepared Ba4Gd3Na3(PO4)6F2:Eu(2+) phosphor can act as a promising candidate for n-UV convertible white LEDs.

  16. The gadolinium nitride selenides Gd3NSe3 and Gd23N5Se27: Three connectivity types of [NGd4]9+ tetrahedra and fivefold coordinated Gd3+ cations

    NASA Astrophysics Data System (ADS)

    Schurz, Christian M.; Talmon-Gros, Pia; Lissner, Falk; Schleid, Thomas

    2013-03-01

    The gadolinium nitride selenides Gd3NSe3 and Gd23N5Se27 are formed by the reaction of gadolinium metal with its triiodide, cesium azide and selenium along with an excess of cesium iodide as flux within seven days at 900 °C in torch-sealed evacuated silica ampoules. The dominant phase Gd3NSe3 crystallizes isotypically with Sm3NS3 in the orthorhombic space group Pnma (unit cell: a = 1256.71(9) pm, b = 398.65(3) pm, c = 1318.32(9) pm, Z = 4). Thus nitride-centered (Gd4)12+ tetrahedra are linked via two vertices each forming {[}∞1 chains (t = terminal, v = vertex-shared) along [010], which become interconnected by three crystallographically different Se2- anions. Beside C-type of Gd2Se3 and at least another unknown phase powder diffraction experiments show additional reflections indicating the second nitride selenide Gd23N5Se27. This new compound crystallizes non-centrosymmetrically in the monoclinic space group Pc (unit cell: a = 2854.87(19) pm, b = 1227.94(8) pm, c = 747.62(5) pm, β = 94.215(3)°, Z = 2). Here, {(}∞2 and {(}∞2 layers embed the main structural features of isolated [NGd4]9+ tetrahedra and isolated congonial [N2Gd6]12+ bitetrahedra. Another particularity is the fivefold coordination of the (Gd4)3+ cations with one short contact to N3- and four relatively short bonds to four Se2- anions, respectively.

  17. A comparison of the ganglioside distributions of fat tissues in various animals by two-dimensional thin layer chromatography.

    PubMed

    Ohashi, M

    1979-01-01

    The ganglioside distributions of various fat tissues from human, rabbit, rat, mouse, chicken and frog were compared with pig adipose gangliosides by two-dimensional thin layer chromatography. It was found that there is a remarkable species variation in ganglioside distribution, especially in the composition and relative concentration of complex gangliosides. Differing from pig adipose tissues, those of human, rabbit, rat, mouse, chicken, but not frog, contained GM3 as a most abundant ganglioside. The data for human, rabbit and chicken indicated a simple distribution of only NeuAc-type gangliosides, while those for rat and mouse indicated a rather complicated pattern containing both NeuAc- and NeuGc-type gangliosides. The ganglioside pattern of the frog fat body differed markedly from those of mammalian fat tissues because of the presence of three different, unusual monosialosylgangliosides as major components. In other respects, a substantial amount of disialosylgangliosides was commonly found in all animal fat tissues.

  18. Novel Ganglioside-mediated Entry of Botulinum Neurotoxin Serotype D into Neurons

    SciTech Connect

    Kroken, Abby R.; Karalewitz, Andrew P.-A.; Fu, Zhuji; Kim, Jung-Ja P.; Barbieri, Joseph T.

    2012-02-07

    Botulinum Neurotoxins (BoNTs) are organized into seven serotypes, A-G. Although several BoNT serotypes enter neurons through synaptic vesicle cycling utilizing dual receptors (a ganglioside and a synaptic vesicle-associated protein), the entry pathway of BoNT/D is less well understood. Although BoNT/D entry is ganglioside-dependent, alignment and structural studies show that BoNT/D lacks key residues within a conserved ganglioside binding pocket that are present in BoNT serotypes A, B, E, F, and G, which indicate that BoNT/D-ganglioside interactions may be unique. In this study BoNT/D is shown to have a unique association with ganglioside relative to the other BoNT serotypes, utilizing a ganglioside binding loop (GBL, residues Tyr-1235-Ala-1245) within the receptor binding domain of BoNT/D (HCR/D) via b-series gangliosides, including GT1b, GD1b, and GD2. HCR/D bound gangliosides and entered neurons dependent upon the aromatic ring of Phe-1240 within the GBL. This is the first BoNT-ganglioside interaction that is mediated by a phenylalanine. In contrast, Trp-1238, located near the N terminus of the ganglioside binding loop, was mostly solvent-inaccessible and appeared to contribute to maintaining the loop structure. BoNT/D entry and intoxication were enhanced by membrane depolarization via synaptic vesicle cycling, where HCR/D colocalized with synaptophysin, a synaptic vesicle marker, but immunoprecipitation experiments did not detect direct association with synaptic vesicle protein 2. Thus, BoNT/D utilizes unique associations with gangliosides and synaptic vesicles to enter neurons, which may facilitate new neurotoxin therapies.

  19. Continuous-wave laser operation of diode-pumped Tm-doped Gd3Ga5O12 crystal

    NASA Astrophysics Data System (ADS)

    Wang, Yi; Lan, Jinglong; Zhou, Zhiyong; Guan, Xiaofeng; Xu, Bin; Xu, Huiying; Cai, Zhiping; Wang, Yan; Tu, Chaoyang

    2017-04-01

    We report on a diode-pumped Tm:Gd3Ga5O12 (GGG) laser at 2004 nm operated in continuous-wave mode with two-mirror linear cavity configuration. The maximum output power reaches 0.58 W with laser threshold absorbed pump power of about 0.39 W and overall slope efficiency of about 18.4%, which is believed to be the highest output power for Tm:GGG laser up to now. The Tm:GGG laser shows obvious thermally induced saturation of the output power, which indicated that power and efficiency scaling could be furtherly realized by more efficient thermal removal of the laser crystal.

  20. Mechanochemical preparation of nanocrystalline NaYF4:Gd3+/Yb3+/Tm3+: An efficient upconversion phosphor

    NASA Astrophysics Data System (ADS)

    Zhang, Jun; Riesen, Hans

    2015-11-01

    We report on a mechanochemical preparation route for NaYF4:Gd3+/Yb3+/Tm3+ nanoparticles by ball-milling NaF, YF3, GdF3, YbF3 and TmF3 at room temperature. An analysis by XRD and TEM demonstrates that the resulting materials are mainly (∼88% after 4 h ball-milling) in the hexagonal phase and are on the nanoscale with an average crystallite size of ∼20 nm. The prepared nanoparticles display efficient upconversion emission; upon excitation by a 980 nm laser diode, bright visible blue light emission can be observed. However, in accord with previous results, the strongest emission is observed in the NIR at 800 nm.

  1. The Exchange Coupling of Gd3+- and Cr3+-Ions in Paramagnetic GdCrO3 (In German)

    NASA Astrophysics Data System (ADS)

    Dräger, K.

    1986-03-01

    Polycrystalline samples of stoichiometric GdCrO3 have been investigated by ESR at 9.4 GHz. In the temperature range between 175 K and 520 K one broad absorption with a Lorentzian line shape and a g-factor of 2.024 has been observed. Attributing the absorption exclusively to the Gd -ion it can be shown that the temperature dependence of the ESR-intensity follows the predictions of a cluster-model. The energy describing the coupling of a single Gd3+-ion to the surrounding Cr3+-ions is found to be ΔE(Gd) = 170 cm-1. Taking advantage of the similarity within the orthochromites it is possible to determine at the same time the exchange - coupling of Cr3+-ions to their identical nearest neighbours as ΔE(Cr) = 293 cm-1. The relative strength of these couplings given by 0.60 is compatible with other experimental issues.

  2. Atomistic study on the site preference and lattice vibration of Gd3-xYxCo29T4B10 (T=Al and Ge)

    NASA Astrophysics Data System (ADS)

    Cheng, Hai-Xia; Wang, Xiao-Xu; Hu, Yao-Wen; Zhang, Guo-Hua; Shen, Jiang; Qian, Ping; Chen, Nan-Xian

    2015-04-01

    The effects of the Y substitution for Gd on the structural stability and the site preference of intermetallics Gd3-xYxCo29T4B10 (T=Al and Ge) are studied by using a series of interatomic pair potentials. The calculated results show Y can stabilize Gd3-xYxCo29T4B10 with the tetragonal structure, and Y substitute for Gd with a strong preference for the 2b sites. The calculated lattice parameters are in good agreement with the experimental data. Furthermore, the total and partial phonon densities of states are evaluated for the Gd3-xYxCo29T4B10 compounds with the tetragonal structure. A qualitative analysis is carried out with the relevant potentials for the vibrational modes, which makes it possible to predict some properties related to lattice vibration.

  3. Highly biocompatible TiO2:Gd3+ nano-contrast agent with enhanced longitudinal relaxivity for targeted cancer imaging

    NASA Astrophysics Data System (ADS)

    Chandran, Parwathy; Sasidharan, Abhilash; Ashokan, Anusha; Menon, Deepthy; Nair, Shantikumar; Koyakutty, Manzoor

    2011-10-01

    We report the development of a novel magnetic nano-contrast agent (nano-CA) based on Gd3+ doped amorphous TiO2 of size ~25 nm, exhibiting enhanced longitudinal relaxivity (r1) and magnetic resonance (MR) contrasting together with excellent biocompatibility. Quantitative T1 mapping of phantom samples using a 1.5 T clinical MR imaging system revealed that the amorphous phase of doped titania has the highest r1 relaxivity which is ~2.5 fold higher than the commercially used CA Magnevist™. The crystalline (anatase) samples formed by air annealing at 250 °C and 500 °C showed significant reduction in r1 values and MR contrast, which is attributed to the loss of proton-exchange contribution from the adsorbed water and atomic re-arrangement of Gd3+ ions in the crystalline host lattice. Nanotoxicity studies including cell viability, plasma membrane integrity, reactive oxygen stress and expression of pro-inflammatory cytokines, performed on human primary endothelial cells (HUVEC), human blood derived peripheral blood mononuclear cells (PBMC) and nasopharyngeal epidermoid carcinoma (KB) cell line showed excellent biocompatibility up to relatively higher doses of 200 μg ml-1. The potential of this nano-CA to cause hemolysis, platelet aggregation and plasma coagulation were studied using human peripheral blood samples and found no adverse effects, illustrating the possibility of the safe intravenous administration of these agents for human applications. Furthermore, the ability of these agents to specifically detect cancer cells by targeting molecular receptors on the cell membrane was demonstrated on folate receptor (FR) positive oral carcinoma (KB) cells, where the folic acid conjugated nano-CA showed receptor specific accumulation on cell membrane while leaving the normal fibroblast cells (L929) unstained. This study reveals that the Gd3+ doped amorphous TiO2 nanoparticles having enhanced magnetic resonance contrast and high biocompatibility is a promising candidate for

  4. GM1 Ganglioside Treatment Facilitates Behavioral Recovery from Bilateral Brain Damage

    NASA Astrophysics Data System (ADS)

    Sabel, Bernhard A.; Slavin, Mary D.; Stein, Donald G.

    1984-07-01

    Adult rats with bilateral lesions of the caudate nucleus were treated with GM1 ganglioside. Although animals injected with a control solution were severely impaired in their ability to learn a complex spatial task, those treated with ganglioside were able to learn spatial reversals.

  5. Prevalence, specificity and functionality of anti-ganglioside antibodies in neuropathy associated with IgM monoclonal gammopathy.

    PubMed

    Stork, Abraham C J; Jacobs, Bart C; Tio-Gillen, Anne P; Eurelings, Marijke; Jansen, Marc D; van den Berg, Leonard H; Notermans, Nicolette C; van der Pol, W-Ludo

    2014-03-15

    IgM antibodies against gangliosides and their complexes were studied in sera from 54 patients with polyneuropathy and IgM monoclonal gammopathy (IgM-PNP) without anti-MAG antibodies. Anti-ganglioside antibodies were found in 19 (35%) patients. Five (9%) patients had antibodies against ganglioside complexes. IgM antibodies against gangliosides activated complement in vitro. Light chain usage was restricted to kappa or lambda in most, but not all patients. In conclusion, anti-ganglioside antibodies in IgM-PNP are common, display pathogenic properties and do not always arise from a monoclonal B cell proliferation.

  6. Enhanced near-infrared emission in phase and size controlled NaLnF4: Pr3+-Yb3+ (Ln = Gd3+ and Y3+) nanocrystals

    NASA Astrophysics Data System (ADS)

    Ye, Song; Hu, Rongxuan; Wang, Huiyun; Wang, Deping

    2015-01-01

    NaLnF4 (Ln = Y, Gd): Pr3+, Yb3+ nanocrystals were prepared through a facile modified solvothermal method, in which the cubic to hexagonal phase transformation and size evaluation of NaLnF4 nanocrystals could be well controlled by carefully adjusting Gd3+ content. In this system, the infrared emission associated with Yb3+: 2F5/2 → 2F7/2 transition could be obtained under the excitation of Pr3+: 3P0 energy level as a result of efficient energy transfer from Pr3+ to Yb3+. The structural and spectral measurement indicated that the energy transfer efficiency from Pr3+ to Yb3+ firstly increased with the increase of Gd3+ content due to the formation of a higher percentage of hexagonal phase NaLnF4 in the final production, and then decreased with further increase in Gd3+ content due to the expansion of NaLnF4 unit-cell volume. However, a monotonous increase in Yb3+ infrared emission intensity could be observed with the increasing of Gd3+ content until the radiative emission was suppressed by the nonradiative transition originating from the surface defects in smaller NaLnF4 nanocrystals.

  7. Synthesis and luminescent properties of Gd3Ga2Al3O12 phosphors doped with Eu3+ or Ce3+

    NASA Astrophysics Data System (ADS)

    Oh, M. J.; Kim, H. J.

    2016-09-01

    Eu3+-or Ce3+-doped gadolinium gallium aluminum garnet (GGAG), Gd3Ga2Al3O12, phosphors are fabricated using solid-state reactions with Gd2O3, Ga2O3, Al2O3, CeO2 and Eu2O3 powders. The Eu3+-or Ce3+-doped Gd3Ga2Al3O12 phosphors are sintered at 1300 °C or 1600 °C for 5 hours by using an electric furnace under normal atmosphere. X-ray diffraction and field-emission scanning electron microscopy studies are carried out in order to analyze the physical properties of these materials, and their luminescence properties are also measured by using UV and X-ray sources. The Eu3+-or Ce3+-doped Gd3Ga2Al3O12 phosphors show higher light yields in comparison to commercial phosphors such as Gd2O2S:Tb (gadox). This indicates that Gd3Ga2Al3O12:Eu3+ phosphors are promising materials for use in X-ray imaging and dose monitoring at proton beamlines.

  8. Gd3+ spin-lattice relaxation via multi-band conduction electrons in Y(1-x)Gd(x)In3: an electron spin resonance study.

    PubMed

    Cabrera-Baez, M; Iwamoto, W; Magnavita, E T; Osorio-Guillén, J M; Ribeiro, R A; Avila, M A; Rettori, C

    2014-04-30

    Interest in the electronic structure of the intermetallic compound YIn3 has been renewed with the recent discovery of superconductivity at T ∼ 1 K, which may be filamentary in nature. In this work we perform electron spin resonance (ESR) experiments on Gd(3+) doped YIn3 (Y1-xGdxIn3; 0.001 ⪅ x ⩽̸ 0.08), showing that the spin-lattice relaxation of the Gd(3+) ions, due to the exchange interaction between the Gd(3+) localized magnetic moment and the conduction electrons (ce), is processed via the presence of s-, p- and d-type ce at the YIn3 Fermi level. These findings are revealed by the Gd(3+) concentration dependence of the Korringa-like relaxation rate d(ΔH)/dT and g-shift (Δg = g - 1.993), that display bottleneck relaxation behavior for the s-electrons and unbottleneck behavior for the p- and d-electrons. The Korringa-like relaxation rates vary from 22(2) Oe/K for x ⪅ 0.001 to 8(2) Oe/K for x = 0.08 and the g-shift values change, respectively, from a positive Δg = +0.047(10) to a negative Δg = -0.008(4). Analysis in terms of a three-band ce model allows the extraction of the corresponding exchange interaction parameters Jfs, Jfp and Jfd.

  9. Effect of Ga(3+) and Gd(3+) ions substitution on the structural and optical properties of Ce(3+) -doped yttrium aluminium garnet phosphor nanopowders.

    PubMed

    Wako, A H; Dejene, F B; Swart, H C

    2016-11-01

    The structural and optical properties of commercially obtained Y3 Al5 O12 :Ce(3)(+) phosphor were investigated by replacing Al(3)(+) with Ga(3)(+) and Y(3)(+) with Gd(3)(+) in the Y3 Al5 O12 :Ce(3)(+) structure to form Y3 (Al,Ga)5 O12 :Ce(3)(+) and (Y,Gd)3 Al5 O12 :Ce(3)(+) . X-Ray diffraction (XRD) results showed slight 2-theta peak shifts to lower angles when Ga(3)(+) was used and to higher angles when Gd(3)(+) was used, with respect to peaks from Y3 Al5 O12 :Ce(3)(+) and JCPDS card no. 73-1370. This could be attributed to induced crystal-field effects due to the different ionic sizes of Ga(3)(+) and Gd(3)(+) compared with Al(3)(+) and Y(3)(+) . The photoluminescence (PL) spectra showed broad excitation from 350 to 550 nm with a maximum at 472 nm, and broad emission bands from 500 to 650 nm, centred at 578 nm for Y3 Al5 O12 :Ce(3)(+) arising from the 5d → 4f transition of Ce(3)(+) . PL revealed a blue shift for Ga(3)(+) substitution and a red shift for Gd(3)(+) substitution. UV-Vis showed two absorption peaks at 357 and 457 nm for Y3 Al5 O12 :Ce(3)(+) , with peaks shifting to 432 nm for Ga(3)(+) and 460 nm for Gd(3)(+) substitutions. Changes in the trap levels or in the depth and number of traps due to Ce(3)(+) were analysed using thermoluminescence (TL) spectroscopy. This revealed the existence of shallow and deep traps. It was observed that Ga(3)(+) substitution contributes to the shallowest traps at 74 °C and fewer deep traps at 163 °C, followed by Gd(3)(+) with shallow traps at 87 °C and deep traps at 146 °C. Copyright © 2016 John Wiley & Sons, Ltd.

  10. Photoluminescence properties of phosphors based on Lu3+-stabilized Gd3Al5O12:Tb3+/Ce3+ garnet solid solutions

    NASA Astrophysics Data System (ADS)

    Li, Jinkai; Li, Ji-Guang; Li, Xiaodong; Sun, Xudong

    2016-12-01

    The Gd3Al5O12:Tb/Ce (GdAG:Tb/Ce) garnet solutions effectively stabilized by Lu3+ have been achieved by calcining their precursor at 1300 °C. Detailed characterizations are given to the materials in terms of XRD, FE-SEM, BET, PL/PLE, and fluorescence decay analysis. The occurrence of Gd3+ and Tb3+ transitions from the photoluminescence excitation spectrum monitoring the Ce3+ yellow emission strongly confirmed the efficient Gd3+ → Ce3+ and Tb3+ → Ce3+ energy transfer. The [(Gd0.8Lu0.2)0.99-xCe0.01Tbx]AG (x = 0-0.1) phosphors with good dispersion and uniform particle size exhibit various luminescent properties under different excitation wavelength of 275, 338, and 457 nm, respectively. The photoluminescence comparison indicated that owing to the Gd3+ → Ce3+ and Tb3+ → Ce3+ energy transfer, the best luminescent phosphor [(Gd0.8Lu0.2)0.89Ce0.01 Tb0.1]AG is almost identical to the well-known YAG:Ce, higher than LuAG:Ce in emission intensity, and has a substantially red-shifted emission band that is desired for warm-white lighting. The Tb3+ → Ce3+ energy transfer was suggested to be electric multipolar interactions, and the processes of energy migration among the optically active Gd3+, Tb3+, and Ce3+ ions were discussed in detail. Fluorescence decay analysis found the lifetime for the Ce3+ emission hardly changes with the Tb3+ incorporation. The [(Gd0.8Lu0.2)0.99-xCe0.01Tbx]AG garnets developed in this work may serve as a new type of phosphor that hopefully meets the requirements of various lighting, optical display, and scintillation applications.

  11. Targeting O-Acetyl-GD2 Ganglioside for Cancer Immunotherapy.

    PubMed

    Fleurence, Julien; Fougeray, Sophie; Bahri, Meriem; Cochonneau, Denis; Clémenceau, Béatrice; Paris, François; Heczey, Andras; Birklé, Stéphane

    2017-01-01

    Target selection is a key feature in cancer immunotherapy, a promising field in cancer research. In this respect, gangliosides, a broad family of structurally related glycolipids, were suggested as potential targets for cancer immunotherapy based on their higher abundance in tumors when compared with the matched normal tissues. GD2 is the first ganglioside proven to be an effective target antigen for cancer immunotherapy with the regulatory approval of dinutuximab, a chimeric anti-GD2 therapeutic antibody. Although the therapeutic efficacy of anti-GD2 monoclonal antibodies is well documented, neuropathic pain may limit its application. O-Acetyl-GD2, the O-acetylated-derivative of GD2, has recently received attention as novel antigen to target GD2-positive cancers. The present paper examines the role of O-acetyl-GD2 in tumor biology as well as the available preclinical data of anti-O-acetyl-GD2 monoclonal antibodies. A discussion on the relevance of O-acetyl-GD2 in chimeric antigen receptor T cell therapy development is also included.

  12. Targeting O-Acetyl-GD2 Ganglioside for Cancer Immunotherapy

    PubMed Central

    Fleurence, Julien; Fougeray, Sophie; Bahri, Meriem; Cochonneau, Denis; Clémenceau, Béatrice; Paris, François; Heczey, Andras

    2017-01-01

    Target selection is a key feature in cancer immunotherapy, a promising field in cancer research. In this respect, gangliosides, a broad family of structurally related glycolipids, were suggested as potential targets for cancer immunotherapy based on their higher abundance in tumors when compared with the matched normal tissues. GD2 is the first ganglioside proven to be an effective target antigen for cancer immunotherapy with the regulatory approval of dinutuximab, a chimeric anti-GD2 therapeutic antibody. Although the therapeutic efficacy of anti-GD2 monoclonal antibodies is well documented, neuropathic pain may limit its application. O-Acetyl-GD2, the O-acetylated-derivative of GD2, has recently received attention as novel antigen to target GD2-positive cancers. The present paper examines the role of O-acetyl-GD2 in tumor biology as well as the available preclinical data of anti-O-acetyl-GD2 monoclonal antibodies. A discussion on the relevance of O-acetyl-GD2 in chimeric antigen receptor T cell therapy development is also included. PMID:28154831

  13. Direct evidence that ganglioside is an integral component of the thyrotropin receptor

    SciTech Connect

    Kielczynski, W.; Harrison, L.C.; Leedman, P.J. )

    1991-03-01

    Gangliosides were extracted from purified human and porcine thyrotropin (TSH) receptors (TSH-R) and were detected by probing with an {sup 125}I-labeled sialic acid-specific lectin, Limax flavus agglutinin. Gangliosides copurified with human and porcine TSH-R migrated between monosialoganglioside GM1 and disialoganglioside GD1a. Ceramide glycanase digestion of the purified human TSH-R-associated glycolipid confirmed its ganglioside nature. It was resistant to Vibrio cholerae sialidase, which digest all gangliosides except GM1, but was sensitive to Arthrobacter ureafaciens sialidase, which digests all gangliosides including GM1. These findings indicate that the human TSH-R contains ganglioside that belongs to the galactosyl({beta}1{r arrow} 3)-N-acetylgalactosaminyl({beta}1{r arrow} 4)-(N-acetylneuraminyl({alpha}2{r arrow} 3))galactosyl({beta}1 {r arrow} 4)glucosyl({beta}1 {r arrow} 1)ceramide (GM1) family. Its intimate association with receptor protein implies a key role for ganglioside in the structure and function of the TSH-R.

  14. Recovery from Experimental Parkinsonism in Primates with GM1 Ganglioside Treatment

    NASA Astrophysics Data System (ADS)

    Schneider, J. S.; Pope, Anne; Simpson, Kimberly; Taggart, James; Smith, M. G.; Distefano, L.

    1992-05-01

    A parkinsonian syndrome can be produced in nonhuman primates by administration of the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Parkinsonian-like symptoms induced acutely by MPTP were ameliorated after treatment with GM1 ganglioside, a substance shown to have neurotrophic effects on the damaged dopamine system in rodents. Treatment with GM1 ganglioside also increased striatal dopamine and metabolite levels and enhanced the dopaminergic innervation of the striatum as demonstrated by tyrosine hydroxylase immunohistochemistry. These results suggest that GM1 ganglioside may hold promise as a therapeutic agent for the treatment of Parkinson's disease.

  15. Gd3+ and Calcium Sensitive, Sodium Leak Currents Are Features of Weak Membrane-Glass Seals in Patch Clamp Recordings

    PubMed Central

    Chemin, Jean; Monteil, Arnaud; Spafford, J. David

    2014-01-01

    The properties of leaky patch currents in whole cell recording of HEK-293T cells were examined as a means to separate these control currents from expressed sodium and calcium leak channel currents from snail NALCN leak channels possessing both sodium (EKEE) and calcium (EEEE) selectivity filters. Leak currents were generated by the weakening of gigaohm patch seals by artificial membrane rupture using the ZAP function on the patch clamp amplifier. Surprisingly, we found that leak currents generated from the weakened membrane/glass seal can be surprisingly stable and exhibit behavior that is consistent with a sodium leak current derived from an expressible channel. Leaky patch currents differing by 10 fold in size were similarly reduced in size when external sodium ions were replaced with the large monovalent ion NMDG+. Leaky patch currents increased when external Ca2+ (1.2 mM) was lowered to 0.1 mM and were inhibited (>40% to >90%) with 10 µM Gd3+, 100 µM La3+, 1 mM Co2+ or 1 mM Cd2+. Leaky patch currents were relatively insensitive (<30%) to 1 mM Ni2+ and exhibited a variable amount of block with 1 mM verapamil and were insensitive to 100 µM mibefradil or 100 µM nifedipine. We hypothesize that the rapid changes in leak current size in response to changing external cations or drugs relates to their influences on the membrane seal adherence and the electro-osmotic flow of mobile cations channeling in crevices of a particular pore size in the interface between the negatively charged patch electrode and the lipid membrane. Observed sodium leak conductance currents in weak patch seals are reproducible between the electrode glass interface with cell membranes, artificial lipid or Sylgard rubber. PMID:24945283

  16. Magnetic behavior of Gd3Ru4Al12, a layered compound with distorted kagomé net

    NASA Astrophysics Data System (ADS)

    Chandragiri, Venkatesh; Iyer, Kartik K.; Sampathkumaran, E. V.

    2016-07-01

    The magnetic behavior of the compound, Gd3Ru4Al12, which was reported about two decades ago to crystallize in a hexagonal structure (space group P63/mmc), has not been investigated in the past literature despite interesting structural features (that is, magnetic layers and triangular as well as kagomé-lattice features favoring frustrated magnetism) characterizing this compound. We report here the results of studies of magnetization, heat capacity and magnetoresistance in the temperature range T  =  1.8-300 K. The results establish that there is a long-range magnetic order of antiferromagnetic type below (T N  =) 18.5 K, despite a much larger value (~80 K) of paramagnetic Curie temperature with a positive sign characteristic of ferromagnetic interaction. We attribute this to geometric frustration. The most interesting finding is that there is an additional magnetic anomaly below ~55 K before the onset of long-range order in the magnetic susceptibility data. Concurrent with this observation, the sign of isothermal change in entropy, ΔS  =  S(0)  -  S(H), where H is the externally applied magnetic field, remains positive above T N, with a broad peak. This observation indicates the presence of ferromagnetic clusters before the onset of long-range magnetic order. Thus, this compound may serve as an example of a situation in which magnetic frustration due to geometrical reasons faces competition from such magnetic precursor effects. There is also a reversal of the sign of  -ΔS in the curves for lower final fields (H  <  30 kOe) on entering the magnetically ordered state consistent with the entrance to an antiferromagetic state. The magnetoresistance behavior is consistent with the above conclusions.

  17. Magnetic behavior of Gd3Ru4Al12, a layered compound with distorted kagomé net.

    PubMed

    Chandragiri, Venkatesh; Iyer, Kartik K; Sampathkumaran, E V

    2016-05-27

    The magnetic behavior of the compound, Gd3Ru4Al12, which was reported about two decades ago to crystallize in a hexagonal structure (space group P63/mmc), has not been investigated in the past literature despite interesting structural features (that is, magnetic layers and triangular as well as kagomé-lattice features favoring frustrated magnetism) characterizing this compound. We report here the results of studies of magnetization, heat capacity and magnetoresistance in the temperature range T  =  1.8-300 K. The results establish that there is a long-range magnetic order of antiferromagnetic type below (T N  =) 18.5 K, despite a much larger value (~80 K) of paramagnetic Curie temperature with a positive sign characteristic of ferromagnetic interaction. We attribute this to geometric frustration. The most interesting finding is that there is an additional magnetic anomaly below ~55 K before the onset of long-range order in the magnetic susceptibility data. Concurrent with this observation, the sign of isothermal change in entropy, ΔS  =  S(0)  -  S(H), where H is the externally applied magnetic field, remains positive above T N, with a broad peak. This observation indicates the presence of ferromagnetic clusters before the onset of long-range magnetic order. Thus, this compound may serve as an example of a situation in which magnetic frustration due to geometrical reasons faces competition from such magnetic precursor effects. There is also a reversal of the sign of  -ΔS in the curves for lower final fields (H  <  30 kOe) on entering the magnetically ordered state consistent with the entrance to an antiferromagetic state. The magnetoresistance behavior is consistent with the above conclusions.

  18. Effects of doping concentration and co-doping with cerium on the luminescence properties of Gd3Ga5O12:Cr3+ for thermometry applications

    NASA Astrophysics Data System (ADS)

    Pareja, Jhon; Litterscheid, Christian; Molina, Alejandro; Albert, Barbara; Kaiser, Bernhard; Dreizler, Andreas

    2015-09-01

    The accuracy of surface temperature measurements using thermographic phosphors relies on an extensive knowledge of the temperature-dependent properties of the phosphor. This paper addresses the effects of doping concentration and co-doping with cerium on the luminescence properties of the Gd3Ga5O12:Cr3+ phosphor. High-crystallinity Gd3Ga5O12:Cr3+,Ce3+ powder samples (GGG:Cr,Ce) with different Cr3+ and Ce3+ concentrations were synthesized, and their luminescence spectra as well as their decay lifetime properties were characterized after UV laser excitation. Results revealed that the concentration quenching decreases the luminescence lifetime at concentrations above 0.5 mol% Cr3+ while the emission spectrum remains independent of the Cr3+ concentration. Co-doping with small amounts of Ce3+ improves the temperature-dependent luminescence characteristics by reducing the afterglow and producing fairly mono-exponential luminescence decays without changing the lifetime.

  19. Studies of the spin-Hamiltonian parameters and defect structures for Gd3+ ions in zircon-structure silicates MSiO4 (M=Zr, Hf, Th).

    PubMed

    Yang, Wei-Qing; Zheng, Wen-Chen

    2011-09-01

    The spin-Hamiltonian parameters (g factors g∥, g⊥ and zero-field splittings b2(0), b4(0), b4(4), b6(0), b6(4)) for 4f7 ion Gd3+ at the tetragonal M4+ site of zircon-structure silicates MSiO4 (M=Zr, Hf, Th) are calculated from a diagonalization (of energy matrix) method. The Hamiltonian concerning this energy matrix contains the free-ion, crystal-field interaction and Zeeman interaction terms and the 56×56 energy matrix is constructed by considering the ground multiplet 8S7/2 and the excited multiplets 6L7/2 (L=P, D, F, G, H, I). The defect structures of Gd3+ centers in the three MSiO4 crystals are yielded from the calculation. The results are discussed.

  20. Variability in brain ganglioside content and composition of endothermic mammals, heterothermic hibernators and ectothermic fishes.

    PubMed

    Kappel, T; Hilbig, R; Rahmann, H

    1993-06-01

    Content and composition of brain gangliosides were compared among endothermic mammals, heterothermic hibernators and ectothermic fishes from habitats with extreme ambient temperatures (tropic vs. antarctic waters). In general the content of brain gangliosides in fishes is significantly lower and exhibits a greater variability than in mammals. The composition of brain gangliosides was investigated using both one- and two-dimensional High Performance Thin Layer Chromatography (HPTLC). Both techniques showed a remarkable increase in the number of individual ganglioside fractions and an additional increase of higher polar fractions in fishes as compared with mammals. The 2D-HPTLC revealed a significant decrease in the relative proportion of alkali-labile gangliosides in the course of evolution from fish to mammals. Moreover this decrease in alkali-lability is correlated with the state of thermal adaptation (antarctic fishes, 53-66%; tropical cichlid fish, 35%). These results provide additional evidence for the notion that the extremely high polarity of brain gangliosides, especially of cold-blooded vertebrates, reflects a very efficient mechanism on the molecular level to keep the neuronal membrane functional under low temperature conditions.

  1. The Protective Effect of Gangliosides on Lead (Pb)-Induced Neurotoxicity Is Mediated by Autophagic Pathways.

    PubMed

    Meng, Hongtao; Wang, Lan; He, Junhong; Wang, Zhufeng

    2016-03-25

    Lead (Pb) is a ubiquitous environmental and industrial pollutant and can affect intelligence development and the learning ability and memory of children. Therefore, necessary measures should be taken to protect the central nervous system (CNS) from Pb toxicity. Gangliosides are sialic acid-containing glycosphingolipids that are constituents of mammalian cell membranes and are more abundantly expressed in the CNS. Studies have shown that gangliosides constitute a useful tool in the attempt to promote functional recovery of CNS and can reverse Pb-induced impairments of synaptic plasticity in rats. However, the detailed mechanisms have yet to be fully understood. In our present study, we tried to investigate the role of gangliosides in Pb-induced injury in hippocampus neurons and to further confirm the detailed mechanism. Our results show that Pb-induced injuries in the spatial reference memory were associated with a reduction of cell viability and cell apoptosis, and treatment with gangliosides markedly ameliorated the Pb-induced injury by inhibition of apoptosis action. Gangliosides further attenuated Pb-induced the abnormal autophagic process by regulation of mTOR pathways. In summary, our study establishes the efficacy of gangliosides as neuroprotective agents and provides a strong rationale for further studies on the underlying mechanisms of their neuroprotective functions.

  2. Impaired Levels of Gangliosides in the Corpus Callosum of Huntington Disease Animal Models

    PubMed Central

    Di Pardo, Alba; Amico, Enrico; Maglione, Vittorio

    2016-01-01

    Huntington Disease (HD) is a genetic neurodegenerative disorder characterized by broad types of cellular and molecular dysfunctions that may affect both neuronal and non-neuronal cell populations. Among all the molecular mechanisms underlying the complex pathogenesis of the disease, alteration of sphingolipids has been identified as one of the most important determinants in the last years. In the present study, besides the purpose of further confirming the evidence of perturbed metabolism of gangliosides GM1, GD1a, and GT1b the most abundant cerebral glycosphingolipids, in the striatal and cortical tissues of HD transgenic mice, we aimed to test the hypothesis that abnormal levels of these lipids may be found also in the corpus callosum white matter, a ganglioside-enriched brain region described being dysfunctional early in the disease. Semi-quantitative analysis of GM1, GD1a, and GT1b content indicated that ganglioside metabolism is a common feature in two different HD animal models (YAC128 and R6/2 mice) and importantly, demonstrated that levels of these gangliosides were significantly reduced in the corpus callosum white matter of both models starting from the early stages of the disease. Besides corroborating the evidence of aberrant ganglioside metabolism in HD, here, we found out for the first time, that ganglioside dysfunction is an early event in HD models and it may potentially represent a critical molecular change influencing the pathogenesis of the disease. PMID:27766070

  3. Cloning and transcriptional regulation of genes responsible for synthesis of gangliosides.

    PubMed

    Zeng, Guichao; Yu, Robert K

    2008-04-01

    Ganglioside synthases are glycosyltransferases involved in the biosynthesis of glycoconjugates. A number of ganglioside synthase genes have been cloned and characterized. They are classified into different families of glycosyltransferases based on similarities of their amino acid sequences. Tissue-specific expression of these genes has been analyzed by hybridization using cDNA fragments. Enzymatic characterization with the expressed recombinant enzymes showed these enzymes differ in their donor and acceptor substrate specificities and other biochemical parameters. In vitro enzymatic analysis also showed that one linkage can be synthesized by multiple enzymes and one enzyme may be responsible for synthesis of multiple gangliosides. Following the cloning of the ganglioside synthase genes, the promoters of the key synthase genes in the ganglioside biosynthetic pathway have been cloned and analyzed. All of the promoters are TATA-less, lacking a CCAAT box but containing GC-rich boxes, characteristic of the house-keeping genes, although transcription of ganglioside synthase genes is subject to complex developmental and tissue-specific regulation. A set of cis-acting elements and transcription factors, including Sp1, AP2, and CREB, function in the proximal promoters. Negative-regulatory regions have also been defined in most of the promoters. We present here an overview of these genes and their transcriptional regulation.

  4. Effect of Mg2+ ions co-doping on timing performance and radiation tolerance of Cerium doped Gd3Al2Ga3O12 crystals

    NASA Astrophysics Data System (ADS)

    Lucchini, M. T.; Babin, V.; Bohacek, P.; Gundacker, S.; Kamada, K.; Nikl, M.; Petrosyan, A.; Yoshikawa, A.; Auffray, E.

    2016-04-01

    Inorganic scintillators with high density and high light yield are of major interest for applications in medical imaging and high energy physics detectors. In this work, the optical and scintillation properties of Mg co-doped Ce:Gd3Al2Ga3O12 crystals, grown using Czochralski technique, have been investigated and compared with Ce:Gd3Al2Ga3O12 ones prepared with identical technology. Improvements in the timing performance of the Mg co-doped samples with respect to Ce:Gd3Al2Ga3O12 ones have been measured, namely a substantial shortening of the rise time and scintillation decay components and lower afterglow were achieved. In particular, a significantly better coincidence time resolution of 233 ps FWHM, being a fundamental parameter for TOF-PET devices, has been observed in Mg co-doped crystals. The samples have also shown a good radiation tolerance under high doses of γ-rays, making them suitable candidates for applications in harsh radiation environments, such as detectors at future collider experiments.

  5. The Gadolinium (Gd3+) and Tin (Sn4+) Co-doped BiFeO3 Nanoparticles as New Solar Light Active Photocatalyst

    PubMed Central

    Irfan, Syed; Rizwan, Syed; Shen, Yang; Li, Liangliang; Asfandiyar, A; Butt, Sajid; Nan, Ce-Wen

    2017-01-01

    The process of photocatalysis is appealing to huge interest motivated by the great promise of addressing current energy and environmental issues through converting solar light directly into chemical energy. However, an efficient solar energy harvesting for photocatalysis remains a critical challenge. Here, we reported a new full solar spectrum driven photocatalyst by co-doping of Gd3+ and Sn4+ into A and B-sites of BiFeO3 simultaneously. The co-doping of Gd3+ and Sn4+ played a key role in hampering the recombination of electron-hole pairs and shifted the band-gap of BiFeO3 from 2.10 eV to 2.03 eV. The Brunauer-Emmett-Teller (BET) measurement confirmed that the co-doping of Gd3+ and Sn4+ into BiFeO3 increased the surface area and porosity, and thus the photocatalytic activity of the Bi0.90Gd0.10Fe0.95Sn0.05O3 system was significantly improved. Our work proposed a new photocatalyst that could degrade various organic dyes like Congo red, Methylene blue, and Methyl violet under irradiation with different light wavelengths and gave guidance for designing more efficient photocatalysts. PMID:28195198

  6. The Gadolinium (Gd3+) and Tin (Sn4+) Co-doped BiFeO3 Nanoparticles as New Solar Light Active Photocatalyst

    NASA Astrophysics Data System (ADS)

    Irfan, Syed; Rizwan, Syed; Shen, Yang; Li, Liangliang; Asfandiyar; Butt, Sajid; Nan, Ce-Wen

    2017-02-01

    The process of photocatalysis is appealing to huge interest motivated by the great promise of addressing current energy and environmental issues through converting solar light directly into chemical energy. However, an efficient solar energy harvesting for photocatalysis remains a critical challenge. Here, we reported a new full solar spectrum driven photocatalyst by co-doping of Gd3+ and Sn4+ into A and B-sites of BiFeO3 simultaneously. The co-doping of Gd3+ and Sn4+ played a key role in hampering the recombination of electron-hole pairs and shifted the band-gap of BiFeO3 from 2.10 eV to 2.03 eV. The Brunauer-Emmett-Teller (BET) measurement confirmed that the co-doping of Gd3+ and Sn4+ into BiFeO3 increased the surface area and porosity, and thus the photocatalytic activity of the Bi0.90Gd0.10Fe0.95Sn0.05O3 system was significantly improved. Our work proposed a new photocatalyst that could degrade various organic dyes like Congo red, Methylene blue, and Methyl violet under irradiation with different light wavelengths and gave guidance for designing more efficient photocatalysts.

  7. Facile preparation of Gd3+ doped carbon quantum dots: Photoluminescence materials with magnetic resonance response as magnetic resonance/fluorescence bimodal probes

    NASA Astrophysics Data System (ADS)

    Ren, X. Y.; Yuan, X. X.; Wang, Y. P.; Liu, C. L.; Qin, Y.; Guo, L. P.; Liu, L. H.

    2016-07-01

    There are a few bimodal molecular imaging probes constructed by gadolinium (3+) ions in combination with carbon quantum dots (CQDs), and the reported ones show such obvious drawbacks as low luminous efficiency and weak MRI contrast. In the paper, a kind of CQDs photoluminescence materials with magnetic resonance response was prepared by hydrothermal method and employing gadopentetate monomeglumine (GdPM) as a precusor. Here, the GdPM plays a role of not only carbon source, but also gadolinium (3+) sources. When the GdPM aqueous solution with a concentration of 4 mg mL-1 was pyrolyzed under 220 °C and 2.0 MPa for 8 h, an optimal CQDs was obtained which are doped with gadolinium (3+) ions in both chelates and Gd2O3 (named as Gd3+-CQDs). The average diameter of the Gd3+-CQDs is about 1.6 nm, which show a high photoluminescence quantum yield of 7.1%, as well as high longitudinal relaxivity (r1) of 9.87 mM-1 s-1. And owing to the unconspicuous cell toxicity, the Gd3+-CQDs show big possibility for clinical application in magnetic resonance/fluorescence bimodal molecular imaging.

  8. EPR detected polarization transfer between Gd3+ and protons at low temperature and 3.3 T: The first step of dynamic nuclear polarization

    NASA Astrophysics Data System (ADS)

    Nagarajan, Vijayasarathi; Hovav, Yonatan; Feintuch, Akiva; Vega, Shimon; Goldfarb, Daniella

    2010-06-01

    Electron-electron double resonance pulsed electron paramagnetic resonance (EPR) at 95 GHz (3.3 T) is used to follow the dynamics of the electron spin polarization during the first stages of dynamic nuclear polarization in solids. The experiments were performed on a frozen solution of Gd+3 (S =7/2) in water/glycerol. Focusing on the central |-1/2⟩→|+1/2⟩ transition we measured the polarization transfer from the Gd3+ electron spin to the adjacent H1 protons. The dependence of the echo detected EPR signal on the length of the microwave irradiation at the EPR "forbidden" transition corresponding to an electron and a proton spin flip is measured for different powers, showing dynamics on the microsecond to millisecond time scales. A theoretical model based on the spin density matrix formalism is suggested to account for this dynamics. The central transition of the Gd3+ ion is considered as an effective S =1/2 system and is coupled to H1 (I =1/2) nuclei. Simulations based on a single electron-single nucleus four level system are shown to deviate from the experimental results and an alternative approach taking into account the more realistic multinuclei picture is shown to agree qualitatively with the experiments.

  9. Pulse shape discrimination properties of Gd3Ga3Al2O12:Ce,B single crystal in comparison with CsI:Tl

    NASA Astrophysics Data System (ADS)

    Rawat, S.; Tyagi, Mohit; Netrakanti, P. K.; Kashyap, V. K. S.; Mitra, A.; Singh, A. K.; Desai, D. G.; Kumar, G. Anil; Gadkari, S. C.

    2016-12-01

    Single crystals of Gd3Ga3Al2O12:Ce,B and CsI:Tl were grown by Czochralski and Bridgman techniques, respectively. While both the crystals exhibited similar emission at about 550 nm, their scintillation decay times showed significantly different characteristics. The average scintillation decay time of Gd3Ga3Al2O12:Ce,B crystal was found to be about 284 ns for alpha excitation compared to 108 ns measured for a gamma source. On the other hand in CsI:Tl crystals, the alpha excitation resulted in a lower average decay time of 600 ns compared to 1200 ns with gamma excitation. Their pulse shape discrimination (PSD) for gamma and alpha radiations were studied by coupling the scintillators with photomultiplier tube or SiPM and employing an advanced digitizer as well as a conventional zero-crossing setup. In spite of having a poor α/γ light yield ratio, the PSD figure of merit and the difference of zero-crossing time in Gd3Ga3Al2O12:Ce,B crystals were found to be superior in comparison to CsI:Tl crystals.

  10. W-band orientation selective DEER measurements on a Gd3+/nitroxide mixed-labeled protein dimer with a dual mode cavity

    NASA Astrophysics Data System (ADS)

    Kaminker, Ilia; Tkach, Igor; Manukovsky, Nurit; Huber, Thomas; Yagi, Hiromasa; Otting, Gottfried; Bennati, Marina; Goldfarb, Daniella

    2013-02-01

    Double electron-electron resonance (DEER) at W-band (95 GHz) was applied to measure the distance between a pair of nitroxide and Gd3+ chelate spin labels, about 6 nm apart, in a homodimer of the protein ERp29. While high-field DEER measurements on systems with such mixed labels can be highly attractive in terms of sensitivity and the potential to access long distances, a major difficulty arises from the large frequency spacing (about 700 MHz) between the narrow, intense signal of the Gd3+ central transition and the nitroxide signal. This is particularly problematic when using standard single-mode cavities. Here we show that a novel dual-mode cavity that matches this large frequency separation dramatically increases the sensitivity of DEER measurements, allowing evolution times as long as 12 μs in a protein. This opens the possibility of accessing distances of 8 nm and longer. In addition, orientation selection can be resolved and analyzed, thus providing additional structural information. In the case of W-band DEER on a Gd3+-nitroxide pair, only two angles and their distributions have to be determined, which is a much simpler problem to solve than the five angles and their distributions associated with two nitroxide spin labels.

  11. The Gadolinium (Gd(3+)) and Tin (Sn(4+)) Co-doped BiFeO3 Nanoparticles as New Solar Light Active Photocatalyst.

    PubMed

    Irfan, Syed; Rizwan, Syed; Shen, Yang; Li, Liangliang; Asfandiyar; Butt, Sajid; Nan, Ce-Wen

    2017-02-14

    The process of photocatalysis is appealing to huge interest motivated by the great promise of addressing current energy and environmental issues through converting solar light directly into chemical energy. However, an efficient solar energy harvesting for photocatalysis remains a critical challenge. Here, we reported a new full solar spectrum driven photocatalyst by co-doping of Gd(3+) and Sn(4+) into A and B-sites of BiFeO3 simultaneously. The co-doping of Gd(3+) and Sn(4+) played a key role in hampering the recombination of electron-hole pairs and shifted the band-gap of BiFeO3 from 2.10 eV to 2.03 eV. The Brunauer-Emmett-Teller (BET) measurement confirmed that the co-doping of Gd(3+) and Sn(4+) into BiFeO3 increased the surface area and porosity, and thus the photocatalytic activity of the Bi0.90Gd0.10Fe0.95Sn0.05O3 system was significantly improved. Our work proposed a new photocatalyst that could degrade various organic dyes like Congo red, Methylene blue, and Methyl violet under irradiation with different light wavelengths and gave guidance for designing more efficient photocatalysts.

  12. Enhanced UVB emission and analysis of chemical states of Ca5(PO4)3OH:Gd3+,Pr3+ phosphor prepared by co-precipitation

    NASA Astrophysics Data System (ADS)

    Mokoena, P. P.; Nagpure, I. M.; Kumar, Vinay; Kroon, R. E.; Olivier, E. J.; Neethling, J. H.; Swart, H. C.; Ntwaeaborwa, O. M.

    2014-08-01

    Hydroxyapatite (Ca5(PO4)3OH) is a well-known bioceramic material used in medical applications because of its ability to form direct chemical bonds with living tissues. This mineral is currently used as a host for rare-earth ions (e.g. Gd3+, Pr3+, Tb3+, etc.) to prepare phosphors that can be used in light emitting devices of different types. In this study Ca5(PO4)3OH:Gd3+,Pr3+ phosphors were prepared by the co-precipitation method and were characterised by x-ray diffraction, x-ray photoelectron spectroscopy, scanning electron microscopy, high resolution transmission electron microscopy, energy dispersive x-ray spectroscopy and photoluminescence spectroscopy. The x-ray diffraction pattern was consistent with the hexagonal phase of Ca5(PO4)3OH referenced in JCPDS card number 73-0293. The x-ray photoelectron spectroscopy data indicated that Ca2+ occupied two different lattice sites, referred to as Ca1 and Ca2. The photoluminescence data exhibited a narrowband emission located at 313 nm, which is associated with the 6P7/2→8S7/2 transition of the Gd3+ ion. This emission is classified as ultraviolet B and it is suitable for use in phototherapy lamps to treat various skin diseases. The photoluminescence intensity of the 313 nm emission was enhanced considerably by Pr3+ co-doping.

  13. Combination of ESI and MALDI mass spectrometry for qualitative, semi-quantitative and in situ analysis of gangliosides in brain

    PubMed Central

    Zhang, Yangyang; Wang, Jun; Liu, Jian’an; Han, Juanjuan; Xiong, Shaoxiang; Yong, Weidong; Zhao, Zhenwen

    2016-01-01

    Gangliosides are a family of complex lipids that are abundant in the brain. There is no doubt the investigations about the distribution of gangliosides in brian and the relationship between gangliosides and Alzheimer’s disease is profound. However, these investigations are full of challenges due to the structural complexity of gangliosides. In this work, the method for efficient extraction and enrichment of gangliosides from brain was established. Moreover, the distribution of gangliosides in brain was obtained by matrix-assisted laser desorption ionization (MALDI) mass spectrometry imaging (MSI). It was found that 3-aminoquinoline (3-AQ) as matrix was well-suited for MALDI MS analysis of gangliosides in negative ion mode. In addition, the pretreatment by ethanol (EtOH) cleaning brain section and the addition of ammonium formate greatly improved the MS signal of gangliosides in the brain section when MALDI MSI analysis was employed. The distribution of ganliosides in cerebral cortex, hippocampus and cerebellum was respectively acquired by electrospray ionization (ESI) MS and MALDI MSI, and the data were compared for reliability evaluation of MALDI MSI. Further, applying MALDI MSI technology, the distribution of gangliosides in amyloid precursor protein transgenic mouse brain was obtained, which may provide a new insight for bioresearch of Alzheimer’s disease (AD). PMID:27142336

  14. Proton NMR study of spin dynamics in the magnetic organic chains M (hfac)3 NITEt (M =Eu3 +,Gd3 + )

    NASA Astrophysics Data System (ADS)

    Mariani, M.; Lascialfari, A.; Caneschi, A.; Ammannato, L.; Gatteschi, D.; Rettori, A.; Pini, M. G.; Cucci, C.; Borsa, F.

    2016-04-01

    In this work, we present a nuclear magnetic resonance (NMR) study of the spin dynamics in the rare-earth-based low-dimensional molecular magnetic chains Eu (hfac) 3NITEt and Gd (hfac) 3NITEt (in short, Eu-Et and Gd-Et). Although both samples are based on the same chemical building block, [(hfac) 3NITEt ] , their magnetic properties change dramatically when the Eu3 + ion, which is nonmagnetic at low temperatures, is substituted by the magnetic Gd3 + ion. The present proton NMR investigation shows that, down to the lowest investigated temperature (T =1.5 K for Gd-Et and T =3 K for Eu-Et), the Eu-Et chain behaves as a one-dimensional Heisenberg model with antiferromagnetic exchange coupling (J =-20 K) between s =1 /2 organic radicals, and has a T -independent exchange frequency (ωe=2.6 ×1012 rad/s). In the Gd-Et chain, in contrast, a competition arises between nearest-neighbor ferromagnetic coupling and next-nearest-neighbor antiferromagnetic coupling; moreover, two phase transitions have previously been found, in agreement with Villain's conjecture: a first transition, at T0=2.2 K, from a high temperature paramagnetic phase to a chiral spin liquid phase, and a second transition, at TN=1.9 K, to a three-dimensional helical spin solid phase. Contrary to the Eu-Et chain (whose three-dimensional ordering temperature is estimated to insurge at very low, TN≈0.3 K), critical spin dynamics effects have been measured in the Gd-Et chain on approaching TN=1.9 K: namely, a divergence of the proton nuclear spin-lattice relaxation rate 1 /T1 , which in turn produces a sudden wipe-out of the NMR signal in a very narrow (Δ T ˜0.04 K) temperature range above TN. Below TN, an inhomogeneous broadening of the NMR line indicates a complete spin freezing. At T0=2.2 K, instead, such critical effects are not observed because NMR measurements probe the two-spin correlation function, while the chiral spin liquid phase transition is associated with a divergence of the four

  15. Brain gangliosides: functional ligands for myelin stability and the control of nerve regeneration.

    PubMed

    Vyas, A A; Schnaar, R L

    2001-07-01

    Gangliosides, sialylated glycosphingolipids which are the predominant glycans on vertebrate nerve cell surfaces, are emerging as components of membrane rafts, where they can mediate important physiological functions. Myelin associated glycoprotein (MAG), a minor constituent of myelin, is a sialic acid binding lectin with two established physiological functions: it is involved in myelin-axon stability and cytoarchitecture, and controls nerve regeneration. MAG is found selectively on the myelin membranes directly apposed to the axon surface, where it has been proposed to mediate myelin-axon interactions. Although the nerve cell surface ligands for MAG remain to be established, evidence supports a functional role for sialylated glycoconjugates. Here we review recent studies that reflect on the role of gangliosides, sialylated glycosphingolipids, as functional MAG ligands. MAG binds to gangliosides with the terminal sequence 'NeuAc alpha 3Gal beta 3GalNAc' which is found on the major nerve gangliosides GD1a and GT1b. Gangliosides lacking that terminus (e.g., GM1 or GD1b), or having any biochemical modification of the terminal NeuAc residue fail to support MAG binding. Genetically engineered mice lacking the GalNAc transferase required for biosynthesis of the 'NeuAc alpha 3Gal beta 3GalNAc' terminus have grossly impaired myelination and progressive neurodegeneration. Notably the MAG level in these animals is dysregulated. Furthermore, removal of NeuAc residues from nerve cells reverses MAG-mediated inhibition of neuritogenesis, and neurons from mice lacking the 'NeuAc alpha 3 Gal beta 3GalNAc' terminus have an attenuated response to MAG. Cross-linking nerve cell surface gangliosides can mimic MAG-mediated inhibition of nerve regeneration. Taken together these observations implicate gangliosides as functional MAG ligands.

  16. Fibrillar organization of fibronectin is expressed coordinately with cell surface gangliosides in a variant murine fibroblast

    PubMed Central

    1986-01-01

    NCTC 2071A cells, a line of transformed murine fibroblasts, grow in serum-free medium, are deficient in gangliosides, synthesize fibronectin, but do not retain and organize it on the cell surface. When the cells are exposed to exogenous gangliosides, fibrillar strands of fibronectin become attached to the cell surface. A morphologically distinct variant of NCTC 2071A cells was observed to both retain cell surface fibronectin and organize it into a fibrillar network when the cells were stained with anti-fibronectin antibodies and a fluorescent second antibody. A revertant cell type appeared to resemble the parental NCTC 2071A cells in terms of morphology and fibronectin organization. All three cell types were subjected to mild NaIO4 oxidation and reduction with KB3H4 of very high specific radioactivity in order to label the sialic acid residues of surface gangliosides. The variant had much more surface gangliosides than the parental, particularly more complex gangliosides corresponding to GM1 and GD1a. The surface gangliosides of the revertant were intermediate between the parental and the variant. By using sialidase, which hydrolyzes GD1a to GM1, and 125I-labeled cholera toxin, which binds specifically to GM1, the identity and levels of these gangliosides were confirmed in the three cell types. When variant cells were exposed to sialidase for 2 d, there appeared to be little change in fibronectin organization. Concomitant treatment of the cells with the B subunit of cholera toxin, which bound to all the surface GM1 including that generated by the sialidase, however, eliminated the fibrillar network of fibronectin. In addition, exposure of the variant cells to a 70,000-mol-wt fragment of fibronectin, which lacks the cell attachment domain but contains a matrix assembly domain, inhibited the formation of fibers. Finally, all three cell types were assayed for their ability to attach to and spread on fibronectin-coated surfaces; no significant differences were found

  17. Localization and imaging of gangliosides in mouse brain tissue sections by laserspray ionization inlet[S

    PubMed Central

    Richards, Alicia L.; Lietz, Christopher B.; Wager-Miller, James; Mackie, Ken; Trimpin, Sarah

    2012-01-01

    A new ionization method for the analysis of fragile gangliosides without undesired fragmentation or salt adduction is presented. In laserspray ionization inlet (LSII), the matrix/analyte sample is ablated at atmospheric pressure, and ionization takes place in the ion transfer capillary of the mass spectrometer inlet by a process that is independent of a laser wavelength or voltage. The softness of LSII allows the identification of gangliosides up to GQ1 with negligible sialic acid loss. This is of importance to the field of MS imaging, as undesired fragmentation has made it difficult to accurately map the spatial distribution of fragile ganglioside lipids in tissue. Proof-of-principle structural characterization of endogenous gangliosides using MSn fragmentation of multiply charged negative ions on a LTQ Velos and subsequent imaging of the GD1 ganglioside is demonstrated. This is the first report of multiply charged negative ions using inlet ionization. We find that GD1 is detected at higher levels in the mouse cortex and hippocampus compared with the thalamus. In LSII with the laser aligned in transmission geometry relative to the inlet, images were obtained in approximately 60 min using an inexpensive nitrogen laser. PMID:22262808

  18. Oligosaccharide-specific receptors for gangliosides in the central nervous system

    SciTech Connect

    Tiemeyer, M.J.

    1989-01-01

    Synthetic ganglioside-derivatized proteins were prepared, radiolabeled, and used as ligands to search for specific receptors on rat brain membranes. Chemical derivatization schemes were designed to covalently link gangliosides (specifically, G{sub T1b}) to bovine serum albumin (BSA) via their ceramide portions leaving the glycolipid oligosaccharides intact and limiting the ability of the ganglioside moiety to interact with brain membranes non-specifically by insertion or hydrophobic adsorption. Following characterization and tyrosine-radioiodination, {sup 125}I-(G{sub T1b}){sub 4} BSA (BSA derivatized with 4 G{sub T1b} moieties/protein molecule), revealed a high affinity and saturable binding site on rat brain membranes. Pretreatment of brain membranes with low concentrations of trypsin blocked binding, consistent with the presence of a proteinaceous ganglioside-receptor. The most potent lipid inhibitors of {sup 125}I-(G{sub T1b}){sub 4}BSA binding were the gangliosides G{sub T1b}, G{sub D1b}, and G{sub Q1b} which share common structural features in their oligosaccharide portions; maximal inhibitory potency required a full length gangliotetraose oligosaccharide core and {alpha}2-8 linked sialic acid.

  19. Raft-based interactions of gangliosides with a GPI-anchored receptor.

    PubMed

    Komura, Naoko; Suzuki, Kenichi G N; Ando, Hiromune; Konishi, Miku; Koikeda, Machi; Imamura, Akihiro; Chadda, Rahul; Fujiwara, Takahiro K; Tsuboi, Hisae; Sheng, Ren; Cho, Wonhwa; Furukawa, Koichi; Furukawa, Keiko; Yamauchi, Yoshio; Ishida, Hideharu; Kusumi, Akihiro; Kiso, Makoto

    2016-06-01

    Gangliosides, glycosphingolipids containing one or more sialic acid(s) in the glyco-chain, are involved in various important physiological and pathological processes in the plasma membrane. However, their exact functions are poorly understood, primarily because of the scarcity of suitable fluorescent ganglioside analogs. Here, we developed methods for systematically synthesizing analogs that behave like their native counterparts in regard to partitioning into raft-related membrane domains or preparations. Single-fluorescent-molecule imaging in the live-cell plasma membrane revealed the clear but transient colocalization and codiffusion of fluorescent ganglioside analogs with a fluorescently labeled glycosylphosphatidylinisotol (GPI)-anchored protein, human CD59, with lifetimes of 12 ms for CD59 monomers, 40 ms for CD59's transient homodimer rafts in quiescent cells, and 48 ms for engaged-CD59-cluster rafts, in cholesterol- and GPI-anchoring-dependent manners. The ganglioside molecules were always mobile in quiescent cells. These results show that gangliosides continually and dynamically exchange between raft domains and the bulk domain, indicating that raft domains are dynamic entities.

  20. Partial synthesis of ganglioside and lysoganglioside lipoforms as internal standards for MS quantification

    PubMed Central

    Gantner, Martin; Schwarzmann, Günter; Sandhoff, Konrad; Kolter, Thomas

    2014-01-01

    Within recent years, ganglioside patterns have been increasingly analyzed by MS. However, internal standards for calibration are only available for gangliosides GM1, GM2, and GM3. For this reason, we prepared homologous internal standards bearing nonnatural fatty acids of the major mammalian brain gangliosides GM1, GD1a, GD1b, GT1b, and GQ1b, and of the tumor-associated gangliosides GM2 and GD2. The fatty acid moieties were incorporated after selective chemical or enzymatic deacylation of bovine brain gangliosides. For modification of the sphingoid bases, we developed a new synthetic method based on olefin cross metathesis. This method was used for the preparation of a lyso-GM1 and a lyso-GM2 standard. The total yield of this method was 8.7% for the synthesis of d17:1-lyso-GM1 from d20:1/18:0-GM1 in four steps. The title compounds are currently used as calibration substances for MS quantification and are also suitable for functional studies. PMID:25341943

  1. Detection of Sendai virus receptor, the ganglioside GDla, in target tissue (mouse lung)

    SciTech Connect

    Markwell, M.A.K.; Sato, E.

    1986-05-01

    Previously the authors had shown that the gangliosides GDla, GTlb, and GQlb derived from brain function as receptors for the paramyxovirus Sendai virus by their ability to induce infection when incubated with receptor-deficient cells. Analyses of MDBK, HeLa, and MDCK cells in culture demonstrated that these putative receptors were present in host cells in the quantities required for infection. The primary site of infection for Sendai virus in the whole animal is the respiratory tract, culminating in the lung. Therefore, the ganglioside content of this target organ was analyzed to determine the endogenous receptor population available to Sendai virus. The total ganglioside fraction of lung was resolved into individual species by HPTLC. Gangliosides of the gangliotetraose series were identified by the specific binding of /sup 125/I-labeled tetanus and cholera toxins before and after exposure with sialidase. In this manner one of the major resorcinol-positive bands was identified as GDla. Evidence of the more complex ganglioside receptors for Sendai virus was also seen.

  2. Apprehending ganglioside diversity: a comprehensive methodological approach[S

    PubMed Central

    Masson, Elodie A. Y.; Sibille, Estelle; Martine, Lucy; Chaux-Picquet, Fanny; Bretillon, Lionel; Berdeaux, Olivier

    2015-01-01

    Gangliosides (GGs) make a wide family of glycosphingolipids ubiquitously expressed in mammalian tissues and particularly abundant in the brain and nervous system. They exhibit a huge diversity due to structural variations in both their oligosaccharidic chain and ceramide moiety, which represent a real analytical challenge. Since their discovery in the 1940s, methods have persistently improved until the emergence of LC/MS, which offers a high level of specificity and sensitivity and is suitable with high-throughput profiling studies. We describe here a comprehensive approach relying on various techniques and aiming at fully characterizing GGs in biological samples. First, total GG content was determined by a biochemical assay. Second, GG class composition was assessed by high-performance thin-layer chromatography followed by colorimetric revelation. Then, ceramide types of GG classes were identified, and their relative quantification was performed thanks to the development of a powerful and reliable LC/MS method. Finally, ceramides were structurally characterized, and minor and less common GG classes were identified using high-resolution MS. These methods were applied to the rat retina to provide an exhaustive description of its GG composition, giving the base for a better understanding of the precise roles of GGs in this tissue. PMID:26142958

  3. Influence of tunicamycin, sialidase, and cholera toxin on gangliosides and T-lymphocyte responses to interleukin 2

    SciTech Connect

    Semmes, O.J.; Bailey, J.M.; Merritt, W.D.

    1986-05-01

    The authors have shown that gangliosides inhibit interleukin 2 (IL 2)-dependent proliferation of murine T cells. Tunicamycin (TM), sialidase, and cholera toxin-..beta.. subunit (..beta..-CT) are known modulators of cell surface glycoconjugates. To test the possible role of endogenous gangliosides in T cell responses to IL-2, the effect of these agents on ganglioside expression and cell proliferation was studied. Gangliosides were labelled for 24 hrs with /sup 3/H-glucosamine/galactose in the presence of IL-2 and purified sialidase, TM or ..beta..-CT. Gangliosides were isolated and the species separated by TLC. Alternatively, proliferation was assayed by /sup 3/H-thymidine uptake after 48 hrs culture. TM treatment at a concentration (10 ..mu..g/ml) that completely inhibited proliferation resulted in a 86% reduction of incorporation of saccharide precursors into gangliosides compared to a 50% reduction into proteins. Sialidase treatment (0.1 IU/ml) resulted in a 70% inhibition of proliferation and 30% reduction of radiolabel into gangliosides, of which 3 species were specifically reduced. ..beta..-CT, which binds to GM/sub 1/ and to a lesser extent GD/sub 1a/, caused a 50% reduction in proliferation response at 35 units/ml. The results support the hypothesis that gangliosides are involved in IL-2-dependent proliferation.

  4. Rare-Earth Ion-Host Lattice Interactions: 15. Analysis of the Spectra of Nd3+ in Gd3Sc2Ga3O12.

    DTIC Science & Technology

    1984-05-01

    of square angstroms. TABLE A -3. EXCERPTS FROM COMPUTER OUTPUT FOR Pr 3 +:Gd 3Sc2 a301 LINE-TO-LINE wr ELECTRIC-DIPOLE TRANSITION PROBABILITY TABLE...MAY 84HDL-R-2035 ARNCLASSIFIED FG74 NEEMEEEEEEE 7.8 I.1I2 MICROCOPY Rc SOIUTION TEST CHART NATIONAL BIA F I A NP [ARIP I F IA Lfl ID N Ic THSRPR...REPORT NUMBER 7. AUTHOR( ) S. CONTRACT OR GRANT NUMBER(e) Clyde A . Morrison Richard P. Leavitt Michael D. Gildner 9. PERFORMING ORGANIZATION NAME AND

  5. Study the effect of Gd3+ incorporation into nanocrystalline (Ni-Ti) substituted Mn-Zn ferrites on its structure and functional properties

    NASA Astrophysics Data System (ADS)

    Rady, K. E.; Shams, M. S.

    2017-03-01

    Ferrite samples with general chemical formula Mn0.9Zn0.1Ni0.05Ti0.05GdtFe1.9-tO4; (0.0≤ t≤0.05; step 0.01) were prepared using solid state reaction technique and the effect of Gd3+ ions incorporation on its physical properties has been studied. From the obtained results, XRD analysis reveals that the samples have a cubic spinel single phase structure for 0.0≤ t≤0.02; while for t≥0.03 a small peak of secondary phase (Gd3Fe5O12) appears and becomes more noticeable with increasing Gd content. The lattice parameter (a) of the prepared samples was found to be initially increases and then decreases with increasing Gd content which may be attributed to the difference in the ionic radii of the cations involved and the solubility limit of Gd3+ ions. The crystallite size of the samples was estimated using Scherrer's equation and ranged from 96 nm to 107 nm. A vibrating sample magnetometer (VSM) was used at room temperature in order to study the effect of Gd content on the magnetic hysteresis parameters of the prepared ferrites such as saturation magnetization and coercivity. DC molar magnetic susceptibility (χM) for the prepared samples was measured using Faraday's method as a function of temperature and the Curie temperature was calculated from the magnetic susceptibility measurements. Also the DC resistivity of the samples was measured at room temperature. The obtained results show that, the substitution by Gd3+ ions improves the electrical properties of the samples by increasing it DC electrical resistivity by 118% and consequently decreases it eddy current loss while the saturation magnetization slightly decreased by 14% only. The sample of t=0.01 shows a high dc magnetic susceptibility, high saturation magnetization (43.1 emu/g), high electric resistivity 12×103 Ω.m and high Curie temperature (496 K), which is useful in some technological applications such as transformer and inductor cores.

  6. Selection of ganglioside GM1-binding peptides by using a phage library.

    PubMed

    Matsubara, T; Ishikawa, D; Taki, T; Okahata, Y; Sato, T

    1999-08-06

    Ganglioside Gal beta1 --> 3GalNAc beta1 --> 4(NeuAc alpha2 --> 3) Gal beta1 --> 4Glc beta1 -->1'Cer (GM1)-binding peptides were obtained from a phage-displayed pentadecapeptide library by an affinity selection. The selection processes were in situ-monitored by a quartz-crystal microbalance method, on which a ganglioside GM1 monolayer was transferred. After five rounds of biopanning, the DNA sequencing of 18 selected phages showed that only three individual clones were selected. The peptide sequences of the random region were found to be DFRRLPGAFWQLRQP, GWWYKGRARPVSAVA and VWRLLAPPFSNRLLP. Binding constants of these phage clones to the GM1 monolayer were 10(10) M(-1). Three synthetic pentadecapeptides inhibited the binding of cholera toxin B subunit to the GM1 monolayer with an IC50 of 24, 13 and 1.0 microM, respectively. These peptides will be useful for searching functional roles of ganglioside GMI.

  7. NGcGM3 Ganglioside: A Privileged Target for Cancer Vaccines

    PubMed Central

    Fernandez, Luis E.; Gabri, Mariano R.; Guthmann, Marcelo D.; Gomez, Roberto E.; Gold, Silvia; Fainboim, Leonardo; Gomez, Daniel E.; Alonso, Daniel F.

    2010-01-01

    Active specific immunotherapy is a promising field in cancer research. N-glycolyl (NGc) gangliosides, and particularly NGcGM3, have received attention as a privileged target for cancer therapy. Many clinical trials have been performed with the anti-NGc-containing gangliosides anti-idiotype monoclonal antibody racotumomab (formerly known as 1E10) and the conjugated NGcGM3/VSSP vaccine for immunotherapy of melanoma, breast, and lung cancer. The present paper examines the role of NGc-gangliosides in tumor biology as well as the available preclinical and clinical data on these vaccine products. A brief discussion on the relevance of prioritization of cancer antigens in vaccine development is also included. PMID:21048926

  8. Differential subcellular localization of cholesterol, gangliosides, and glycosaminoglycans in murine models of mucopolysaccharide storage disorders.

    PubMed

    McGlynn, Robert; Dobrenis, Kostantin; Walkley, Steven U

    2004-12-20

    The mucopolysaccharidoses (MPSs) are a complex family of lysosomal storage disorders characterized by failure to degrade heparan sulfate (HS) and/or other types of glycosaminoglycans (GAGs) secondary to the absence of specific lysosomal enzymes. An accompanying storage of glycosphingolipids (GSLs), most notably GM2 and GM3 gangliosides, has also been documented to occur in many types of MPS disease and is believed to be caused by secondary inhibition of GSL-degradative enzymes by intracellular GAG accumulation. We have documented the presence of secondary ganglioside accumulation in mouse models of several MPS disorders (types I, IIIA, IIIB, and VII) and report that this storage is accompanied by sequestration of free cholesterol in a manner similar to that observed in primary gangliosidoses. Using confocal microscopy, we evaluated the cellular distribution of cholesterol, GM2 and GM3 gangliosides, and HS in brains of mice with MPS IIIA disease. Unexpectedly, we found that although both gangliosides often accumulated in the same neurons, they were consistently located in separate populations of cytoplasmic vesicles. Additionally, GM3 ganglioside only partially co-localized with the primary storage material (HS), and cholesterol likewise only partially co-localized with the GM2 and GM3 gangliosides. These findings raise significant questions about the mechanism(s) responsible for secondary accumulation of storage materials in MPS disease. Furthermore, given that GSLs and cholesterol are constituents of membrane rafts believed critical in signal transduction events in neurons, their co-sequestration in individual neurons suggests the presence of defects in the composition, trafficking, and/or recycling of raft components and thus possible new mechanisms to explain neuronal dysfunction in MPS disorders.

  9. Biosynthesis of the major brain gangliosides GD1a and GT1b.

    PubMed

    Sturgill, Elizabeth R; Aoki, Kazuhiro; Lopez, Pablo H H; Colacurcio, Daniel; Vajn, Katarina; Lorenzini, Ileana; Majić, Senka; Yang, Won Ho; Heffer, Marija; Tiemeyer, Michael; Marth, Jamey D; Schnaar, Ronald L

    2012-10-01

    Gangliosides-sialylated glycosphingolipids-are the major glycoconjugates of nerve cells. The same four structures-GM1, GD1a, GD1b and GT1b-comprise the great majority of gangliosides in mammalian brains. They share a common tetrasaccharide core (Galβ1-3GalNAcβ1-4Galβ1-4Glcβ1-1'Cer) with one or two sialic acids on the internal galactose and zero (GM1 and GD1b) or one (GD1a and GT1b) α2-3-linked sialic acid on the terminal galactose. Whereas the genes responsible for the sialylation of the internal galactose are known, those responsible for terminal sialylation have not been established in vivo. We report that St3gal2 and St3gal3 are responsible for nearly all the terminal sialylation of brain gangliosides in the mouse. When brain ganglioside expression was analyzed in adult St3gal1-, St3gal2-, St3gal3- and St3gal4-null mice, only St3gal2-null mice differed significantly from wild type, expressing half the normal amount of GD1a and GT1b. St3gal1/2-double-null mice were no different than St3gal2-single-null mice; however, St3gal2/3-double-null mice were >95% depleted in gangliosides GD1a and GT1b. Total ganglioside expression (lipid-bound sialic acid) in the brains of St3gal2/3-double-null mice was equivalent to that in wild-type mice, whereas total protein sialylation was reduced by half. St3gal2/3-double-null mice were small, weak and short lived. They were half the weight of wild-type mice at weaning and displayed early hindlimb dysreflexia. We conclude that the St3gal2 and St3gal3 gene products (ST3Gal-II and ST3Gal-III sialyltransferases) are largely responsible for ganglioside terminal α2-3 sialylation in the brain, synthesizing the major brain gangliosides GD1a and GT1b.

  10. Role of Ce4+ in the Scintillation Mechanism of Codoped Gd3Ga3Al2O12∶Ce

    NASA Astrophysics Data System (ADS)

    Wu, Yuntao; Meng, Fang; Li, Qi; Koschan, Merry; Melcher, Charles L.

    2014-10-01

    To control the time-response performance of widely used cerium-activated scintillators in cutting-edge medical-imaging devices, such as time-of-flight positron-emission tomography, a comprehensive understanding of the role of Ce valence states, especially stable Ce44, in the scintillation mechanism is essential. However, despite some progress made recently, an understanding of the physical processes involving Ce4+ is still lacking. The aim of this work is to clarify the role of Ce4+ in scintillators by studying Ca2+ codoped Gd3Ga3Al2O12∶Ce (GGAG ∶Ce). By using a combination of optical absorption spectra and x-ray absorption near-edge spectroscopies, the correlation between Ca2+ codoping content and the Ce4+ fraction is seen. The energy-level diagrams of Ce3+ and Ce4+ in the Gd3Ga3Al2O12 host are established by using theoretical and experimental methods, which indicate a higher position of the 5d1 state of Ce4+ in the forbidden gap in comparison to that of Ce3+. Underlying reasons for the decay-time acceleration resulting from Ca2+ codoping are revealed, and the physical processes of the Ce4+-emission model are proposed and further demonstrated by temperature-dependent radioluminescence spectra under x-ray excitation.

  11. Investigation of cyano-bridged coordination nanoparticles Gd3+/[Fe(CN)6]3-/d-mannitol as T1-weighted MRI contrast agents

    NASA Astrophysics Data System (ADS)

    Perrier, M.; Gallud, A.; Ayadi, A.; Kennouche, S.; Porredon, C.; Gary-Bobo, M.; Larionova, J.; Goze-Bac, Ch.; Zanca, M.; Garcia, M.; Basile, I.; Long, J.; de Lapuente, J.; Borras, M.; Guari, Y.

    2015-07-01

    Cyano-bridged Gd3+/[Fe(CN)6]3- coordination polymer nanoparticles of 3-4 nm stabilized with d-mannitol presenting a high r1 relaxivity value of 11.4 mM-1 s-1 were investigated in vivo as contrast agents (CA) for Magnetic Resonance Imaging (MRI). They allow an increase of the MR image contrast and can act as an efficient intravascular T1 CA with a relatively long blood-circulation lifetime (60 min) without specific toxicity.Cyano-bridged Gd3+/[Fe(CN)6]3- coordination polymer nanoparticles of 3-4 nm stabilized with d-mannitol presenting a high r1 relaxivity value of 11.4 mM-1 s-1 were investigated in vivo as contrast agents (CA) for Magnetic Resonance Imaging (MRI). They allow an increase of the MR image contrast and can act as an efficient intravascular T1 CA with a relatively long blood-circulation lifetime (60 min) without specific toxicity. Electronic supplementary information (ESI) available: Experimental details and procedures, toxicological data, physical characterization. See DOI: 10.1039/c5nr01557j

  12. Effect of Mg2+ ions co-doping on luminescence and defects formation processes in Gd3(Ga,Al)5O12:Ce single crystals

    NASA Astrophysics Data System (ADS)

    Babin, V.; Bohacek, P.; Grigorjeva, L.; Kučera, M.; Nikl, M.; Zazubovich, S.; Zolotarjovs, A.

    2017-04-01

    Photo- and radioluminescence and thermally stimulated luminescence characteristics of Ce3+ - doped and Ce3+, Mg2+ co-doped Gd3(Ga,Al)5O12 (GAGG) single crystals of similar composition are investigated in the 9-500 K temperature range. The Ce3+ - related luminescence spectra and the photoluminescence decay kinetics in these crystals are found to be similar. Under photoexcitation in the Ce3+ - and Gd3+ - related absorption bands, no prominent rise of the photoluminescence intensity in time is observed neither in GAGG:Ce,Mg nor in GAGG:Ce crystals. The afterglow is strongly reduced in GAGG:Ce,Mg as compared to GAGG:Ce, and the afterglow decay kinetics is much faster. Co-doping with Mg2+ results in a drastic decrease of the thermally stimulated luminescence (TSL) intensity in the whole investigated temperature range and in the appearance of a new complex Mg2+ - related TSL glow curve peak around 285 K. After irradiation in the Ce3+ - related 3.6 eV absorption band, the TSL intensity in GAGG:Ce,Mg is found to be comparable with that in the GAGG:Ce epitaxial film of similar composition. The Mg2+ - induced changes in the concentration, origin and structure of the crystal lattice defects and their influence on the scintillation characteristics of GAGG:Ce,Mg are discussed.

  13. Charge deformation and orbital hybridization: intrinsic mechanisms on tunable chromaticity of Y3Al5O12:Ce3+ luminescence by doping Gd3+ for warm white LEDs

    PubMed Central

    Chen, Lei; Chen, Xiuling; Liu, Fayong; Chen, Haohong; Wang, Hui; Zhao, Erlong; Jiang, Yang; Chan, Ting-Shan; Wang, Chia-Hsin; Zhang, Wenhua; Wang, Yu; Chen, Shifu

    2015-01-01

    The deficiency of Y3Al5O12:Ce (YAG:Ce) luminescence in red component can be compensated by doping Gd3+, thus lead to it being widely used for packaging warm white light-emitting diode devices. This article presents a systematic study on the photoluminescence properties, crystal structures and electronic band structures of (Y1−xGdx)3Al5O12: Ce3+ using powerful experimental techniques of thermally stimulated luminescence, X-ray diffraction, X-ray absorption near edge structure (XANES), extended X-ray absorption fine structure (EXAFS) and ultraviolet photoelectron spectra (UPS) of the valence band, assisted with theoretical calculations on the band structure, density of states (DOS), and charge deformation density (CDD). A new interpretation from the viewpoint of compression deformation of electron cloud in a rigid structure by combining orbital hybridization with solid-state energy band theory together is put forward to illustrate the intrinsic mechanisms that cause the emission spectral shift, thermal quenching, and luminescence intensity decrease of YAG: Ce upon substitution of Y3+ by Gd3+, which are out of the explanation of the classic configuration coordinate model. The results indicate that in a rigid structure, the charge deformation provides an efficient way to tune chromaticity, but the band gaps and crystal defects must be controlled by comprehensively accounting for luminescence thermal stability and efficiency. PMID:26175141

  14. Effect of Gd3+ substitution on the structural and electrical properties of Mg0.75Zn0.25Fe2O4 nanoparticles

    NASA Astrophysics Data System (ADS)

    Sebastian, R. M.; Mohammed, E. M.

    2016-12-01

    Nanoparticles of gadolinium substituted Mg-Zn ferrite, Mg0.75Zn0.25GdxFe2-xO4 (where x = 0.00, 0.05, 0.10, 0.15) have been prepared by the sol-gel technique. The lattice constant is found to increase with increase in the Gd3+ ion concentration. The observed variation of dielectric constant with frequency is explained on the basis of the Maxwell-Wagner two layer model and the electron hopping mechanism. The dielectric constant and dielectric loss decrease with Gd3+ ion substitution. The variation of AC conductivity with frequency suggests that the conduction is due to small polaron hopping. It is also noticed that the dielectric constant and the AC conductivity increase with temperature and it is explained in terms of the thermally enhanced drift mobility of the charge carriers. The observed low value of dielectric constant and also the dielectric loss factor obtained for gadolinium substituted ferrites make them desirable for high frequency applications.

  15. 5 7 Fe Emission Mössbauer Study on Gd 3 Ga 5 O 1 2 implanted with dilute 5 7 Mn

    NASA Astrophysics Data System (ADS)

    Krastev, P. B.; Gunnlaugsson, H. P.; Nomura, K.; Adoons, V.; Gerami, A. M.; Johnston, K.; Ncube, M.; Mantovan, R.; Masenda, H.; Matveyev, Y. A.; Mølholt, T. E.; Unzueta, I.; Bharuth-Ram, K.; Gislason, H.; Langouche, G.; Naidoo, D.; Ólafsson, S.

    2016-12-01

    57Fe emission Mössbauer spectroscopy has been applied to study the lattice location and properties of Fe in gadolinium gallium garnet Gd3Ga5 O 12 (GGG) single crystals in the temperature interval 300 - 563 K within the extremely dilute (<10-4 at.%) regime following the implantation of57Mn ( T 1 / 2= 1.5 min.) at ISOLDE/CERN. These results are compared with earlier Mössbauer spectroscopy study of Fe-doped gadolinium gallium garnet Gd3Ga5 O 12(GGG), with implantation fluences between 8×1015 and 6×1016 atoms cm-2. Three Fe components are observed in the emission Mössbauer spectra: (i) high spin Fe2+ located at damage sites due to the implantation process, (ii) high spin Fe3+ at substitutional tetrahedral Ga sites, and (iii) interstitial Fe, probably due to the recoil imparted on the daughter57∗Fe nucleus in the β - decay of57Mn. In contrast to high fluence57Fe implantation studies the Fe3+ ions are found to prefer the tetrahedral Ga site over the octahedral Ga site. No annealing stages are evident in the temperature range investigated. Despite the very low concentration, high-spin Fe3+ shows fast spin relaxation, presumably due to an indirect interaction between nearby gadolinium atoms.

  16. Ultraviolet-light-emitting AlN:Gd thin-film electroluminescence device using an energy transfer from Gd3+ ions to N2 molecules

    NASA Astrophysics Data System (ADS)

    Toyama, Toshihiko; Ota, Jun; Adachi, Daisuke; Niioka, Yasumasa; Lee, Dong-Hun; Okamoto, Hiroaki

    2009-04-01

    An ultraviolet (UV)-light-emitting AlN:Gd thin-film electroluminescence device (TFELD) was demonstrated for application to flat-panel lighting. AlN:Gd thin films were deposited by rf magnetron sputtering at 200 °C and applied to an ac-voltage-driven TFELD with a double-insulating structure as an emission layer. UV-light emission was observed over a threshold voltage of 270 V for a 5 kHz sinusoidal ac voltage. Electroluminescence (EL) spectra were compared with photoluminescence and cathodoluminescence spectra of AlN:Gd originating from Gd3+ P6j→S87/2 transitions and with an emission spectrum of the second positive system (C3Πu→B3Πg) of N2 molecules. As a result, an energy transfer from Gd3+ P6j→S87/2 to N2 C3Πu→B3Πg is discussed as a likely mechanism for the UV EL. Finally, a preliminary result, associated with the conversion from UV light into blue-green light via a phosphor, is demonstrated for the color tunability of the TFELD.

  17. Charge deformation and orbital hybridization: intrinsic mechanisms on tunable chromaticity of Y3Al5O12:Ce3+ luminescence by doping Gd3+ for warm white LEDs.

    PubMed

    Chen, Lei; Chen, Xiuling; Liu, Fayong; Chen, Haohong; Wang, Hui; Zhao, Erlong; Jiang, Yang; Chan, Ting-Shan; Wang, Chia-Hsin; Zhang, Wenhua; Wang, Yu; Chen, Shifu

    2015-07-15

    The deficiency of Y3Al5O12:Ce (YAG:Ce) luminescence in red component can be compensated by doping Gd(3+), thus lead to it being widely used for packaging warm white light-emitting diode devices. This article presents a systematic study on the photoluminescence properties, crystal structures and electronic band structures of (Y1-xGdx)3Al5O12: Ce(3+) using powerful experimental techniques of thermally stimulated luminescence, X-ray diffraction, X-ray absorption near edge structure (XANES), extended X-ray absorption fine structure (EXAFS) and ultraviolet photoelectron spectra (UPS) of the valence band, assisted with theoretical calculations on the band structure, density of states (DOS), and charge deformation density (CDD). A new interpretation from the viewpoint of compression deformation of electron cloud in a rigid structure by combining orbital hybridization with solid-state energy band theory together is put forward to illustrate the intrinsic mechanisms that cause the emission spectral shift, thermal quenching, and luminescence intensity decrease of YAG: Ce upon substitution of Y(3+) by Gd(3+), which are out of the explanation of the classic configuration coordinate model. The results indicate that in a rigid structure, the charge deformation provides an efficient way to tune chromaticity, but the band gaps and crystal defects must be controlled by comprehensively accounting for luminescence thermal stability and efficiency.

  18. Explanation for the variance of the Ce 3+ emission energy in LnI 3 [Ln = Lu 3+, Y 3+, Gd 3+

    NASA Astrophysics Data System (ADS)

    Srivastava, A. M.; Camardello, S. J.; Comanzo, H. A.; Aycibin, M.; Happek, U.

    2010-07-01

    The experimental result that the energy of the emitted photon increases with decreasing ionic radii of the host lattice is a remarkable feature of the Ce 3+ luminescence in the isostructural LnI 3 [Ln 3+ = Lu 3+, Y 3+, Gd 3+] family of materials. To understand this variation, the optical properties of YI 3:Ce 3+ is measured and compared with those reported for Ce 3+ activated LuI 3 and GdI 3. The results indicate that the crystal field splitting and the centroid shift of the Ce 3+ 5d 1 electronic configuration in these iodides are of the same order of magnitude. The lowest energy Ce 3+ 4f 1 → 5d 1 excitation transition in LnI 3 [Ln 3+ = Lu 3+, Y 3+, Gd 3+] is practically uninfluenced by the ionic radii of the host lattice cation, which the Ce 3+ ion substitutionally replaces. The increase in energy of the emitted photon with decreasing ionic radii of the host lattice is a result of the increasing Stokes shift of the Ce 3+ emission in the sequence LuI 3-YI 3-GdI 3. The quenching temperature of the Ce 3+ emission in YI 3 is high.

  19. (1)H relaxivity of water in aqueous suspensions of Gd(3+)-loaded NaY nanozeolites and AlTUD-1 mesoporous material: the influence of Si/Al ratio and pore size.

    PubMed

    Norek, Małgorzata; Neves, Isabel C; Peters, Joop A

    2007-07-23

    The results of a (1)H nuclear magnetic relaxation dispersion (NMRD) and EPR study on aqueous suspensions of Gd(3+)-loaded NaY nanozeolites and AlTUD-1 mesoporous material are described. Upon increase of the Si/Al ratio from 1.7 to 4.0 in the Gd(3+)-loaded zeolites, the relaxation rate per mM Gd(3+) (r1) at 40 MHz and 25 degrees C increases from 14 to 27 s(-)1 mM(-1). The NMRD and EPR data were fitted with a previously developed two-step model that considers the system as a concentrated aqueous solution of Gd(3+) in the interior of the zeolite that is in exchange with the bulk water outside the zeolite. The results show that the observed increase in relaxivity can mainly be attributed to the residence lifetime of the water protons in the interior of the material, which decreased from 0.3 to 0.2 micros, upon the increase of the Si/Al ratio. This can be explained by the decreased interaction of water with the zeolite walls as a result of the increased hydrophobicity. The importance of the exchange rate of water between the inside and the outside of the material was further demonstrated by the relatively high relaxivity (33 s(-1) mM(-1) at 40 MHz, 25 degrees C) observed for a suspension of the Gd(3+)-loaded mesoporous material AlTUD-1. Unfortunately, Gd(3+) leaches rather easily from that material, but not from the Gd(3+)-loaded NaY zeolites, which may have potential as contrast agents for magnetic resonance imaging.

  20. Characterization of the cholera toxin receptor on Balb/c 3T3 cells as a ganglioside similar to, or identical with, ganglioside GM1. No evidence for galactoproteins with receptor activity.

    PubMed

    Critchley, D R; Streuli, C H; Kellie, S; Ansell, S; Patel, B

    1982-04-15

    Balb/c 3T3 cells contain a large number [(0.8-1.6) x 10(6)] of high-affinity (half-maximal binding at 0.2 nM) binding sites for cholera toxin that are resistant to proteolysis, but are quantitatively extracted with chloroform/methanol. The following evidence rigorously establishes that the receptor is a ganglioside similar to, or identical with, ganglioside GM1 by the galactose oxidase/NaB3H4 technique on intact cells was inhibited by cholera toxin. (2) Ganglioside GM1 was specifically adsorbed from Nonidet P40 extracts of both surface- (galactose oxidase/NaB3H4 technique) and metabolically ([1-14C]palmitate) labelled cells in the presence of cholera toxin, anti-toxin and Staphylococcus aureus. (3) Ganglioside GM1 was the only ganglioside labelled when total cellular gangliosides separated on silica-gel sheets were overlayed with 125I-labelled cholera toxin, although GM3 and GD1a were the major gangliosides present. In contrast no evidence for a galactoprotein with receptor activity was obtained. Cholera toxin did not protect the terminal galactose residues of cell-surface glycoproteins from labelling by the galactose oxidase/NaB3H4 technique. No toxin-binding proteins could be identified in Nonidet P40 extracts of [35S]-methionine-labelled cells by immunochemical means. After sodium dodecyl sulphate/polyacrylamide-gel electrophoresis none of the major cellular galactoproteins identified by overlaying gels with 125I-labelled ricin were able to bind 125I-labelled cholera toxin. It is concluded that the cholera toxin receptor on Balb/c 3T3 cells is exclusively ganglioside GM1 (or a related species), and that cholera toxin can therefore be used to probe the function and organisation of gangliosides in these cells as previously outlined [Critchley, Ansell, Perkins, Dilks & Ingram (1979) J. Supramol. Struct. 12, 273-291].

  1. Phosphatidylinositol 4-phosphate 5-kinase α is induced in ganglioside-stimulated brain astrocytes and contributes to inflammatory responses

    PubMed Central

    Kim, Bokyung; Yoon, Sarah; Kim, Yeon Joo; Liu, Tian; Woo, Joo Hong; Chwae, Yong-Joon; Joe, Eun-hye; Jou, Ilo

    2010-01-01

    In brain tissue, astrocytes play defensive roles in central nervous system integrity by mediating immune responses against pathological conditions. Type I phosphatidylinositol 4-phosphate 5-kinase α (PIP5Kα) that is responsible for production of phosphatidylinositol 4,5-bisphosphate (PI[4,5]P2) regulates many important cell functions at the cell surface. Here, we have examined whether PIP5Kα is associated with astrocyte inflammatory responses. Gangliosides are releasable from damaged cell membranes of neurons and capable of inducing inflammatory responses. We found that treatment of primary cultured astrocytes with gangliosides significantly enhanced PIP5Kα mRNA and protein expression levels. PI(4,5)P2 imaging using a fluorescent tubby (R332H) expression as a PI(4,5)P2-specific probe showed that ganglioside treatment increased PI(4,5)P2 level. Interestingly, microRNA-based PIP5Kα knockdown strongly reduced ganglioside-induced transcription of proinflammatory cytokines IL-1β and TNFα. PIP5Kα knockdown also suppressed ganglioside-induced phosphorylation and nuclear translocation of NF-κB and the degradation of IκB-α, indicating that PIP5Kα knockdown interfered with the ganglioside-activated NF-κB signaling. Together, these results suggest that PIP5Kα is a novel inflammatory mediator that undergoes upregulation and contributes to immune responses by facilitating NF-κB activation in ganglioside-stimulated astrocytes. PMID:20720456

  2. Broad neutralization of calcium-permeable amyloid pore channels with a chimeric Alzheimer/Parkinson peptide targeting brain gangliosides.

    PubMed

    Di Scala, Coralie; Yahi, Nouara; Flores, Alessandra; Boutemeur, Sonia; Kourdougli, Nazim; Chahinian, Henri; Fantini, Jacques

    2016-02-01

    Growing evidence supports a role for brain gangliosides in the pathogenesis of neurodegenerative diseases including Alzheimer's and Parkinson's. Recently we deciphered the ganglioside-recognition code controlling specific ganglioside binding to Alzheimer's β-amyloid (Aβ1-42) peptide and Parkinson's disease-associated protein α-synuclein. Cracking this code allowed us to engineer a short chimeric Aβ/α-synuclein peptide that recognizes all brain gangliosides. Here we show that ganglioside-deprived neural cells do no longer sustain the formation of zinc-sensitive amyloid pore channels induced by either Aβ1-42 or α-synuclein, as assessed by single-cell Ca(2+) fluorescence microscopy. Thus, amyloid channel formation, now considered a key step in neurodegeneration, is a ganglioside-dependent process. Nanomolar concentrations of chimeric peptide competitively inhibited amyloid pore formation induced by Aβ1-42 or α-synuclein in cultured neural cells. Moreover, this peptide abrogated the intracellular calcium increases induced by Parkinson's-associated mutant forms of α-synuclein (A30P, E46K and A53T). The chimeric peptide also prevented the deleterious effects of Aβ1-42 on synaptic vesicle trafficking and decreased the Aβ1-42-induced impairment of spontaneous activity in rat hippocampal slices. Taken together, these data show that the chimeric peptide has broad anti-amyloid pore activity, suggesting that a common therapeutic strategy based on the prevention of amyloid-ganglioside interactions is a reachable goal for both Alzheimer's and Parkinson's diseases.

  3. Dissecting the Role of Anti-ganglioside Antibodies in Guillain-Barré Syndrome: an Animal Model Approach.

    PubMed

    Asthana, Pallavi; Vong, Joaquim Si Long; Kumar, Gajendra; Chang, Raymond Chuen-Chung; Zhang, Gang; Sheikh, Kazim A; Ma, Chi Him Eddie

    2016-09-01

    Guillain-Barré syndrome (GBS) is an autoimmune polyneuropathy disease affecting the peripheral nervous system (PNS). Most of the GBS patients experienced neurological symptoms such as paresthesia, weakness, pain, and areflexia. There are also combinations of non-neurological symptoms which include upper respiratory tract infection and diarrhea. One of the major causes of GBS is due largely to the autoantibodies against gangliosides located on the peripheral nerves. Gangliosides are sialic acid-bearing glycosphingolipids consisting of a ceramide lipid anchor with one or more sialic acids attached to a neutral sugar backbone. Molecular mimicry between the outer components of oligosaccharide of gangliosides on nerve membrane and lipo-oligosaccharide of microbes is thought to trigger the autoimmunity. Intra-peritoneal implantation of monoclonal ganglioside antibodies secreting hybridoma into animals induced peripheral neuropathy. Recent studies demonstrated that injection of synthesized anti-ganglioside antibodies raised by hybridoma cells into mice initiates immune response against peripheral nerves, and eventually failure in peripheral nerve regeneration. Accumulating evidences indicate that the conjugation of anti-ganglioside monoclonal antibodies to activating FcγRIII present on the circulating macrophages inhibits axonal regeneration. The activation of RhoA signaling pathways is also involved in neurite outgrowth inhibition. However, the link between these two molecular events remains unresolved and requires further investigation. Development of anti-ganglioside antagonists can serve as targeted therapy for the treatment of GBS and will open a new approach of drug development with maximum efficacy and specificity.

  4. Involvement of gangliosides in the suppression of the immune response: an explanation for the progression of UV-induced fibrosarcomas

    SciTech Connect

    Frey, J.L.

    1987-01-01

    Ultraviolet-irradiation-induced fibrosarcoma cells with either progressor or regressor properties were studied for structural differences in their glycosphingolipid (GSL) content and composition. UV-progressor tumor cells contained a ganglioside, G/sub Dla/, which the UV-regressor cells lacked. This ganglioside was found in the serum of tumor bearing animals and was shed from the UV-progressor tumor cells. In our analysis of the role gangliosides might play in the tumor progression, we found that both spent medium and crude ganglioside preparations from progressor UV-tumor cells inhibited the mitogenic proliferation of normal lymphocytes. In vitro analysis with purified preparations of G/sub Dla/ showed that this ganglioside had immunosuppressive properties in mitogen-stimulated cultures. The kinetics of the inhibition response showed that maximal inhibition occurred if G/sub Dla/ was present at the prereplicative stage of lymphocyte proliferation. If lymphocytes are precultured with G/sub Dla/, exogenous ganglioside could be removed without loss of the inhibitory activity on lymphocyte proliferation. These results suggest that the presence of the ganglioside, G/sub Dla/, on the cell surface of progressor tumors could alter an immune response

  5. Structural Basis of GD2 Ganglioside and Mimetic Peptide Recognition by 14G2a Antibody*

    PubMed Central

    Horwacik, Irena; Golik, Przemyslaw; Grudnik, Przemyslaw; Kolinski, Michal; Zdzalik, Michal; Rokita, Hanna; Dubin, Grzegorz

    2015-01-01

    Monoclonal antibodies targeting GD2 ganglioside (GD2) have recently been approved for the treatment of high risk neuroblastoma and are extensively evaluated in clinics in other indications. This study illustrates how a therapeutic antibody distinguishes between different types of gangliosides present on normal and cancer cells and informs how synthetic peptides can imitate ganglioside in its binding to the antibody. Using high resolution crystal structures we demonstrate that the ganglioside recognition by a model antibody (14G2a) is based primarily on an extended network of direct and water molecule mediated hydrogen bonds. Comparison of the GD2-Fab structure with that of a ligand free antibody reveals an induced fit mechanism of ligand binding. These conclusions are validated by directed mutagenesis and allowed structure guided generation of antibody variant with improved affinity toward GD2. Contrary to the carbohydrate, both evaluated mimetic peptides utilize a “key and lock” interaction mechanism complementing the surface of the antibody binding groove exactly as found in the empty structure. The interaction of both peptides with the Fab relies considerably on hydrophobic contacts however, the detailed connections differ significantly between the peptides. As such, the evaluated peptide carbohydrate mimicry is defined primarily in a functional and not in structural manner. PMID:26179345

  6. Ganglioside GT1b protects human spermatozoa from hydrogen peroxide-induced DNA and membrane damage.

    PubMed

    Gavella, Mirjana; Garaj-Vrhovac, Verica; Lipovac, Vaskresenija; Antica, Mariastefania; Gajski, Goran; Car, Nikica

    2010-06-01

    We have reported previously that various gangliosides, the sialic acid containing glycosphingolipids, provide protection against sperm injury caused by reactive oxygen species (ROS). In this study, we investigated the effect of treatment of human spermatozoa with ganglioside GT1b on hydrogen peroxide (H(2)O(2))-induced DNA fragmentation and plasma membrane damage. Single-cell gel electrophoresis (Comet assay) used in the assessment of sperm DNA integrity showed that in vitro supplemented GT1b (100 microm) significantly reduced DNA damage induced by H(2)O(2) (200 microm) (p < 0.05). Measurements of Annexin V binding in combination with the propidium iodide vital dye labelling demonstrated that the spermatozoa pre-treated with GT1b exhibited a significant increase (p < 0.05) in the percentage of live cells with intact membrane and decreased phosphatidylserine translocation after exposure to H(2)O(2). Flow cytometry using the intracellular ROS-sensitive fluorescence dichlorodihydrofluorescein diacetate dye employed to investigate the transport of the extracellularly supplied H(2)O(2) into the cell interior revealed that ganglioside GT1b completely inhibited the passage of H(2)O(2) through the sperm membrane. These results suggest that ganglioside GT1b may protect human spermatozoa from H(2)O(2)-induced damage by rendering sperm membrane more hydrophobic, thus inhibiting the diffusion of H(2)O(2) across the membrane.

  7. Ganglioside mediate the interaction between Nogo receptor 1 and LINGO-1.

    PubMed

    Saha, Nayanendu; Kolev, Momchil V; Semavina, Mariya; Himanen, Juha; Nikolov, Dimitar B

    2011-09-16

    Upon spinal cord injury, the myelin inhibitors, including the myelin-associated glycoprotein (MAG), Nogo-A and the oligodendrocyte myelin glycoprotein (OMgp), bind to and signal via a single neuronal receptor/co-receptor complex comprising of Nogo receptor 1(NgR1)/LINGO-1 and p75 or TROY, impeding regeneration of injured axons. We employed a cell-free system to study the binding of NgR1 to its co-receptors and the myelin inhibitor Nogo-A, and show that gangliosides mediate the interaction of NgR1 with LINGO-1. Solid phase binding assays demonstrate that the sialic acid moieties of gangliosides and the stalk of NgR1 are the principal determinants of these molecular interactions. Moreover, the tripartite complex comprising of NgR1, LINGO-1 and ganglioside exhibits stronger binding to Nogo-A (Nogo-54) in the presence of p75, suggesting the gangliosides modulate the myelin inhibitor-receptor signaling.

  8. GM1 ganglioside is involved in epigenetic activation loci of neuronal cells

    PubMed Central

    Tsai, Yi-Tzang; Itokazu, Yutaka; Yu, Robert K.

    2015-01-01

    Gangliosides are sialic acid-containing glycosphingolipids that are most abundant in the nerve tissues. The quantity and expression pattern of gangliosides in brain change drastically throughout development and are mainly regulated through stage-specific expression of glycosyltransferase (ganglioside synthase) genes. We previously demonstrated that acetylation of histones H3 and H4 on the N-acetylgalactosaminyltransferase I (GalNAcT, GA2/GM2/GD2/GT2-synthase) gene promoter resulted in recruitment of trans-activation factors. In addition, we reported that epigenetic activation of the GalNAcT gene was also detected as accompanied by an apparent induction of neuronal differentiation in neural stem cells responding to an exogenous supplement of ganglioside GM1. Here, we present evidence supporting the concept that nuclear GM1 is associated with gene regulation in neuronal cells. We found that nuclear GM1 binds acetylated histones on the promoters of the GalNAcT and NeuroD1 genes in differentiated neurons. Our study demonstrates for the first time that GM1 interacts with chromatin via acetylated histones at the nuclear periphery of neuronal cells. PMID:26498762

  9. Neuritogenic activity of gangliosides from echinoderms and their structure-activity relationship.

    PubMed

    Kaneko, Masafumi; Yamada, Koji; Miyamoto, Tomofumi; Inagaki, Masanori; Higuchi, Ryuichi

    2007-03-01

    The effects of the gangliosides isolated from echinoderms on the neuritogenesis of a rat pheochromocytoma cell line (PC-12 cells) in the presence of nerve growth factor were investigated. The results show that they displayed neuritogenic activity. Based on the observed results, a structure-activity relationship has been established.

  10. Beyond gangliosides: Multiple forms of glycan mimicry exhibited by Campylobacter jejuni in its lipooligosaccharide (LOS)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Campylobacter jejuni is well known for synthesizing ganglioside mimics within the glycan component of its lipooligosaccharide (LOS), which have been implicated in triggering Guillain-Barré syndrome (GBS). We now confirm that this pathogen is capable of synthesizing a much broader spectrum of host g...

  11. Synthesis and complexation properties of DTPA-N,N''-bis[bis(n-butyl)]-N'-methyl-tris(amide). Kinetic stability and water exchange of its Gd3+ complex.

    PubMed

    Jaszberényi, Z; Tóth, E; Kálai, T; Király, R; Burai, L; Brücher, E; Merbach, A E; Hideg, K

    2005-02-21

    A novel DTPA-tris(amide) derivative ligand, DTPA-N,N''-bis[bis(n-butyl)]-N'-methyl-tris(amide)(H2L3) was synthesized. With Gd3+, it forms a positively charged [Gd(L3)]+ complex, whereas with Cu2+ and Zn2+ [ML3], [MHL3]+ and [M2L3]2+ species are formed. The protonation constants of H2L3 and the stability constants of the complexes were determined by pH potentiometry. The stability constants are lower than those for DTPA-N,N''-bis[bis(n-butyl)amide)](H3L2), due to the lower negative charge and reduced basicity of the amine nitrogens in (L3)2-. The kinetic stability of [Gd(L3)]+ was characterised by the rates of metal exchange reactions with Eu3+, Cu2+ and Zn2+. The exchange reactions, which occur via proton and metal ion assisted dissociation of [Gd(L3)]+, are significantly slower than for [Gd(DTPA)]2-, since the amide groups cannot be protonated and interact only weakly with the attacking metal ions. The relaxivities of [Gd(L2)] and [Gd(L3)]+ are constant between 10-20 degrees C, indicating a relatively slow water exchange. Above 25 degrees C, the relaxivities decrease, similarly to other Gd3+ DTPA-bis(amide) complexes. The pH dependence of the relaxivities for [Gd(L3)]+ shows a minimum at pH approximately 9, thus differs from the behaviour of Gd3+-DTPA-bis(amides) which have constant relaxivities at pH 3-8 and an increase below and above. The water exchange rates for [Gd(L2)(H2O)] and [Gd(L3)(H2O)]+, determined from a variable temperature (17)O NMR study, are lower than that for [Gd(DTPA)(H2O)]2-. This is a consequence of the lower negative charge and decreased steric crowding at the water binding site in amides as compared to carboxylate analogues. Substitution of the third acetate of DTPA5- with an amide, however, results in a less pronounced decrease in kex than substitution of the first two acetates. The activation volumes derived from a variable pressure (17)O NMR study prove a dissociative interchange and a limiting dissociative mechanism for [Gd(L2)(H2O

  12. Biosynthesis of the major brain gangliosides GD1a and GT1b

    PubMed Central

    Sturgill, Elizabeth R; Aoki, Kazuhiro; Lopez, Pablo HH; Colacurcio, Daniel; Vajn, Katarina; Lorenzini, Ileana; Majić, Senka; Yang, Won Ho; Heffer, Marija; Tiemeyer, Michael; Marth, Jamey D; Schnaar, Ronald L

    2012-01-01

    Gangliosides—sialylated glycosphingolipids—are the major glycoconjugates of nerve cells. The same four structures—GM1, GD1a, GD1b and GT1b—comprise the great majority of gangliosides in mammalian brains. They share a common tetrasaccharide core (Galβ1–3GalNAcβ1-4Galβ1-4Glcβ1-1′Cer) with one or two sialic acids on the internal galactose and zero (GM1 and GD1b) or one (GD1a and GT1b) α2–3-linked sialic acid on the terminal galactose. Whereas the genes responsible for the sialylation of the internal galactose are known, those responsible for terminal sialylation have not been established in vivo. We report that St3gal2 and St3gal3 are responsible for nearly all the terminal sialylation of brain gangliosides in the mouse. When brain ganglioside expression was analyzed in adult St3gal1-, St3gal2-, St3gal3- and St3gal4-null mice, only St3gal2-null mice differed significantly from wild type, expressing half the normal amount of GD1a and GT1b. St3gal1/2-double-null mice were no different than St3gal2-single-null mice; however, St3gal2/3-double-null mice were >95% depleted in gangliosides GD1a and GT1b. Total ganglioside expression (lipid-bound sialic acid) in the brains of St3gal2/3-double-null mice was equivalent to that in wild-type mice, whereas total protein sialylation was reduced by half. St3gal2/3-double-null mice were small, weak and short lived. They were half the weight of wild-type mice at weaning and displayed early hindlimb dysreflexia. We conclude that the St3gal2 and St3gal3 gene products (ST3Gal-II and ST3Gal-III sialyltransferases) are largely responsible for ganglioside terminal α2-3 sialylation in the brain, synthesizing the major brain gangliosides GD1a and GT1b. PMID:22735313

  13. New Insights on Non-Enzymatic Oxidation of Ganglioside GM1 Using Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Couto, Daniela; Melo, Tânia; Maciel, Elisabete; Campos, Ana; Alves, Eliana; Guedes, Sofia; Domingues, M. Rosário M.; Domingues, Pedro

    2016-12-01

    Gangliosides are acidic glycosphingolipids that are present in cell membranes and lipid raft domains, being particularly abundant in central nervous systems. They participate in modulating cell membrane properties, cell-cell recognition, cell regulation, and signaling. Disturbance in ganglioside metabolism has been correlated with the development of diseases, such as neurodegenerative diseases, and in inflammation. Both conditions are associated with an increased production of reactive oxidation species (ROS) that can induce changes in the structure of biomolecules, including lipids, leading to the loss or modification of their function. Oxidized phospholipids are usually involved in chronic diseases and inflammation. However, knowledge regarding oxidation of gangliosides is scarce. In order to evaluate the effect of ROS in gangliosides, an in vitro biomimetic model system was used to study the susceptibility of GM1 (Neu5Ac α2-3(Gal β1-3GalNAc β1-4)Gal β1-4Glc β1Cer) to undergo oxidative modifications. Oxidation of GM1 under Fenton reaction conditions was monitored using high resolution electrospray ionization-mass spectrometry (ESI-MS) and tandem mass spectrometry (ESI-MS/MS). Upon oxidation, GM1 underwent oxidative cleavages in the carbohydrate chain, leading to the formation of other gangliosides GM2 (GalNAcβ1-4Gal(Neu5Acα2-3)1-4Glcβ1Cer), GM3 (Neu5Acα2-3Galβ1-4Glcβ1Cer), asialo-GM1 (Gal β1-3GalNAc β1-4Gal β1-4Glc β1Cer), asialo-GM2 (GalNAc β1-4Gal β1-4Glc β1Cer), of the small glycolipids lactosylceramide (LacCer), glucosylceramide (GlcCer), and of ceramide (Cer). In addition, oxygenated GM1 and GM2 (as keto and hydroxy derivatives), glycans, oxidized glycans, and oxidized ceramides were also identified. Nonenzymatic oxidation of GM1 under oxidative stress contributes to the generation of other gangliosides that may participate in the imbalance of gangliosides metabolism in vivo, through uncontrolled enzymatic pathways and, consequently, play

  14. Glycosylated SV2 and Gangliosides as Dual Receptors for Botulinum Neurotoxin Serotype F

    SciTech Connect

    Fu, Zhuji; Chen, Chen; Barbieri, Joseph T.; Kim, Jung-Ja P.; Baldwin, Michael R.

    2010-02-22

    Botulinum neurotoxin causes rapid flaccid paralysis through the inhibition of acetylcholine release at the neuromuscular junction. The seven BoNT serotypes (A-G) have been proposed to bind motor neurons via ganglioside-protein dual receptors. To date, the structure-function properties of BoNT/F host receptor interactions have not been resolved. Here, we report the crystal structures of the receptor binding domains (HCR) of BoNT/A and BoNT/F and the characterization of the dual receptors for BoNT/F. The overall polypeptide fold of HCR/A is essentially identical to the receptor binding domain of the BoNT/A holotoxin, and the structure of HCR/F is very similar to that of HCR/A, except for two regions implicated in neuronal binding. Solid phase array analysis identified two HCR/F binding glycans: ganglioside GD1a and oligosaccharides containing an N-acetyllactosamine core. Using affinity chromatography, HCR/F bound native synaptic vesicle glycoproteins as part of a protein complex. Deglycosylation of glycoproteins using {alpha}(1-3,4)-fucosidase, endo-{beta}-galactosidase, and PNGase F disrupted the interaction with HCR/F, while the binding of HCR/B to its cognate receptor, synaptotagmin I, was unaffected. These data indicate that the HCR/F binds synaptic vesicle glycoproteins through the keratan sulfate moiety of SV2. The interaction of HCR/F with gangliosides was also investigated. HCR/F bound specifically to gangliosides that contain {alpha}2,3-linked sialic acid on the terminal galactose of a neutral saccharide core (binding order GT1b = GD1a GM3; no binding to GD1b and GM1a). Mutations within the putative ganglioside binding pocket of HCR/F decreased binding to gangliosides, synaptic vesicle protein complexes, and primary rat hippocampal neurons. Thus, BoNT/F neuronal discrimination involves the recognition of ganglioside and protein (glycosylated SV2) carbohydrate moieties, providing a structural basis for the high affinity and specificity of BoNT/F for neurons.

  15. Early Supplementation of Phospholipids and Gangliosides Affects Brain and Cognitive Development in Neonatal Piglets123

    PubMed Central

    Liu, Hongnan; Radlowski, Emily C; Conrad, Matthew S; Li, Yao; Dilger, Ryan N; Johnson, Rodney W

    2014-01-01

    Background: Because human breast milk is a rich source of phospholipids and gangliosides and breastfed infants have improved learning compared with formula-fed infants, the importance of dietary phospholipids and gangliosides for brain development is of interest. Objective: We sought to determine the effects of phospholipids and gangliosides on brain and cognitive development. Methods: Male and female piglets from multiple litters were artificially reared and fed formula containing 0% (control), 0.8%, or 2.5% Lacprodan PL-20 (PL-20; Arla Foods Ingredients), a phospholipid/ganglioside supplement, from postnatal day (PD) 2 to PD28. Beginning on PD14, performance in a spatial T-maze task was assessed. At PD28, brain MRI data were acquired and piglets were killed to obtain hippocampal tissue for metabolic profiling. Results: Diet affected maze performance, with piglets that were fed 0.8% and 2.5% PL-20 making fewer errors than control piglets (80% vs. 75% correct on average; P < 0.05) and taking less time to make a choice (3 vs. 5 s/trial; P < 0.01). Mean brain weight was 5% higher for piglets fed 0.8% and 2.5% PL-20 (P < 0.05) than control piglets, and voxel-based morphometry revealed multiple brain areas with greater volumes and more gray and white matter in piglets fed 0.8% and 2.5% PL-20 than in control piglets. Metabolic profiling of hippocampal tissue revealed that multiple phosphatidylcholine-related metabolites were altered by diet. Conclusion: In summary, dietary phospholipids and gangliosides improved spatial learning and affected brain growth and composition in neonatal piglets. PMID:25411030

  16. High-efficiency Watt-level picosecond pulse generation based on Yb:Gd3AlxGa5-xO12 crystal

    NASA Astrophysics Data System (ADS)

    Li, Yanbin; Jia, Zhitai; Lou, Fei; Zhang, Baitao; He, Jingliang; Tao, Xutang

    2015-07-01

    A diode-pumped passively mode-locked Yb3+:Gd3Al0.5Ga4.5O12 (Yb:GAGG) laser has been investigated by using a semiconductor saturable absorber mirror (SESAM) for the first time. Pulses with duration of 1.6 ps were produced at the central wavelength of 1027.8 nm. At the absorbed pump power of 8.4 W, the maximum average output power of 1.02 W was obtained with the repetition rate of 45 MHz. The corresponding single pulse energy and the peak power were calculated to be 22.7 nJ and 14.2 kW, respectively.

  17. High-efficiency femtosecond Yb:Gd3Al(0.5)Ga(4.5)O12 mode-locked laser based on reduced graphene oxide.

    PubMed

    Lou, Fei; Cui, Liang; Li, Yan-Bin; Hou, Jia; He, Jing-Liang; Jia, Zhi-Tai; Liu, Jing-Quan; Zhang, Bai-Tao; Yang, Ke-Jian; Wang, Zhao-Wei; Tao, Xu-Tang

    2013-10-15

    A diode-pumped Yb-doped Gd(3)Al(0.5)Ga(4.5)O(12) mode-locked bulk laser based on chemically reduced graphene oxide (RGO) has been demonstrated for the first time to our best knowledge. Pulses with duration of 643 fs were produced at the central wavelength of 1041.1 nm. A maximum average output power of 0.8 W was obtained from the RGO mode-locked laser, corresponding to a slope efficiency of 20.1% and a peak power of 27.6 kW. The results indicate that RGO is suitable for obtaining high-power and high-efficiency ultrafast lasers.

  18. Trap depth and color variation of Ce3+-Cr3+ co-doped Gd3(Al,Ga)5O12 garnet persistent phosphors

    NASA Astrophysics Data System (ADS)

    Asami, Kazuki; Ueda, Jumpei; Tanabe, Setsuhisa

    2016-12-01

    Persistent luminescent properties in Ce3+-Cr3+ codoped Gd3Al5-xGaxO12 garnet (GAGG:Ce-Cr) solid solution have been investigated. The persistent luminescent color is shifted from orange to yellowish green with increasing Ga content because Ce3+: 5d level splitting becomes much weaker. The depth of electron trap introduced by Cr codoping was estimated from the intense thermoluminescence glow peak by the initial rise method. The trap depth decreases from 0.56 eV to 0.29 eV with increasing Ga content. The shift can be explained by downshift of bottom of conduction band. From the persistent luminescence decay curve measurement after ceasing 450 nm blue illumination, the samples with x = 2.5 exhibited the longest persistent luminescence for 405 min until the luminance becomes 2 mcd/m2 in GAGG:Ce-Cr phosphors.

  19. Specific suppression of major histocompatibility complex class I and class II genes in astrocytes by brain-enriched gangliosides

    PubMed Central

    1993-01-01

    The effect of brain-enriched gangliosides on constitutive and cytokine- inducible expression of major histocompatibility complex (MHC) class I and II genes in cultured astrocytes was studied. Before treatment with gangliosides, astrocytes expressed constitutive MHC class I but not class II molecules, however, the expression of both MHC class I and II cell surface molecules on astrocytes was induced to high levels by interferon gamma (IFN-gamma). Constitutive and IFN-gamma-inducible expression of MHC class I and II molecules was suppressed by treatment of astrocytes with exogenous bovine brain gangliosides in a dose- dependent manner. Constitutive and induced MHC class I and II mRNA levels were also suppressed by gangliosides, indicating control through transcriptional mechanisms. This was consistent with the ability of gangliosides to suppress the binding activity of transcription factors, especially NF-kappa B-like binding activity, important for the expression of both MHC class I and II genes. These studies may be important for understanding mechanisms of central nervous system (CNS)- specific regulation of major histocompatibility molecules in neuroectodermal cells and the role of gangliosides in regulating MHC- restricted antiviral and autoimmune responses within the CNS. PMID:8376939

  20. Effect of tin ions on enhancing the intensity of narrow luminescence line at 311 nm of Gd3+ ions in Li2Osbnd PbOsbnd P2O5 glass system

    NASA Astrophysics Data System (ADS)

    Gandhi, Y.; Rajanikanth, P.; Sundara Rao, M.; Ravi Kumar, V.; Veeraiah, N.; Piasecki, M.

    2016-07-01

    This study is mainly focused on enriching the UVB 311 narrow emission band of Gd3+ ions in Li2Osbnd PbOsbnd P2O5 glasses doped with 1.0 mol% of Gd2O3 and mixed with different concentrations of SnO2 (0-7.0 mol%). The emission spectra SnO2 free glasses exhibited intense narrow UVB band at 311 nm due to 6P7/2 → 8S7/2 transition of Gd3+ ions when excited at 273 nm. The intensity of this band is found to be enhanced nearly four times when the glasses are mixed with 3.0 mol% of SnO2. The reasons for this enhancement have been explored in the light of energy transfer from Sn4+ to Gd3+ ions with the help of rate equations. The declustering of Gd3+ ions (that reduce cross relaxation losses) by tin ions is also found to the other reason for such enrichment. The 311 nm radiation is an efficient in the treatment of various skin diseases and currently it is one of the most desirable and commonly utilised UVB in the construction of phototherapy devices.

  1. Effects of Ganglioside on Working Memory and the Default Mode Network in Individuals with Subjective Cognitive Impairment: A Randomized Controlled Trial.

    PubMed

    Jeon, Yujin; Kim, Binna; Kim, Jieun E; Kim, Bori R; Ban, Soonhyun; Jeong, Jee Hyang; Kwon, Oran; Rhie, Sandy Jeong; Ahn, Chang-Won; Kim, Jong-Hoon; Jung, Sung Ug; Park, Soo-Hyun; Lyoo, In Kyoon; Yoon, Sujung

    2016-01-01

    This randomized, double-blind, placebo-controlled trial examined whether the administration of ganglioside, an active ingredient of deer bone extract, can improve working memory performance by increasing gray matter volume and functional connectivity in the default mode network (DMN) in individuals with subjective cognitive impairment. Seventy-five individuals with subjective cognitive impairment were chosen to receive either ganglioside (330[Formula: see text][Formula: see text]g/day or 660[Formula: see text][Formula: see text]g/day) or a placebo for 8 weeks. Changes in working memory performance with treatment of either ganglioside or placebo were assessed as cognitive outcome measures. Using voxel-based morphometry and functional connectivity analyses, changes in gray matter volume and functional connectivity in the DMN were also assessed as brain outcome measures. Improvement in working memory performance was greater in the ganglioside group than in the placebo group. The ganglioside group, relative to the placebo group, showed greater increases in gray matter volume and functional connectivity in the DMN. A significant relationship between increased functional connectivity of the precuneus and improved working memory performance was observed in the ganglioside group. The current findings suggest that ganglioside has cognitive-enhancing effects in individuals with subjective cognitive impairment. Ganglioside-induced increases in gray matter volume and functional connectivity in the DMN may partly be responsible for the potential nootropic effects of ganglioside. The clinical trial was registered with ClinicalTrials.gov (identifier: NCT02379481).

  2. Erythropoietin enhances nerve repair in anti-ganglioside antibody-mediated models of immune neuropathy.

    PubMed

    Zhang, Gang; Lehmann, Helmar C; Bogdanova, Nataliia; Gao, Tong; Zhang, Jiangyang; Sheikh, Kazim A

    2011-01-01

    Guillain-Barré syndrome (GBS) is a monophasic immune neuropathic disorder in which a significant proportion of patients have incomplete recovery. The patients with incomplete recovery almost always have some degree of failure of axon regeneration and target reinnervation. Anti-ganglioside antibodies (Abs) are the most commonly recognized autoimmune markers in all forms of GBS and specific Abs are associated with the slow/poor recovery. We recently demonstrated that specific anti-ganglioside Abs inhibit axonal regeneration and nerve repair in preclinical models by activation of small GTPase RhoA and its downstream effectors. The objective of this study was to determine whether erythropoietin (EPO), a pleiotropic cytokine with neuroprotective and neurotrophic properties, enhances nerve regeneration in preclinical cell culture and animal models of autoimmune neuropathy/nerve repair generated with monoclonal and patient derived Abs. Primary neuronal cultures and a standardized sciatic crush nerve model were used to assess the efficacy of EPO in reversing inhibitory effects of anti-ganglioside Abs on nerve repair. We found that EPO completely reversed the inhibitory effects of anti-ganglioside Abs on axon regeneration in cell culture models and significantly improved nerve regeneration/repair in an animal model. Moreover, EPO-induced proregenerative effects in nerve cells are through EPO receptors and Janus kinase 2/Signal transducer and activator of transcription 5 pathway and not via early direct modulation of small GTPase RhoA. These preclinical studies indicate that EPO is a viable candidate drug to develop further for neuroprotection and enhancing nerve repair in patients with GBS.

  3. Dysfunction of nodes of Ranvier: a mechanism for anti-ganglioside antibody-mediated neuropathies

    PubMed Central

    Susuki, Keiichiro; Yuki, Nobuhiro; Schafer, Dorothy P.; Hirata, Koichi; Zhang, Gang; Funakoshi, Kei; Rasband, Matthew N.

    2011-01-01

    Autoantibodies against gangliosides GM1 or GD1a are associated with acute motor axonal neuropathy (AMAN) and acute motor-sensory axonal neuropathy (AMSAN), whereas antibodies to GD1b ganglioside are detected in acute sensory ataxic neuropathy (ASAN). These neuropathies have been proposed to be closely related and comprise a continuous spectrum, although the underlying mechanisms, especially for sensory nerve involvement, are still unclear. Antibodies to GM1 and GD1a have been proposed to disrupt the nodes of Ranvier in motor nerves via complement pathway. We hypothesized that the disruption of nodes of Ranvier is a common mechanism whereby various anti-ganglioside antibodies found in these neuropathies lead to nervous system dysfunction. Here, we show that the IgG monoclonal anti-GD1a/GT1b antibody injected into rat sciatic nerves caused deposition of IgG and complement products on the nodal axolemma and disrupted clusters of nodal and paranodal molecules predominantly in motor nerves, and induced early reversible motor nerve conduction block. Injection of IgG monoclonal anti-GD1b antibody induced nodal disruption predominantly in sensory nerves. In an ASAN rabbit model associated with IgG anti-GD1b antibodies, complement-mediated nodal disruption was observed predominantly in sensory nerves. In an AMAN rabbit model associated with IgG anti-GM1 antibodies, complement attack of nodes was found primarily in motor nerves, but occasionally in sensory nerves as well. Periaxonal macrophages and axonal degeneration were observed in dorsal roots from ASAN rabbits and AMAN rabbits. Thus, nodal disruption may be a common mechanism in immune-mediated neuropathies associated with autoantibodies to gangliosides GM1, GD1a, or GD1b, providing an explanation for the continuous spectrum of AMAN, AMSAN, and ASAN. PMID:22178332

  4. Anti-ganglioside anti-idiotypic vaccination: more than molecular mimicry

    PubMed Central

    Vázquez, Ana M. H.; Rodrèguez-Zhurbenko, Nely; López, Ana M. V.

    2012-01-01

    Surgery, chemotherapy, and radiation therapy are standard modalities for cancer treatment, but the effectiveness of these treatments has reached a plateau. Thus, other strategies are being explored to combine with the current treatment paradigms in order to reach better clinical results. One of these approaches is the active immunotherapy based on the induction of anti-tumor responses by anti-idiotypic vaccination. This approach arose from Jerne’s idiotypic network theory, which postulates that B lymphocytes forms a functional network, with a role in the establishment of the immune repertoires, in the regulation of natural antibody production and even in the establishment of natural tolerance. Due to the large potential diversity of the immunoglobulin variable regions, the idiotypes repertoire can mimic the universe of self and foreign epitopes, even those of non-protein nature, like gangliosides. Gangliosides are sialic acid-containing glycolipids that have been considered attractive targets for cancer immunotherapy, based on the qualitative and quantitative changes they suffer during malignant transformation and due to their importance for tumor biology. Although any idiotype could be able to mimic any antigen, only those related to antigens involved in functions relevant for organism homeostasis, and that in consequence has been fixed by evolution, would be able not only to mimic, but also to activate the idiotypic cascades related with the nominal antigen. The present review updates the results, failures and hopes, obtained with ganglioside mimicking anti-idiotypic antibodies and presents evidences of the existence of a natural response against gangliosides, suggesting that these glycolipids could be idiotypically relevant antigens. PMID:23181219

  5. Early growth and development impairments in patients with ganglioside GM3 synthase deficiency.

    PubMed

    Wang, H; Wang, A; Wang, D; Bright, A; Sency, V; Zhou, A; Xin, B

    2016-05-01

    Ganglioside GM3 synthase is a key enzyme involved in the biosynthesis of gangliosides. GM3 synthase deficiency (GSD) causes a complete absence of GM3 and all downstream biosynthetic derivatives. The individuals affected by this disorder manifest severe irritability, intractable seizures and profound intellectual disability. However, we have found that most newborns seem symptom-free for a period of time after birth. In order to further understand the onset of the disease, we investigated the early growth and development of patients with this condition through this study. We compared 37 affected individuals with their normal siblings and revealed that all children with GSD had relatively normal intrauterine growth and development, as their weight, length and head circumference were similar to their normal siblings at birth. However, the disease progresses quickly after birth and causes significant constitutional impairments of growth and development by 6 months of age. Neither breastfeeding nor gastrostomy tube placement made significant difference on growth and development as all groups of patients showed the similar pattern. We conclude that GSD causes significant postnatal growth and developmental impairments and the amount of gangliosides in breast milk and general nutritional intervention do not seem to alter these outcomes.

  6. A Novel Approach for Ganglioside Structural Analysis Based on Electrospray Multiple-Stage Mass Spectrometry

    PubMed Central

    Zamfir, Alina D.; Vukelić, Željka; Schneider, Andrea; Sisu, Eugen; Dinca, Nicolae; Ingendoh, Arnd

    2007-01-01

    A powerful method for detailed structural analysis based on electrospray ionization high-capacity ion-trap multiple-stage mass spectrometry (MS) is for the first time introduced in glycolipidomics. The method was optimized for accurate structural elucidation of human brain gangliosides and specifically applied to normal adult human hippocampus-associated structures. The multiple-stage MS experiments reported here allowed for a complete structural characterization of the oligosaccharide moiety of a GM1 ganglioside species. This was achieved by elucidating the sequence and identification of the GM1a structural isomer from the sialic acid attachment site at the neutral oligosaccharide chain. Moreover, the determination of the d18:1/18:0 sphingoid base/fatty acid composition of the ceramide moiety could be confirmed by this method. The novel protocol developed here proves high potential for rapid, reliable, and reproducible investigation of complex lipid-linked carbohydrates such as polysialylated gangliosides or species carrying some other groups that easily cleave off. PMID:17916791

  7. Effects of gangliosides on cell maturation of murine megakaryocytes in a liquid culture system.

    PubMed

    Watanabe, Y; Taniguchi, M; Fukamachi, N; Sakuma, M; Kobayashi, B

    1990-04-01

    Formation of platelet-producing megakaryocytes, the cytoplasm of which showed the terminal stage of cell maturation, heavy granulation and platelet-fields delineated with demarcation membranes, was observed in a short-term culture system, using megakaryocyte-enriched bone marrow cell suspension. Approximately 6-8% of the megakaryocytes changed to the platelet-producing megakaryocytes during 12-hour incubation. In the presence of inhibitors of energy metabolism, formation of the platelet-producing megakaryocytes was inhibited, suggesting that the process is dependent on energy producing systems. Ganglioside GD1a increased both the number of total megakaryocytes and the ratio of the platelet-producing megakaryocytes to total megakaryocytes, while GM1 did not influence the number of total megakaryocytes, but increased the ratio. Gangliosides GM2, GM3 and GD1b showed little effect on either the number of total megakaryocytes or the ratio. The results suggest that ganglioside GD1a stimulates at least two steps of megakaryocyte maturation, the change of megakaryocytic progenitors to megakaryocytes and the subsequent maturation of megakaryocytes to the platelet-producing megakaryocytes, while GM1 stimulates only the latter step of the maturation.

  8. Cholera toxin binding affinity and specificity for gangliosides determined by surface plasmon resonance

    SciTech Connect

    Kuziemko, G.M.; Stroh, M.; Stevens, R.C. |

    1996-05-21

    The present study determines the affinity of cholera toxin for the ganglioside series GM1, GM2, GM3, GD1A, GD1B, GT1B, asialo GM1, globotriosyl ceramide, and lactosyl ceramide using real time biospecific interaction analysis (surface plasmon resonance, SPR). SPR shows that cholera toxin preferably binds to gangliosides in the following sequence: GM1 > GM2 > GD1A > GM3 > GT1B > GD1B > asialo-GM1. The measured binding affinity of cholera toxin for the ganglioside sequence ranges from 4.61 {times} 10{sup {minus}12} M for GM1 to 1.88 {times} 10{sup {minus}10} M for asialo GM1. The picomolar values obtained by surface plasmon resonance are similar to K{sub d} values determined with whole-cell binding assays. Both whole-cell assays ans SPR measurements on synthetic membranes are higher than free solution measurements by several orders of magnitude. This difference may be caused by the effects of avidity and charged lipid head-groups, which may play a major role in the binding between cholera toxin, the receptor, and the membrane surface. The primary difference between free solution binding studies and surface plasmon resonance studies is that the latter technique is performed on surfaces resembling the cell membrane. Surface plasmon resonance has the further advantage of measuring apparent kinetic association and dissociation rates in real time, providing direct information about binding events at the membrane surface. 34 refs., 8 figs., 2 tabs.

  9. Insights into the immunogenetic basis of two ganglioside-associated idiotypic networks.

    PubMed

    Rodríguez, Mabel; Roque-Navarro, Lourdes; López-Requena, Alejandro; Moreno, Ernesto; Mateo de Acosta, Cristina; Pérez, Rolando; María Vázquez, Ana

    2007-01-01

    The heavy-chain variable regions (VH) from 14F7 MAb, an IgG1 antibody specific for GM3(NeuGc) ganglioside, and its anti-idiotype, the 4G9 MAb, were cloned and sequenced. Comparison with previously reported sequences showed that VH 14F7 belongs to the J558(VHI) gene family and that it is highly mutated. VH 4G9 belongs to the Q52(VHII) gene family. The HCDR3 14F7 sequence contains three basic residues that could be involved in the binding to 4G9 MAb, which bears acidic residues in its HCDR3. Studies performed in the syngeneic model showed that 14F7 MAb requires both coupling to KLH and the use of Freund's adjuvant to induce an effective anti-idiotypic IgG (Ab2) response. In contrast, P3 MAb, a germline gene-encoded Ab1 that also recognizes the GM3(NeuGc) ganglioside through a basic motif in its H-CDRs, has been reported to be immunogenic in syngeneic mice, even when injected in saline. In addition, when Leghorn chickens were immunized with 14F7 or P3 MAbs emulsified in Freund's adjuvant, only P3-immunized animals were able to develop antibodies that recognized NeuGc-containing gangliosides, antigens which are not present in the normal tissues of this animal species. This phenomenon could be due to the lack of idiotypic connectivity of 14F7MAb.

  10. Dynamic compression of dense oxide (Gd3Ga5O12) from 0.4 to 2.6 TPa: Universal Hugoniot of fluid metals

    DOE PAGES

    Ozaki, N.; Nellis, W. J.; Mashimo, T.; ...

    2016-05-19

    Materials at high pressures and temperatures are of great current interest for warm dense matter physics, planetary sciences, and inertial fusion energy research. Shock-compression equation-of-state data and optical reflectivities of the fluid dense oxide, Gd3Ga5O12 (GGG), were measured at extremely high pressures up to 2.6 TPa (26 Mbar) generated by high-power laser irradiation and magnetically-driven hypervelocity impacts. Above 0.75 TPa, the GGG Hugoniot data approach/reach a universal linear line of fluid metals, and the optical reflectivity most likely reaches a constant value indicating that GGG undergoes a crossover from fluid semiconductor to poor metal with minimum metallic conductivity (MMC). Thesemore » results suggest that most fluid compounds, e.g., strong planetary oxides, reach a common state on the universal Hugoniot of fluid metals (UHFM) with MMC at sufficiently extreme pressures and temperatures. Lastly, the systematic behaviors of warm dense fluid would be useful benchmarks for developing theoretical equation-of-state and transport models in the warm dense matter regime in determining computational predictions.« less

  11. Control of Nd and Cr concentrations in Nd,Cr : Gd 3Ga 5O 12 single crystals grown by Czochralski method

    NASA Astrophysics Data System (ADS)

    Keszei, B.; Paitz, J.; Vandlik, J.; Süveges, A.

    2001-06-01

    During the growth process of the Nd,Cr : Gd 3Ga 5O 12 (Nd,Cr : GGG) laser crystals the optimum concentrations of the dopants cannot be realized in axial direction of the crystal at a constant pulling (growth) rate as the effective segregation coefficients ( k) of Nd 3+ and Cr 3+ are not unity and not uniform ( k<1 and k>1, respectively). To solve this problem the dopant concentrations were measured in the crystals grown at different pulling rates by atomic absorption to determine the effective and equilibrium segregation coefficients and the ratio of the boundary layer thickness and diffusion coefficients. In the light of these parameters we suggest a pulling (growth) rate program as a function of the fraction of the crystallized melt leading to the smallest concentration variation of the dopants along the length axis of the crystals. The variation of Nd 3+ concentration in the crystal reduced from 35% to 19% while the laser efficiency increased by 15-20% by this method.

  12. 2 inch size Czochralski growth and scintillation properties of Li+ co-doped Ce:Gd3Ga3Al2O12

    NASA Astrophysics Data System (ADS)

    Kamada, Kei; Shoji, Yasuhiro; Kochurikhin, Vladimir V.; Yoshino, Masao; Okumura, Satoshi; Yamamoto, Seiichi; Yeom, Jung Yeol; Kurosawa, Shunsuke; Yokota, Yuui; Ohashi, Yuji; Nikl, Martin; Yoshino, Masao; Yoshikawa, Akira

    2017-03-01

    The 2 inch size Li 0.15 and 1.35 mol% co-doped Ce:Gd3Al2Ga3O12 single crystals were prepared by the Czochralski (Cz) method. Absorption and luminescence spectra were measured together with several other scintillation characteristics, namely the scintillation decay and light yield to reveal the effect of Li co-doping. Ce4+ CT absorption below 350 nm is clearly enhanced by Li co-doping as same as divalent ions co-doping. By 1.35 at.% Li co-doping, light yield was decrease to 88% of the Ce: GAGG standard and decay time was accelerated to 34.3ns 21.0%, 84.6ns 68.7%, 480ns 10.3%. The timing resolution measurement for a pair of 3 × 3 × 3mm3 size Li,Ce:GAGG scintillator crystals was performed using Si-PMs and the timing resolution of the 1.35 at.% Li co-doped Ce:GAGG was 218ps.

  13. Continuous wave and passively Q-switched laser performance of Nd:LuxGd3-xGa5O12 crystal at 1062 nm

    NASA Astrophysics Data System (ADS)

    Fu, X. W.; Jia, Z. T.; Yang, H.; Li, Y. B.; Yuan, D. S.; Zhang, B. T.; Dong, C. M.; He, J. L.; Tao, X. T.

    2012-12-01

    Continuous wave (CW) and passively Q-switched (PQS) laser properties at 1062 nm of the Nd:LuxGd3-xGa5O12 (Nd:LGGG) disordered crystal have been demonstrated. The doping concentrations of Nd3+ and Lu3+ in the as obtained crystal were measured to be 0.96 and 0.66 at.%, respectively. In the CW regime, the output power of 9.73 W was obtained with an optical-to-optical efficiency as high as 60.7% and slope efficiency of 61.2%. During the passively Q-switched operation, the maximum output power of 1.24 W was achieved under the absorbed pump power of 6.86 W. The maximum peak power of 14.20 kW and single pulse energy of 148 μJ were obtained with the Toc = 10% under the absorbed pump power of 6.36 W. The results are much better than those obtained with Nd:LGGG crystal doped with 13.6 at.% Lu3+ and 0.53 at.% Nd3+ ions.

  14. Gd3+-DTPA-bis (N-methylamine) - anionic linear globular Dendrimer-G1; a more efficient MRI contrast media.

    PubMed

    Ghalandarlaki, N; Mohammadi, T D; Agha Babaei, R; Tabasi, M A; Keyhanvar, P; Mehravi, B; Yaghmaei, P; Cohan, R A; Ardestani, M S

    2014-02-01

    By advancing of molecular imaging techniques, magnetic resonance imaging (MRI) is becoming an increasingly important tool in early diagnosis. Researchers have found new ways to increase contrast of MRI images.Therefore some types of drug known as contrast media are produced. Contrast media improve the visibility of internal body structures in MRI images. Gadodiamide (Omniscan®) is one of these contrast media which is produced commercially and used clinically. In this study Gadodiamide was first synthesized and then qualitative and quantitative methods were carried out to ensure the proper synthesis of this drug then to increase the efficiency of this contrast medium use dendrimer that is one kind of nano particle. This dendrimer has a polyethylene glycol (PEG) core and citric acid branches. After dendrimer attached to Gadodiamide to ensure the proper efficient connection between them the stability studies were carried out and cytotoxicity of the drug was evaluated. Finally, after ensuring the non-toxicity of the drug, in vivo studies (injected into mice) MR imaging was performed to examine the impact of synthesis drug on the resolution of image.The result obtained from this study demonstrated that the attachment of Gadodiamide to dendrimer reduces its cytotoxicity and also improved resolution of image. Also the new contrast media (Gd3+-DTPA- bis [N-methylamine] - Dendrimer) - unlike Omniscan® - is biodegradable and able to enter the HEPG2 cell line. The results confirm the hypothesis that using dendrimer to synthesize this new nano contrast medium increases its effectiveness.

  15. A Eu3+/Gd3+-EDTA-doped structurally controllable hollow mesoporous carbon for improving the oral bioavailability of insoluble drugs and in vivo tracing

    NASA Astrophysics Data System (ADS)

    Liu, Jia; Zhao, Yating; Cui, Yu; Yue, Yang; Gao, Yikun; Zhao, Qinfu; Liu, Jie; Wang, Siling

    2016-08-01

    A structurally controllable fluorescence-labeled hollow mesoporous carbon (HMC) was simply prepared to improve the oral bioavailability of insoluble drugs and further trace their delivery process in vivo. The hollow structure was derived from an inverse replica process using mesoporous silica as a template and the fluorescent label was prepared by doping the carboxylated HMC with a confinement of Eu3+/Gd3+-EDTA. The physicochemical properties of the composites were systematically characterized by transmission electron microscopy, Fourier transform infrared spectroscopy and photoluminescence spectra tests prior to studying their effects on drug-release behavior and biodistribution. As a result, the thickness of the carrier’s shell was adjusted from 70 nm to 130 nm and the maximum drug loading was up to 73.6%. The model drug carvedilol (CAR) showed sustained release behavior compared to CAR commercial capsules, and the dissolution rate slowed down as the shells got thicker. AUC0-48h and Tmax were enlarged 2.2 and 6.5 fold, respectively, which demonstrated that oral bioavailability was successfully improved. Bioimaging tests showed that the novel carbon vehicle had a long residence time in the gastrointestinal tract. In short, the newly designed HMC is a promising drug carrier for both oral bioavailability improvement and in vivo tracing.

  16. Spin-phonon and lattice contributions to the ground-state splitting of Gd3+ and Eu2+ in scheelite crystals

    NASA Astrophysics Data System (ADS)

    Gorlov, A. D.

    2015-07-01

    The EPR spectra of Gd3+ in CaWO4 single crystals have been studied at temperatures T = 1.8, 4.2, and 114-300 K, and the temperature dependence of the parameters b {/n m } ( T) of the spin Hamiltonian has been found. The behavior of b {2/0}( T) has been analyzed. The spin-phonon and static lattice contributions b {2/0}( F) and b {2/0}( L) to b {2/0}( T) have been revealed. For this purpose, the variation of b {2/0}( L) has been calculated taking into account the thermal shifts of oxygen ions in CaWO4. Similar analysis has been carried out for CaWO4: Eu2+ based on the EPR data of other authors (Bronstein, Voterra and Harvey, Kiefte). It has been shown that at b {2/0}( F) > 0, the variation of b {2/0}( F) as a function of T for these impurity centers is described well by the Pfister model and a sign change of b {2/0}( T) for Eu2+ is determined by thermal expansion of the lattice.

  17. Real-time tracking of dissociation of hyperpolarized 89Y-DTPA: a model for degradation of open-chain Gd3+ MRI contrast agents

    NASA Astrophysics Data System (ADS)

    Ferguson, Sarah; Niedbalski, Peter; Parish, Christopher; Kiswandhi, Andhika; Kovacs, Zoltan; Lumata, Lloyd

    Gadolinium (Gd) complexes are widely used relaxation-based clinical contrast agents in magnetic resonance imaging (MRI). Gd-based MRI contrast agents with open-chain ligand such as Gd-DTPA, commercially known as magnevist, are less stable compared to Gd complexes with macrocyclic ligands such as GdDOTA (Dotarem). The dissociation of Gd-DPTA into Gd ion and DTPA ligand under certain biological conditions such as high zinc levels can potentially cause kidney damage. Since Gd is paramagnetic, direct NMR detection of the Gd-DTPA dissociation is quite challenging due to ultra-short relaxation times. In this work, we have investigated Y-DTPA as a model for Gd-DPTA dissociation under high zinc content solutions. Using dissolution dynamic nuclear polarization (DNP), the 89Y NMR signal is amplified by several thousand-fold. Due to the the relatively long T1 relaxation time of 89Y which translates to hyperpolarization lifetime of several minutes, the dissociation of Y-DTPA can be tracked in real-time by hyperpolarized 89Y NMR spectroscopy. Dissociation kinetic rates and implications on the degradation of open-chain Gd3+ MRI contrast agents will be discussed. This work was supported by the U.S. Department of Defense Award Number W81XWH-14-1-0048 and by the Robert A. Welch Foundation research Grant Number AT-1877.

  18. Dynamic compression of dense oxide (Gd3Ga5O12) from 0.4 to 2.6 TPa: Universal Hugoniot of fluid metals

    PubMed Central

    Ozaki, N.; Nellis, W. J.; Mashimo, T.; Ramzan, M.; Ahuja, R.; Kaewmaraya, T.; Kimura, T.; Knudson, M.; Miyanishi, K.; Sakawa, Y.; Sano, T.; Kodama, R.

    2016-01-01

    Materials at high pressures and temperatures are of great current interest for warm dense matter physics, planetary sciences, and inertial fusion energy research. Shock-compression equation-of-state data and optical reflectivities of the fluid dense oxide, Gd3Ga5O12 (GGG), were measured at extremely high pressures up to 2.6 TPa (26 Mbar) generated by high-power laser irradiation and magnetically-driven hypervelocity impacts. Above 0.75 TPa, the GGG Hugoniot data approach/reach a universal linear line of fluid metals, and the optical reflectivity most likely reaches a constant value indicating that GGG undergoes a crossover from fluid semiconductor to poor metal with minimum metallic conductivity (MMC). These results suggest that most fluid compounds, e.g., strong planetary oxides, reach a common state on the universal Hugoniot of fluid metals (UHFM) with MMC at sufficiently extreme pressures and temperatures. The systematic behaviors of warm dense fluid would be useful benchmarks for developing theoretical equation-of-state and transport models in the warm dense matter regime in determining computational predictions. PMID:27193942

  19. Radiometric assay for ganglioside sialidase applied to the determination of the enzyme subcellular location in culture human fibroblasts

    SciTech Connect

    Chigorno, V.; Cardace, G.; Pitto, M.; Sonnino, S.; Ghidoni, R.; Tettamanti, G.

    1986-03-01

    A radiometric method for the assay of ganglioside sialidase in cultured human fibroblasts was set up. As substrate, highly radioactive (1.28 Ci/mmol) ganglioside GD/sub 1a/ isotopically tritium-labeled at carbon C-3 of the long chain base was employed; the liberated, and TLC separated (/sup 3/H)GM/sub 1/ was determined by computer-assisted radiochromatoscanning. Under experimental conditions that provided a low and quite acceptable (4-5%) coefficient of variation, the detection limit of the method was 0.1 nmol of liberated GM/sub 1/, using as low as 10 ..mu..g of fibroblast homogenate as protein. The detection limit could be lowered to 0.02-0.03 nmol, adopting conditions that, however, carried a higher analytical error (coefficient of variation over 10%). The content of ganglioside sialidase in human fibroblasts cultured in 75-cm/sup 2/ plastic flasks was 5.8 -/+ 2.5 (SD) nmol liberated GM/sub 1/ h/sup -1/ mg protein/sup -1/. Subfractionation studies performed on fibroblast homogenate showed that the ganglioside sialidase was mainly associated with the light membrane subfraction that was rich in plasma and intracellular membranes. This subfraction displayed almost no sialidase activity on the artificial substrate 4-methylumbelliferyl-D-N-acetylneuraminic acid. A small but measurable ganglioside sialidase activity was also present in the lysosome-enriched subfraction, which contained a very high sialidase activity on the above artificial substrate.

  20. Axonal Guillain-Barré syndrome: relation to anti-ganglioside antibodies and Campylobacter jejuni infection in Japan.

    PubMed

    Ogawara, K; Kuwabara, S; Mori, M; Hattori, T; Koga, M; Yuki, N

    2000-10-01

    To clarify the relations of the axonal form of Guillain-Barré syndrome (GBS) to anti-ganglioside antibodies and Campylobacter jejuni infection, 86 consecutive Japanese GBS patients were studied. Electrodiagnostic criteria showed acute inflammatory demyelinating polyneuropathy in 36% of the patients and acute motor axonal neuropathy (AMAN) in 38%. Frequent anti-ganglioside antibodies were of the IgG class and against GM1 (40%), GD1a (30%), GalNAc-GD1a (17%), and GD1b (21%). Identified infections were C. jejuni (23%), cytomegalovirus (10%), Mycoplasma pneumoniae (6%), and Epstein-Barr virus (3%). There was a strong association between AMAN and IgG antibodies against GM1, GD1a, GalNAc-GD1a, or GD1b. Almost all the patients with at least one of these antibodies had the AMAN pattern or rapid resolution of conduction slowing/block possibly because of early-reversible changes on the axolemma. C. jejuni infection was frequently associated with AMAN or anti-ganglioside antibodies, but more than half of the patients with AMAN or anti-ganglioside antibodies were C. jejuni-negative. These findings suggest that the three phenomena "axonal dysfunctions (AMAN or early-reversible conduction failure)," "IgG antibodies against GM1, GD1a, GalNAc-GD1a, or GD1b," and "C. jejuni infection" are closely associated but that microorganisms other than C. jejuni frequently trigger an anti-ganglioside response and elicit axonal GBS.

  1. Gangliosides are functional nerve cell ligands for myelin-associated glycoprotein (MAG), an inhibitor of nerve regeneration.

    PubMed

    Vyas, Alka A; Patel, Himatkumar V; Fromholt, Susan E; Heffer-Lauc, Marija; Vyas, Kavita A; Dang, Jiyoung; Schachner, Melitta; Schnaar, Ronald L

    2002-06-11

    Myelin-associated glycoprotein (MAG) binds to the nerve cell surface and inhibits nerve regeneration. The nerve cell surface ligand(s) for MAG are not established, although sialic acid-bearing glycans have been implicated. We identify the nerve cell surface gangliosides GD1a and GT1b as specific functional ligands for MAG-mediated inhibition of neurite outgrowth from primary rat cerebellar granule neurons. MAG-mediated neurite outgrowth inhibition is attenuated by (i) neuraminidase treatment of the neurons; (ii) blocking neuronal ganglioside biosynthesis; (iii) genetically modifying the terminal structures of nerve cell surface gangliosides; and (iv) adding highly specific IgG-class antiganglioside mAbs. Furthermore, neurite outgrowth inhibition is mimicked by highly multivalent clustering of GD1a or GT1b by using precomplexed antiganglioside Abs. These data implicate the nerve cell surface gangliosides GD1a and GT1b as functional MAG ligands and suggest that the first step in MAG inhibition is multivalent ganglioside clustering.

  2. Labeling of the retina and optic tectum gangliosides and glycoproteins of chickens in darkness or exposed to light

    SciTech Connect

    Caputto, R.

    1984-01-01

    Chickens that received an intraocular injection of /sup 3/H-ManNAc and were exposed to light had more labeled gangliosides in the retina ganglion cell layer and in the contralateral optic tectum than similarly treated animals that remained in darkness. The effect is not due to the turning on or off of the light. The sialyl groups of sialoglycoproteins showed similar effect but the labeling of proteins in chickens that received /sup 3/H-proline did not show significant differences. So far the effect has been obtained only with retina linked to the optic tectum through the optic nerve. If the nerve is severed the effect disappears. The gangliosides GD1a and GT1 are powerful inhibitors of the GM3-N-acetylgalactosaminyl transferase. The main effect of those gangliosides is expressed when they are linked to the membranes containing the enzyme in such a form that they are not released by washing with water. The hypothesis is advanced that the utilization of gangliosides in the nerve ending during the interneuronal transmission produces a small decrease in their concentration that in turn is transmitted backwards to the neuronal perikarya where it accelerates the synthesis of new gangliosides.

  3. Interaction of Fibroblast Growth Factor-2 (FGF-2) with Free Gangliosides: Biochemical Characterization and Biological Consequences in Endothelial Cell Cultures

    PubMed Central

    Rusnati, Marco; Tanghetti, Elena; Urbinati, Chiara; Tulipano, Giovanni; Marchesini, Sergio; Ziche, Marina; Presta, Marco

    1999-01-01

    Exogenous gangliosides affect the angiogenic activity of fibroblast growth factor-2 (FGF-2), but their mechanism of action has not been elucidated. Here, a possible direct interaction of sialo-glycolipids with FGF-2 has been investigated. Size exclusion chromatography demonstrates that native, but not heat-denatured, 125I-FGF-2 binds to micelles formed by gangliosides GT1b, GD1b, or GM1. Also, gangliosides protect native FGF-2 from trypsin digestion at micromolar concentrations, the order of relative potency being GT1b > GD1b > GM1 = GM2 = sulfatide > GM3 = galactosyl-ceramide, whereas asialo-GM1, neuraminic acid, and N-acetylneuramin-lactose were ineffective. Scatchard plot analysis of the binding data of fluorochrome-labeled GM1 to immobilized FGF-2 indicates that FGF–2/GM1 interaction occurs with a Kd equal to 6 μM. This interaction is inhibited by the sialic acid-binding peptide mastoparan and by the synthetic fragments FGF-2(112–129) and, to a lesser extent, FGF-2(130–155), whereas peptides FGF-2(10–33), FGF-2(39–59), FGF-2(86–96), and the basic peptide HIV-1 Tat(41–60) were ineffective. These data identify the COOH terminus of FGF-2 as a putative ganglioside-binding region. Exogenous gangliosides inhibit the binding of 125I-FGF-2 to high-affinity tyrosine-kinase FGF-receptors (FGFRs) of endothelial GM 7373 cells at micromolar concentrations. The order of relative potency was GT1b > GD1b > GM1 > sulfatide a = sialo-GM1. Accordingly, GT1b,GD1b, GM1, and GM2, but not GM3 and asialo-GM1, prevent the binding of 125I-FGF-2 to a soluble, recombinant form of extracellular FGFR-1. Conversely, the soluble receptor and free heparin inhibit the interaction of fluorochrome-labeled GM1 to immobilized FGF-2. In agreement with their FGFR antagonist activity, free gangliosides inhibit the mitogenic activity exerted by FGF-2 on endothelial cells in the same range of concentrations. Also in this case, GT1b was the most effective among the gangliosides tested

  4. Effect of denervation on a cholinergic-specific ganglioside antigen (Chol-1) present in Torpedo electromotor presynaptic plasma membranes.

    PubMed

    Ferretti, P; Borroni, E

    1984-04-01

    The presence of Chol-1, an antigen identified in the plasma membrane of cholinergic electromotor nerve terminals of Torpedo marmorata, was investigated in Torpedo electric organ after 3, 6, and 9 weeks' denervation. Denervation was monitored by the cessation of stimulus-evoked discharge potentials, by the reduction in nerve terminals seen morphologically, and by the decrease in ACh and ChAT contents. The content of ganglioside-bound sialic acid did not show any appreciable change with time. Some modification of ganglioside pattern on TLC was observed after 9 weeks' denervation. The presence of Chol-1 after denervation was assayed by its activity in inhibiting the selective complement-induced lysis of the cholinergic subpopulation of guinea pig cortical synaptosome which is mediated by the anti-Chol-1 antiserum. Denervation did not affect Chol-1 immunoreactivity although it did alter the distribution of the immunoreactivity among gangliosides. The possible significance of the results is discussed.

  5. Constituents of ophiuroidea. 1. Isolation and structure of three ganglioside molecular species from the brittle star Ophiocoma scolopendrina.

    PubMed

    Inagaki, M; Shibai, M; Isobe, R; Higuchi, R

    2001-12-01

    Three ganglioside molecular species, OSG-0 (1), OSG-1 (2), and OSG-2 (3) have been obtained from the polar lipid fraction of the chloroform/methanol extract of the brittle star Ophiocoma scolopendrina. The structures of these gangliosides have been determined on the basis of chemical and spectroscopic evidence as 1-O-[(N-glycolyl-alpha-D-neuraminosyl)-(2-->6)-beta-D-glucopyranosyl]-ceramide (1), 1-O-[8-O-sulfo-(N-acetyl-alpha-D-neuraminosyl)-(2-->6)-beta-D-glucopyranosyll-ceramide (2) and 1-O-[(N-glycolyl-alpha-D-neuraminosyl)-(2-->8)-(N-acetyl- and N-glycolyl-alpha-D-neuraminosyl)-(2-->6)-beta-D-glucopyranosyl]-ceramide (3). The ceramide moieties were composed of heterogeneous unsubstituted fatty acid, 2-hydroxy fatty acid and phytosphingosine units. Compounds 2 and 3 represent new ganglioside molecular species.

  6. Interfacial stabilization of the antitumoral drug Paclitaxel in monolayers of GM1 and GD1a gangliosides.

    PubMed

    Heredia, Valeria; Maggio, Bruno; Beltramo, Dante M; Dupuy, Fernando G

    2015-10-01

    Molecular interactions between the anti-cancer agent Paclitaxel (Ptx), and two gangliosides with different sialic acid content, GM1 and GD1a, were investigated using the Langmuir film balance technique. Ptx showed interfacial activity reducing the air/water surface tension by 18 mN·m(-1). However, the drug was able to insert into preformed ganglioside monolayers at much higher surface pressures, indicating a preferential interaction of Ptx with GM1 and GD1a. Compression isotherms of binary mixtures of Ptx and GM1 or GD1a also indicated non-ideal mixed monolayers in which the drug became stabilized at the interface in the presence of gangliosides. Ptx reached much higher surface pressure values in the mixed monolayers than those sustained in pure Ptx, although partial desorption of the drug from the interface into the subphase was also observed at high Ptx contents. The mean molecular area of the mixtures showed condensation, mainly in the case of GD1a, whereas Ptx induced a decrease in the compressibility of monolayers when mixed with either GM1 or GD1a. Additionally, Brewster angle microscopy analysis indicated that higher amounts of Ptx are present at the mixed ganglioside/Ptx interface when compared to pure drug monolayers. Finally, GD1a micelles increased in size in the presence of Ptx, whereas GM1 micelles kept their diameter, according to dynamic light scattering measurements, which could be explained by the different properties of ganglioside monolayers. The results obtained on ganglioside-Ptx interactions allowed interpreting the different Ptx loading capacity of GM1 and GD1a, enabling them to act as potential drug carriers.

  7. Sialidase activities of cultured human fibroblasts and the metabolism of GM3 ganglioside

    SciTech Connect

    Usuki, S.; Lyu, S.C.; Sweeley, C.C.

    1988-05-15

    Free sialic acid has been found in the cell-conditioned medium of human foreskin fibroblasts. It is proposed that the accumulation of extracellular sialic acid may result from the hydrolysis of GM3 ganglioside on the cell surface of these fibroblasts. Sialidase activities with GM3 ganglioside and sialyllactitol as substrates were demonstrated in cell-conditioned medium, and the levels of their activities correlated positively with cell density. The GM3 sialidase activity at pH 4.5 was 4.1 and 38 pmol/h/ml of medium at sparse and confluent densities, respectively; the corresponding activities with sialyllactitol as the substrate were 12 and 75 pmol/h/ml of medium (pH 4.5). The pH versus activity profiles with GM3 as the substrate suggested the presence of a second sialidase with an optimal activity at pH 6.5 in the conditioned medium of preconfluent cells. This activity was virtually absent in the medium of contact-inhibited cells and could not be assayed with sialyllactitol as the substrate. The turnover of cell surface GM3 was assessed by pulse labeling human foreskin fibroblasts with a radioactive precursor of sialic acid ((1-14C)N-acetylmannosamine) and a radioactive precursor of ceramide ((3,3-3H2)serine). During a chase period of 24 h turnover of the doubly labeled cellular GM3 was observed; there was a loss of about 35% of the 14C-labeled sialic acid without any measureable loss of 3H-labeled ceramide from GM3. We have speculated that the enzyme-catalyzed removal of sialic acid from the GM3 ganglioside on the extracellular aspect of the plasma membrane may be a necessary event involved in the modulation of cell growth.

  8. Myelin-associated glycoprotein (MAG) protects neurons from acute toxicity using a ganglioside-dependent mechanism.

    PubMed

    Mehta, Niraj R; Nguyen, Thien; Bullen, John W; Griffin, John W; Schnaar, Ronald L

    2010-03-17

    Myelin-associated glycoprotein (MAG), a protein expressed on the innermost wrap of myelin, contributes to long-term axon stability as evidenced by progressive axon degeneration in Mag-null mice. Recently, MAG was also found to protect axons from acute toxic insults. In the current study, rat dorsal root ganglion neurons were cultured on control substrata and substrata adsorbed with myelin proteins. Neurons on myelin-adsorbed surfaces were resistant to acute degeneration of neurites induced by vincristine, a cancer chemotherapeutic agent with neuropathic side effects. Myelin-mediated protection was reversed by anti-MAG antibody and was absent when cells were cultured on extracts from Mag-null mouse myelin, confirming the protective role of MAG. Gangliosides (sialylated glycosphingolipids) are one functional class of axonal receptors for MAG. In the current studies, a direct role for gangliosides in mediating the acute protective effects of MAG was established. Treatment of neurons with sialidase, an enzyme that cleaves the terminal sialic acids required for MAG binding, reversed MAG's protective effect, as did treatment with (1R,2R)-1-phenyl-2-hexadecanoylamino-3-pyrrolidino-1-propanol, an inhibitor of glycosphingolipid biosynthesis. In contrast, treatment with phosphatidylinositol-specific phospholipase C, an enzyme that cleaves Nogo receptors (NgR, another class of MAG receptor), or with a peptide inhibitor of an NgR-associated signaling molecule p75(NTR), failed to diminish MAG-mediated protection. Inhibiting the Rho-associated protein kinase ROCK reversed protection. We conclude that MAG protects neurites from acute toxic insult via a ganglioside-mediated signaling pathway that involves activation of RhoA. Understanding MAG-mediated protection may provide opportunities to reduce axonal damage and loss.

  9. Suitability of the rare-earth compounds Dy2Ti2O7 and Gd3Al5O12 for low temperature (4K-20K) magnetic refrigeration cycle

    NASA Technical Reports Server (NTRS)

    Flood, D. J.

    1973-01-01

    Measurements were made of the magnetic entropy and magnetization of powered samples of the compounds Dy2Ti2O7 and Gd3Al5O12. The magnetization was measured for temperatures at and below 4.2 K, in applied fields ranging to 7.0 tesla. Isothermal changes in magnetic entropy were measured for temperatures from 1.2 to 20 K, in applied fields up to 10 tesla. The results of the measurements are consistent with a doublet ground state for Dy2Ti2O7, and an eight-fold degenerate ground state for Gd3Al5O12. Absolute values of magnetic entropy have been obtained at the lower temperatures, permitting the isotherms to be properly located in the S-H plane with the use of adiabatic magnetization data. The iso-field lines in the S-T plane were determined. The results indicate that Dy2Ti2O7 can absorb a maximum of 71 + or - 4 joules/kg of heat at 4.2 K, while Gd3Al5O12 can absorb 233 + or - joules/kg at the same temperature. The large difference between the two is most likely a result of crystal field interactions in the dysoprosium compound. Both materials can be cycled adiabatically between 4.2 and 20 K.

  10. Fluorescent property of the Gd3+-doped terbium complexes and crystal structure of [Tb(TPTZ)(H2O)6]Cl3.3H2O.

    PubMed

    Zhao, Yan-Fang; Zhao, Yong-Liang; Bai, Feng; Wei, Xiao-yan; Zhou, Yong-sheng; Shan, Mei-na; Li, Huan-huan; Ma, Rui-jun; Fu, Xiao-tao; Du, Yan

    2010-05-01

    The complex of Tb(TPTZ)Cl(3).3H(2)O was synthesized by adding the ethyl alcohol solution of TbCl(3) (1 mmol) to the solution of 2,4,6-tris-(2-pyridyl)-s-triazine(TPTZ, 1 mmol) with constant stirring. The solution which had been filtered was kept at the room temperature for 4 weeks, and then a kind of transparent crystal was formed. Besides, nine kinds of solid complexes in the different molar proportion of terbium to gadolinium had been synthesized by adopting the similar method mentioned above. It was inferred from the elemental analysis and rare earth complexometry that the composition of these complexes is (Tb(x)Gd(y))(TPTZ)Cl(3).3H(2)O (x : y = 0.9 : 0.1, 0.8 : 0.2, 0.7 : 0.3, 0.6 : 0.4, 0.5 : 0.5, 0.4 : 0.6, 0.3 : 0.7, 0.2 : 0.8, 0.1 : 0.9). The absorption spectra and photoluminescence of the complexes were determined in dimethylsulfoxide (DMF), which showed that the excitation of the complexes is mostly ligand based. The triplet state energy level of TPTZ was measured, indicating that the lowest excitation state energy level of Tb(III) and the triplet state energy level of TPTZ match well each other. The fluorescent data indicated that the fluorescent emission intensity of Tb(3+) ions would be enhanced in the complexes after terbium was doped with Gd(3+) ion. When x : y was 0.5 : 0.5, the fluorescent emission intensity was the largest. The result obtained by testing the X-ray diffraction of the monocrystal revealed that the molecular formula of the mono-crystal complex is [Tb(TPTZ)(H(2)O)(6)]Cl(3).3H(2)O. The number of metal ion coordinates is nine, and the tridentate TPTZ and six water molecules are bonded with terbium respectively. Besides, it also revealed that the monocrystal belongs to the monoclinic system, and space group Cc with the following unit cell parameters is a = 1.4785 (3) nm, b = 1.0547 (2) nm, c = 1.7385 (4) nm, beta = 94.42 (3) degrees, V = 2.7028 (9) nm(3) and Z = 4.

  11. Deficiency of ganglioside GM1 correlates with Parkinson's disease in mice and humans.

    PubMed

    Wu, Gusheng; Lu, Zi-Hua; Kulkarni, Neil; Ledeen, Robert W

    2012-10-01

    Several studies have successfully employed GM1 ganglioside to treat animal models of Parkinson's disease (PD), suggesting involvement of this ganglioside in PD etiology. We recently demonstrated that genetically engineered mice (B4galnt1(-/-) ) devoid of GM1 acquire characteristic symptoms of this disorder, including motor impairment, depletion of striatal dopamine, selective loss of tyrosine hydroxylase-expressing neurons, and aggregation of α-synuclein. The present study demonstrates similar symptoms in heterozygous mice (HTs) that express only partial GM1 deficiency. Symptoms were alleviated by administration of L-dopa or LIGA-20, a membrane-permeable analog of GM1 that penetrates the blood-brain barrier and accesses intracellular compartments. Immunohistochemical analysis of paraffin sections from PD patients revealed significant GM1 deficiency in nigral dopaminergic neurons compared with age-matched controls. This was comparable to the GM1 deficiency of HT mice and suggests that GM1 deficiency may be a contributing factor to idiopathic PD. We propose that HT mice with partial GM1 deficiency constitute an especially useful model for PD, reflecting the actual pathophysiology of this disorder. The results point to membrane-permeable analogs of GM1 as holding promise as a form of GM1 replacement therapy.

  12. Detection of cholera toxin in seafood using a ganglioside-liposome immunoassay.

    PubMed

    Ahn, Soohyoun; Durst, Richard A

    2008-05-01

    Microbiological contamination of foods continues to be a major concern in public health. Biological toxins are one class of important contaminants that can cause various human diseases. Outbreaks related to contamination by biological toxins or toxin-producing microorganisms have made it extremely important to develop rapid (approximately 20 min), sensitive and cost-effective analytical methods. This paper describes the development of a sensitive bioassay for the detection of cholera toxin (CT) in selected seafood samples, using ganglioside-incorporated liposomes. In this study, the assays were run with food samples spiked with various concentrations of CT. The limit of detection (LOD) increased by a factor of about 10-20 in most food samples, compared with the LOD in the buffer system previously reported. However, the LOD of toxins in food samples (8 × 10-3 × 10(3) fg/mL for CT) was still comparable to, or lower than, that previously reported for other assays. The results from this study demonstrate that the bioassays using ganglioside-liposomes can detect the toxin directly in the field screening of food samples rapidly, simply and reliably, without the need for complex instrumentation.

  13. Ganglioside inhibition of glutamate-mediated protein kinase C translocation in primary cultures of cerebellar neurons

    SciTech Connect

    Vaccarino, F.; Guidotti, A.; Costa, E.

    1987-12-01

    In primary cultures of cerebellar granule cells, protein kinase C (PKC) translocation and activation can be triggered by the stimulation of excitatory amino acid neurotransmitter receptors. Glutamate evokes a dose-related translocation of 4-..beta..-(/sup 3/H)phorbol 12,13-dibutyrate /(/sup 3/H)-P(BtO)/sub 2// binding sites from the cytosol to the neuronal membrane and stimulates the incorporation of /sup 32/P into a number of membrane proteins, particularly protein bands in the range of 80, 50, and 40 kDa. The glutamate-evoked PKC translocation is Mg/sup 2 +/ sensitive, is prevented by 2-amino-5-phosphonovalerate and phencyclidine, is not inhibited by nitrendipine (a voltage-dependent Ca/sup 2 +/-channel-blocker) but is abolished by the removal of Ca/sup 2 +/ from the incubation medium, suggesting that glutamate-mediated Ca/sup 2 +/ influx is operative in the redistribution of PKC. Exposure of granule cells to the gangliosides trisialosylgangliotetraglycosylceramide (GT1b) of monosialosylgangliotetraglycosylceramide (GM1) inhibits the translocation and activation of PKC evoked by glutamate. These glycosphingolipids fail to interfere with glutamate binding to its high-affinity recognition site of with the (/sup 3/H)P(BtO)/sub 2/ binding, nor do they affect the Ca/sup 2 +/ influx. These gangliosides may prevent PKC translocation by interfering with the PKC binding to the neuronal membrane phosphatidylserine.

  14. Assessment of ganglioside age-related and topographic specificity in human brain by Orbitrap mass spectrometry.

    PubMed

    Sarbu, Mirela; Dehelean, Liana; Munteanu, Cristian V A; Vukelić, Željka; Zamfir, Alina D

    2017-03-15

    The gangliosides (GGs) of the central nervous system (CNS) exhibit age and topographic specificity and these patterns may correlate with the functions and pathologies of the brain regions. Here, chloroform extraction, nanoelectrospray (nanoESI) negative ionization, together with Orbitrap high resolution mass spectrometry (MS) determined the topographic and age-related GG specificity in normal adult human brain. Mapping of GG mixtures extracted from 20 to 82 year old frontal and occipital lobes revealed besides a decrease in the GG number with age, a variability of sialylation degree within the brain regions. From the 111 species identified, 105 were distinguished in the FL20, 74 in OL20, 46 in FL82 and 56 in OL82. The results emphasize that within the juvenile brain, GG species exhibit a higher expression in the FL than in OL, while in the aged brain the number of GG species is higher in the OL. By applying MS/MS analysis, the generated fragment ions confirmed the incidence of GT1c (d18:1/18:0) and GT1c (d18:1/20:0) in the investigated samples. The present findings are of major value for further clinical studies carried out using Orbitrap MS in order to correlate gangliosides with CNS disorders.

  15. Identification of a Unique Ganglioside Binding Loop within Botulinum Neurotoxins C and D-SA

    SciTech Connect

    Karalewitz, Andrew P.-A.; Kroken, Abby R.; Fu, Zhuji; Baldwin, Michael R.; Kim, Jung-Ja P.; Barbieri, Joseph T.

    2010-09-22

    The botulinum neurotoxins (BoNTs) are the most potent protein toxins for humans. There are seven serotypes of BoNTs (A-G) based on a lack of cross antiserum neutralization. BoNTs utilize gangliosides as components of the host receptors for binding and entry into neurons. Members of BoNT/C and BoNT/D serotypes include mosaic toxins that are organized in D/C and C/D toxins. One D/C mosaic toxin, BoNT/D-South Africa (BoNT/D-SA), was not fully neutralized by immunization with BoNT serotype C or D, which stimulated this study. Here the crystal structures of the receptor binding domains of BoNT/C, BoNT/D, and BoNT/D-SA are presented. Biochemical and cell binding studies show that BoNT/C and BoNT/D-SA possess unique mechanisms for ganglioside binding. These studies provide new information about how the BoNTs can enter host cells as well as a basis for understanding the immunological diversity of these neurotoxins.

  16. Syngeneic anti-idiotypic monoclonal antibodies to an anti-NeuGc-containing ganglioside monoclonal antibody.

    PubMed

    Vázquez, A M; Pérez, A; Hernández, A M; Macías, A; Alfonso, M; Bombino, G; Pérez, R

    1998-12-01

    An IgM monoclonal antibody (MAb), named P3, has the characteristic to react specifically with a broad battery of N-glycolyl containing-gangliosides and with antigens expressed on breast tumors. When this MAb was administered alone in syngeneic mice, an specific IgG anti-idiotypic antibody (Ab2) response was induced, this Ab2 response was increased when P3 MAb was injected coupled to a carrier protein and in the presence of Freund's adjuvant. Spleen cells from these mice were used in somatic-cell hybridization experiments, using the murine myeloma cell line P3-X63-Ag8.653 as fusion partner. Five Ab2 MAbs specific to P3 MAb were selected. These IgG1 Ab2 MAbs were able to block the binding of P3 MAb to GM3(NeuGc) ganglioside and to a human breast carcinoma cell line. Cross-blocking experiments demonstrated that these Ab2 MAbs are recognizing the same or very close sites on the Abl MAb. The five Ab2 MAbs were injected into syngeneic mice and four of them produced strong anti-anti-idiotypic antibody (Ab3) response. While these Ab2 MAbs were unable to generate Ab3 antibodies with the same antigenic specificity than P3 MAb, three of them induced antibodies bearing P3 MAb idiotopes (Ag-Id+ Ab3). These results demonstrated that these Ab2 MAbs are not "internal image" antibodies, but they could define "regulatory idiotopes."

  17. GM1 and GD1a gangliosides modulate toxic and inflammatory effects of E. coli lipopolysaccharide by preventing TLR4 translocation into lipid rafts.

    PubMed

    Nikolaeva, Svetlana; Bayunova, Lubov; Sokolova, Tatyana; Vlasova, Yulia; Bachteeva, Vera; Avrova, Natalia; Parnova, Rimma

    2015-03-01

    Exogenous gangliosides are known to inhibit the effects of Escherichia coli lipopolysaccharide (LPS) in different cells exhibiting anti-inflammatory and immunosuppressive activities. The mechanisms underlying ganglioside action are not fully understood. Because LPS recognition and receptor complex formation occur in lipid rafts, and gangliosides play a key role in their maintenance, we hypothesize that protective effects of exogenous gangliosides would depend on inhibition of LPS signaling via prevention of TLR4 translocation into lipid rafts. The effect of GM1 and GD1a gangliosides on LPS-induced toxic and inflammatory reactions in PC12 cells, and in epithelial cells isolated from the frog urinary bladder, was studied. In PC12 cells, GD1a and GM1 significantly reduced the effect of LPS on the decrease of cell survival and on stimulation of reactive oxygen species production. In epithelial cells, gangliosides decreased LPS-stimulated iNOS expression, NO, and PGE2 production. Subcellular fractionation, in combination with immunoblotting, showed that pretreatment of cells with GM1, GD1a, or methyl-β-cyclodextrin, completely eliminated the effect of LPS on translocation of TLR4 into lipid rafts. The results are consistent with the hypothesis that ganglioside-induced prevention of TLR4 translocation into lipid rafts could be a mechanism of protection against LPS in various cells.

  18. Neuraminidase-1 contributes significantly to the degradation of neuronal B-series gangliosides but not to the bypass of the catabolic block in Tay-Sachs mouse models.

    PubMed

    Timur, Z K; Akyildiz Demir, S; Marsching, C; Sandhoff, R; Seyrantepe, V

    2015-09-01

    Tay–Sachs disease is a severe lysosomal storage disorder caused by mutations in the HEXA gene coding for α subunit of lysosomal β-Hexosaminidase A enzyme, which converts GM2 to GM3 ganglioside. HexA(−/−) mice, depleted of the β-Hexosaminidase A iso-enzyme, remain asymptomatic up to 1 year of age because of a metabolic bypass by neuraminidase(s). These enzymes remove a sialic acid residue converting GM2 to GA2, which is further degraded by the still intact β-Hexosaminidase B iso-enzyme into lactosylceramide. A previously identified ganglioside metabolizing neuraminidase, Neu4, is abundantly expressed in the mouse brain and has activity against gangliosides like GM2in vitro. Neu4(−/−) mice showed increased GD1a and decreased GM1 ganglioside in the brain suggesting the importance of the Neu4 in ganglioside catabolism. Mice with targeted disruption of both HexA and Neu4 genes showed accumulating GM2 ganglioside and epileptic seizures with 40% penetrance, indicating that the neuraminidase Neu4 is a modulatory gene, but may not be the only neuraminidase contributing to the metabolic bypass in HexA(−/−) mice. Therefore, we elucidated the biological role of neuraminidase-1 in ganglioside degradation in mouse. Analysis of HexA(−/−) Neu1(−/−) and HexA(−/−) Neu4(−/−) Neu1(−/−) mice models showed significant contribution of neuraminidase-1 on B-series ganglioside degradation in the brain. Therefore, we speculate that other neuraminidase/neuraminidases such as Neu2 and/or Neu3 might be also involved in the ganglioside degradation pathway in HexA(−/−) mice.

  19. Alterations in cholesterol and ganglioside GM1 content of lipid rafts in platelets from patients with Alzheimer disease.

    PubMed

    Liu, Li; Zhang, Ke; Tan, Liang; Chen, Yu-Hua; Cao, Yun-Peng

    2015-01-01

    The aim of this study was to investigate the changes in the protein, cholesterol, and ganglioside GM1 content of lipid rafts in platelets from patients with Alzheimer disease (AD), and identify potential blood biomarkers of the disease. A total of 31 Chinese patients with AD and 31 aged-matched control subjects were selected. Lipid rafts were isolated from platelets using Optiprep gradient centrifugation. The protein content of lipid rafts was evaluated using Micro BCA assay, the cholesterol content using molecular probes, ganglioside GM1 content using colorimetry and dot-blotting analysis. The results showed that the cholesterol and ganglioside GM1 content of lipid rafts from platelets was significantly higher in patients with AD than aged-matched control subjects, whereas the protein content of lipid rafts did not show any differences between the 2 groups. These results indicate that the increases in the cholesterol and ganglioside GM1 content of lipid rafts from the platelets of patients with AD might serve as a biochemical adjunct to the clinical diagnosis of AD.

  20. Neu3 sialidase-mediated ganglioside conversion is necessary for axon regeneration and is blocked in CNS axons.

    PubMed

    Kappagantula, Sunil; Andrews, Melissa R; Cheah, Menghon; Abad-Rodriguez, José; Dotti, Carlos G; Fawcett, James W

    2014-02-12

    PNS axons have a high intrinsic regenerative ability, whereas most CNS axons show little regenerative response. We show that activation of Neu3 sialidase, also known as Neuraminidase-3, causing conversion of GD1a and GT1b to GM1 ganglioside, is an essential step in regeneration occurring in PNS (sensory) but not CNS (retinal) axons in adult rat. In PNS axons, axotomy activates Neu3 sialidase, increasing the ratio of GM1/GD1a and GM1/GT1b gangliosides immediately after injury in vitro and in vivo. No change in the GM1/GD1a ratio after axotomy was observed in retinal axons (in vitro and in vivo), despite the presence of Neu3 sialidase. Externally applied sialidase converted GD1a ganglioside to GM1 and rescued axon regeneration in CNS axons and in PNS axons after Neu3 sialidase blockade. Neu3 sialidase activation in DRGs is initiated by an influx of extracellular calcium, activating P38MAPK and then Neu3 sialidase. Ganglioside conversion by Neu3 sialidase further activates the ERK pathway. In CNS axons, P38MAPK and Neu3 sialidase were not activated by axotomy.

  1. GM2-ganglioside metabolism in hexosaminidase A deficiency states: determination in situ using labeled GM2 added to fibroblast cultures.

    PubMed Central

    Raghavan, S S; Krusell, A; Krusell, J; Lyerla, T A; Kolodny, E H

    1985-01-01

    To clarify the relationship between hexosaminidase A (HEX A) activity and GM2-ganglioside hydrolysis in atypical clinical situations of HEX A deficiency, we have developed a simple method to assess GM2-ganglioside metabolism in cultured fibroblasts utilizing GM2 labeled with tritium in the sphingosine portion of the molecule. The radioactive lipid is added to the media of cultured skin fibroblasts, and after 10 days the cells are thoroughly washed, then harvested, and their lipid composition analyzed by HPLC. The degree of hydrolysis of the ingested GM2 is determined by comparing the amount of radioactive counts recovered in undegraded substrate with total cellular radioactivity. A deficiency in GM2-ganglioside hydrolysis was demonstrated in seven HEX A-deficient adults with neurological signs and in two healthy-appearing adolescents with older affected siblings. In each case, an analysis of endogenous monosialoganglioside composition revealed an increase in GM2-ganglioside, confirming the presence of a block in the metabolism of GM2. No defect in GM2-catabolism was found in four other healthy individuals with HEX A deficiency. This method of assay is especially helpful in the evaluation of atypical cases of HEX A deficiency for the definitive diagnosis of GM2-gangliosidosis. Images Fig. 1 PMID:2934978

  2. [IR/UV spectroscopic analysis of gangliosides and their microstructures of polymeric aggregates observed by AFM technique].

    PubMed

    Wang, Hai-long; Sun, Run-guang; Zhang, Jing; Hao, Chang-chun

    2009-04-01

    Gangliosides, a kind of acid glycosphingolipid containing sialic acid, plays a very important physiological role in biomembrane as one of the important components of neurocyte membrane. They were extracted from bovine brain by the Folch method and purified by silica gel and DEAE-Sephadex A-25 column chromatograph. Their molecular functional groups and microstructures of polymeric aggregates were studied by infrared spectrum (IR), ultraviolet spectrum (UV) and atomic force microscope (AFM). The experimental results indicate that: 55.2 mg of Gls from 100 g of wet bovine brain had a certain purity, 62.84%. And their UV absorption spectra appeared at 195 nm, near to the results reported by other peoples. Compared with the IR spectra of sialic acid, the experimental results showed that the structures of the products had the units of sialic acid. In order to investigate the aggregate structures of ganglioside. AFM technique was applied in water, and the results showed that gangliosides can form spherical or ellipsoidal structures in water. It was determined that the size of polymeric aggregates of gangliosides varies between 55 and 380 nm, the average size is (148.9+/-66.7) nm; the height is between 1.0 and 5.0 nm, and the average height is (3.25+/-1.01) nm. The experimental results provide a theoretical and experimental basis for investigating biological activity and the exploitation and utilization of neural drugs.

  3. Frequent co-expression of EGFR and NeuGcGM3 ganglioside in cancer: it's potential therapeutic implications.

    PubMed

    Palomo, Addys González; Santana, Rancés Blanco; Pérez, Xiomara Escobar; Santana, Damián Blanco; Gabri, Mariano Rolando; Monzon, Kalet León; Pérez, Adriana Carr

    2016-10-01

    Interaction between epidermal growth factor receptor (EGFR) signaling with GM3 ganglioside expression has been previously described. However, little is known about EGFR and NeuGcGM3 co-expression in cancer patients and their therapeutic implications. In this paper, we evaluate the co-expression of EGFR and NeuGcGM3 ganglioside in tumors from 92 patients and in two spontaneous lung metastasis models of mice (Lewis lung carcinoma (3LL-D122) in C57BL/6 and mammary carcinoma (4T1) in BALB/c). As results, co-expression of EGFR and NeuGcGM3 ganglioside was frequently observed in 63 of 92 patients (68 %), independently of histological subtype. Moreover, EGFR is co-expressed with NeuGcGM3 ganglioside in the metastasis of 3LL-D122 and 4T1 murine models. Such dual expression appears to be therapeutically relevant, since combined therapy with mAbs against these two molecules synergistically increase the survival of mice treated. Overall, our results suggest that NeuGcGM3 and EGFR may coordinately contribute to the tumor cell biology and that therapeutic combinations against these two targets might be a valid strategy to explore.

  4. Gangliosides and Nogo receptors independently mediate myelin-associated glycoprotein inhibition of neurite outgrowth in different nerve cells.

    PubMed

    Mehta, Niraj R; Lopez, Pablo H H; Vyas, Alka A; Schnaar, Ronald L

    2007-09-21

    In the injured nervous system, myelin-associated glycoprotein (MAG) on residual myelin binds to receptors on axons, inhibits axon outgrowth, and limits functional recovery. Conflicting reports identify gangliosides (GD1a and GT1b) and glycosylphosphatidylinositol-anchored Nogo receptors (NgRs) as exclusive axonal receptors for MAG. We used enzymes and pharmacological agents to distinguish the relative roles of gangliosides and NgRs in MAG-mediated inhibition of neurite outgrowth from three nerve cell types, dorsal root ganglion neurons (DRGNs), cerebellar granule neurons (CGNs), and hippocampal neurons. Primary rat neurons were cultured on control substrata and substrata adsorbed with full-length native MAG extracted from purified myelin. The receptors responsible for MAG inhibition of neurite outgrowth varied with nerve cell type. In DRGNs, most of the MAG inhibition was via NgRs, evidenced by reversal of inhibition by phosphatidylinositol-specific phospholipase C (PI-PLC), which cleaves glycosylphosphatidylinositol anchors, or by NEP1-40, a peptide inhibitor of NgR. A smaller percentage of MAG inhibition of DRGN outgrowth was via gangliosides, evidenced by partial reversal by addition of sialidase to cleave GD1a and GT1b or by P4, an inhibitor of ganglioside biosynthesis. Combining either PI-PLC and sialidase or NEP1-40 and P4 was additive. In contrast to DRGNs, in CGNs MAG inhibition was exclusively via gangliosides, whereas inhibition of hippocampal neuron outgrowth was mostly reversed by sialidase or P4 and only modestly reversed by PI-PLC or NEP1-40 in a non-additive fashion. A soluble proteolytic fragment of native MAG, dMAG, also inhibited neurite outgrowth. In DRGNs, dMAG inhibition was exclusively NgR-dependent, whereas in CGNs it was exclusively ganglioside-dependent. An inhibitor of Rho kinase reversed MAG-mediated inhibition in all nerve cells, whereas a peptide inhibitor of the transducer p75(NTR) had cell-specific effects quantitatively similar to Ng

  5. Deciphering the glycolipid code of Alzheimer's and Parkinson's amyloid proteins allowed the creation of a universal ganglioside-binding peptide.

    PubMed

    Yahi, Nouara; Fantini, Jacques

    2014-01-01

    A broad range of microbial and amyloid proteins interact with cell surface glycolipids which behave as infectivity and/or toxicity cofactors in human pathologies. Here we have deciphered the biochemical code that determines the glycolipid-binding specificity of two major amyloid proteins, Alzheimer's β-amyloid peptide (Aβ) and Parkinson's disease associated protein α-synuclein. We showed that both proteins interact with selected glycolipids through a common loop-shaped motif exhibiting little sequence homology. This 12-residue domain corresponded to fragments 34-45 of α-synuclein and 5-16 of Aβ. By modulating the amino acid sequence of α-synuclein at only two positions in which we introduced a pair of histidine residues found in Aβ, we created a chimeric α-synuclein/Aβ peptide with extended ganglioside-binding properties. This chimeric peptide retained the property of α-synuclein to recognize GM3, and acquired the capacity to recognize GM1 (an Aβ-inherited characteristic). Free histidine (but not tryptophan or asparagine) and Zn2+ (but not Na+) prevented this interaction, confirming the key role of His-13 and His-14 in ganglioside binding. Molecular dynamics studies suggested that the chimeric peptide recognized cholesterol-constrained conformers of GM1, including typical chalice-shaped dimers, that are representative of the condensed cholesterol-ganglioside complexes found in lipid raft domains of the plasma membrane of neural cells. Correspondingly, the peptide had a particular affinity for raft-like membranes containing both GM1 and cholesterol. The chimeric peptide also interacted with several other gangliosides, including major brain gangliosides (GM4, GD1a, GD1b, and GT1b) but not with neutral glycolipids such as GlcCer, LacCer or asialo-GM1. It could inhibit the binding of Aβ1-42 onto neural SH-SY5Y cells and did not induce toxicity in these cells. In conclusion, deciphering the glycolipid code of amyloid proteins allowed us to create a universal

  6. Structural and Enzymatic Characterization of NanS (YjhS) a 9-O-Acetyl N-acetylneuraminic Acid Esterase from Escherichia coli O157:H7

    SciTech Connect

    E Rangarajan; K Ruane; A Proteau; J Schrag; R Valladares; C Gonzalez; M Gilbert; A Yakunin; M Cygler

    2011-12-31

    There is a high prevalence of sialic acid in a number of different organisms, resulting in there being a myriad of different enzymes that can exploit it as a fermentable carbon source. One such enzyme is NanS, a carbohydrate esterase that we show here deacetylates the 9 position of 9-O-sialic acid so that it can be readily transported into the cell for catabolism. Through structural studies, we show that NanS adopts a SGNH hydrolase fold. Although the backbone of the structure is similar to previously characterized family members, sequence comparisons indicate that this family can be further subdivided into two subfamilies with somewhat different fingerprints. NanS is the founding member of group II. Its catalytic center contains Ser19 and His301 but no Asp/Glu is present to form the classical catalytic triad. The contribution of Ser19 and His301 to catalysis was confirmed by mutagenesis. In addition to structural characterization, we have mapped the specificity of NanS using a battery of substrates.

  7. Lyso-GM2 ganglioside: a possible biomarker of Tay-Sachs disease and Sandhoff disease.

    PubMed

    Kodama, Takashi; Togawa, Tadayasu; Tsukimura, Takahiro; Kawashima, Ikuo; Matsuoka, Kazuhiko; Kitakaze, Keisuke; Tsuji, Daisuke; Itoh, Kohji; Ishida, Yo-Ichi; Suzuki, Minoru; Suzuki, Toshihiro; Sakuraba, Hitoshi

    2011-01-01

    To find a new biomarker of Tay-Sachs disease and Sandhoff disease. The lyso-GM2 ganglioside (lyso-GM2) levels in the brain and plasma in Sandhoff mice were measured by means of high performance liquid chromatography and the effect of a modified hexosaminidase (Hex) B exhibiting Hex A-like activity was examined. Then, the lyso-GM2 concentrations in human plasma samples were determined. The lyso-GM2 levels in the brain and plasma in Sandhoff mice were apparently increased compared with those in wild-type mice, and they decreased on intracerebroventricular administration of the modified Hex B. The lyso-GM2 levels in plasma of patients with Tay-Sachs disease and Sandhoff disease were increased, and the increase in lyso-GM2 was associated with a decrease in Hex A activity. Lyso-GM2 is expected to be a potential biomarker of Tay-Sachs disease and Sandhoff disease.

  8. Picomolar inhibition of cholera toxin by a pentavalent ganglioside GM1os-calix[5]arene.

    PubMed

    Garcia-Hartjes, Jaime; Bernardi, Silvia; Weijers, Carel A G M; Wennekes, Tom; Gilbert, Michel; Sansone, Francesco; Casnati, Alessandro; Zuilhof, Han

    2013-07-14

    Cholera toxin (CT), the causative agent of cholera, displays a pentavalent binding domain that targets the oligosaccharide of ganglioside GM1 (GM1os) on the periphery of human abdominal epithelial cells. Here, we report the first GM1os-based CT inhibitor that matches the valency of the CT binding domain (CTB). This pentavalent inhibitor contains five GM1os moieties linked to a calix[5]arene scaffold. When evaluated by an inhibition assay, it achieved a picomolar inhibition potency (IC50 = 450 pM) for CTB. This represents a significant multivalency effect, with a relative inhibitory potency of 100,000 compared to a monovalent GM1os derivative, making GM1os-calix[5]arene one of the most potent known CTB inhibitors.

  9. Nanomechanical detection of cholera toxin using microcantilevers functionalized with ganglioside nanodiscs

    NASA Astrophysics Data System (ADS)

    Tark, Soo-Hyun; Das, Aditi; Sligar, Stephen; Dravid, Vinayak P.

    2010-10-01

    The label-free detection of cholera toxin is demonstrated using microcantilevers functionalized with ganglioside nanodiscs. The cholera toxin molecules bind specifically to the active membrane protein encased in nanodiscs, nanoscale lipid bilayers surrounded by an amphipathic protein belt, immobilized on the cantilever surface. The specific molecular binding results in cantilever deflection via the formation of a surface stress-induced bending moment. The nanomechanical cantilever response is quantitatively monitored by optical interference. The consistent and reproducible nanomechanical detection of cholera toxin in nanomolar range concentrations is demonstrated. The results validated with such a model system suggest that the combination of a microcantilever platform with receptor nanodiscs is a promising approach for monitoring invasive pathogens and other types of biomolecular detection relevant to drug discovery.

  10. From the ganglioside GQ1balpha to glycomimetic antagonists of the myelin-associated glycoprotein (MAG).

    PubMed

    Ernst, Beat; Schwardt, Oliver; Mesch, Stefanie; Wittwer, Matthias; Rossato, Gianluca; Vedani, Angelo

    2010-01-01

    The tetrasaccharide 4, a substructure of ganglioside GQ1balpha, shows a remarkable affinity for the myelin-associated glycoprotein (MAG) and was therefore selected as starting point for a lead optimization program. In our search for structurally simplified and pharmacokinetically improved mimics of 4, antagonists with modifications of the core disaccharide Galbeta(1-3)GalNAc, as well as the terminal alpha(2-3)- and the internal alpha(2-6)-linked neuraminic acid were synthesized and tested in target-based binding assays. Compared to the reference tetrasaccharide 4, the most potent antagonist 17 exhibits a 360-fold improved affinity. Furthermore, pharmacokinetic parameters such as stability in the cerebrospinal fluid, logD and permeation through the BBB indicate the drug-like properties of antagonist 17.

  11. Positive regulation of myoblast differentiation by medaka Neu3b sialidase through gangliosides desialylation.

    PubMed

    Shiozaki, Kazuhiro; Harasaki, Yusuke; Fukuda, Midori; Yoshinaga, Ayana; Ryuzono, Sena; Chigwechokha, Petros Kingstone; Komatsu, Masaharu; Miyagi, Taeko

    2016-04-01

    Sialidase Neu3b is an unique enzyme conserved in medaka and tilapia, but not in mammals. Previous study revealed that medaka Neu3b is localized at cytosol and is a ganglioside-specific sialidase. Neu3b functions, however, have not been understood, while Neu3a sialidase, which is widely conserved from human to fish, is known as a regulator of neurite formation. Here, we investigated the biological function of Neu3b for C2C12 myoblast cell differentiation. Bioinformatics analysis using genome browser revealed the presence of neu3b gene in some orders of fish species such as Beloniformes, Perciformes and Cyprinodontiformes. With the treatment of 2% horse serum, Neu3b-overexpression accelerated myoblast cell differentiation to myotubes accompanied with up-regulation of myogenesis biomarkers mRNA, myod and myog. Neu3b altered ganglioside composition in C2C12 cells results showing a decrease in GM2, and the increase of Lac-Cer, while desialylation of glycoproteins were not detected. Contrary to cell differentiation, Neu3b cell proliferation was suppressed in normal growth medium. To understand the mechanism of the alteration of cell differentiation and proliferation, phosphorylation of signal molecules in EGFR/ERK pathway was investigated. Neu3b induced a decline in phosphorylation of ERK and EGFR. Surprisingly, immuno-blot and real-time PCR analysis revealed that down-regulation of egfr gene could be involved in the acceleration of cell differentiation by Neu3b. These results suggested that Neu3b sialidase is a positive regulator for myoblast differentiation, similar with mammalian cytosolic sialidase Neu2.

  12. Effects of neonatal ganglioside GM1 administration on memory in adult and old rats.

    PubMed

    Silv, R H; Bergamo, M; Frussa-Filho, R

    2000-09-01

    Numerous investigations have been reporting the involvement of GM1 ganglioside in central nervous system development and memory formation. The effects of neonatal treatment with GMI ganglioside on the performance of adult rats in a plus-maze discriminative avoidance task and old rats in a step-down passive avoidance task were investigated. Rats were injected subcutaneously from day 3 to 15 after birth with 10 mg/kg GM1 or saline. GM1 treatment did not modify indicative landmarks of physical and motor development. Behavioural tasks were carried out when the animals were 4 (discriminative avoidance) or 24 (passive avoidance) months old. Discriminative avoidance conditioning was performed in a modified elevated plus-maze. During the training session, the animals received aversive stimulation (light and hot air blow) in one of the enclosed arms. Tests were performed 7, 14 and 21 days after conditioning (tests 1, 2 and 3), in the absence of the aversive stimulation. In all tests, GM1-treated animals spent less time in the aversive arm than in the non-aversive enclosed arm. Control animals, however, spent a shorter time in the aversive arm only in tests 1 and 2. Passive avoidance conditioning was performed in an acrylic box with a grid floor, that was partially covered by an inclined platform. Animals were placed on the platform and received a 0,5 mA foot shock when stepped down. A test was performed 48 hr later. Latency to step down presented by GM 1-treated animals was significantly higher in the test session, whereas no significant increase in latency to step down was found for control animals. The results suggest a possible action of GM1 on the maturation of the central nervous system that persists during adulthood and ageing.

  13. Guillain–Barré syndrome and anti-ganglioside antibodies: a clinician-scientist’s journey

    PubMed Central

    YUKI, Nobuhiro

    2012-01-01

    Guillain–Barré syndrome (GBS) is the most frequent cause of acute flaccid paralysis. Having seen my first GBS patient in 1989, I have since then dedicated my time in research towards understanding the pathogenesis of GBS. Along with several colleagues, we identified IgG autoantibodies against ganglioside GM1 in two patients with GBS subsequent to Campylobacter jejuni enteritis. We proceeded to demonstrate molecular mimicry between GM1 and bacterial lipo-oligosaccharide of C. jejuni isolated from a patient with GBS. Our group then established a disease model for GBS by sensitization with GM1 or GM1-like lipo-oligosaccharide. With this, a new paradigm that carbohydrate mimicry can cause autoimmune disorders was demonstrated, making GBS the first proof of molecular mimicry in autoimmune disease. Patients with Fisher syndrome, characterized by ophthalmoplegia and ataxia, can develop the disease after an infection by C. jejuni. We showed that the genetic polymorphism of C. jejuni sialyltransferase, an enzyme essential to the biosynthesis of ganglioside-like lipo-oligosaccharides determines whether patients develop GBS or Fisher syndrome. This introduces another paradigm that microbial genetic polymorphism can determine the clinical phenotype of human autoimmune diseases. Similarities between the clinical presentation of Fisher syndrome and Bickerstaff brainstem encephalitis have caused debate as to whether they are in fact the same disease. We demonstrated that IgG anti-GQ1b antibodies were common to both, suggesting that they are part of the same disease spectrum. We followed this work by clarifying the nosological relationship between the various clinical presentations within the anti-GQ1b antibody syndrome. In this review, I wanted to share my journey from being a clinician to a clinician-scientist in the hopes of inspiring younger clinicians to follow a similar path. PMID:22850724

  14. Analysis of humoral immune responses to LM1 ganglioside in guinea pigs.

    PubMed

    Gu, Yajuan; Chen, Zi-Wei; Siegel, Allan; Koshy, Ranie; Ramirez, Cristhian; Raabe, Timothy D; Devries, George H; Ilyas, Amjad A

    2012-05-15

    Guillain-Barré syndrome (GBS) is an autoimmune-mediated disease triggered by a preceding infection. A substantial body of evidence implicates antibodies to various gangliosides in subtypes of GBS. A significant proportion of patients with acute demyelinating subset of GBS have IgG antibodies against peripheral nervous system myelin specific neolactogangliosides such as LM1 and Hex-LM1. Although anti-neolactoganglioside antibodies in GBS were described more than two decades ago, their pathogenic role in neuropathy remains unknown due to the lack of suitable experimental models. In this study, we immunized ten guinea pigs with purified LM1 ganglioside mixed with keyhole limpet hemocyanin (KLH) and emulsified in complete Freund's adjuvant (CFA). Control guinea pigs were injected with KLH emulsified in CFA only. The animals were bled every four week intervals. The animals were boosted 3 times every four weeks. Experiments were terminated four months after initial immunization. Nine of 10 guinea pigs immunized with LM1 exhibited antibody responses to LM1. Anti-LM1 IgG titers in nine guinea pigs ranged from 1:400 to 1:12,800 at 16-weeks after initial immunization. Anti-LM1 antibodies were predominantly of IgG2 subclass. One guinea pig with the highest levels of IgG antibodies exhibited mild signs of neuropathy. There was no evidence of demyelination or inflammation in the sciatic nerves of LM1-immunized guinea pigs. Anti-LM1 antibodies bound to rat sciatic nerve myelin and to isolated rat Schwann cells. In summary, our findings suggest that relatively high levels of anti-LM1 IgG antibodies can be induced in guinea pigs and that LM1 is localized in peripheral nerve myelin and in Schwann cells. Further studies are needed to determine the pathogenic potential of anti-neolactoganglioside antibodies in neuropathy.

  15. Synthesis and characterization of N-parinaroyl analogs of ganglioside GM3 and de-N-acetyl GM3. Interactions with the EGF receptor kinase

    NASA Technical Reports Server (NTRS)

    Song, W.; Welti, R.; Hafner-Strauss, S.; Rintoul, D. A.; Spooner, B. S. (Principal Investigator)

    1993-01-01

    A specific plasma membrane glycosphingolipid, known as ganglioside GM3, can regulate the intrinsic tyrosyl kinase activity of the epidermal growth factor (EGF) receptor; this modulation is not associated with alterations in hormone binding to the receptor. GM3 inhibits EGF receptor tyrosyl kinase activity in detergent micelles, in plasma membrane vesicles, and in whole cells. In addition, immunoaffinity-purified EGF receptor preparations contain ganglioside GM3 (Hanai et al. (1988) J. Biol. Chem. 263, 10915-10921), implying that the glycosphingolipid is intimately associated with the receptor kinase in cell membranes. Both the nature of this association and the molecular mechanism of kinase inhibition remain to be elucidated. In this report, we describe the synthesis of a fluorescent analog of ganglioside GM3, in which the native fatty acid was replaced with trans-parinaric acid. This glycosphingolipid inhibited the receptor kinase activity in a manner similar to that of the native ganglioside. A modified fluorescent glycosphingolipid, N-trans-parinaroyl de-N-acetyl ganglioside GM3, was also prepared. This analog, like the nonfluorescent de-N-acetyl ganglioside GM3, had no effect on receptor kinase activity. Results from tryptophan fluorescence quenching and steady-state anisotropy measurements in membranes containing these fluorescent probes and the human EGF receptor were consistent with the notion that GM3, but not de-N-acetyl GM3, interacts specifically with the receptor in intact membranes.

  16. DNA vaccine expressing the mimotope of GD2 ganglioside induces protective GD2 cross-reactive antibody responses.

    PubMed

    Bolesta, Elizabeth; Kowalczyk, Aleksandra; Wierzbicki, Andrzej; Rotkiewicz, Piotr; Bambach, Barbara; Tsao, Chun-Yen; Horwacik, Irena; Kolinski, Andrzej; Rokita, Hanna; Brecher, Martin; Wang, Xinhui; Ferrone, Soldano; Kozbor, Danuta

    2005-04-15

    The GD2 ganglioside expressed on neuroectodermally derived tumors, including neuroblastoma and melanoma, is weakly immunogenic in tumor-bearing patients and induces predominantly immunoglobulin (Ig)-M antibody responses in the immunized host. Here, we investigated whether interconversion of GD2 into a peptide mimetic form would induce GD2 cross-reactive IgG antibody responses in mice. Screening of the X(15) phage display peptide library with the anti-GD2 monoclonal antibody (mAb) 14G2a led to isolation of mimetic peptide 47, which inhibited the binding of 14G2a antibody to GD2-positive tumor cells. The peptide was also recognized by GD2-specific serum antibodies from a patient with neuroblastoma, suggesting that it bears an internal image of GD2 ganglioside expressed on the tumor cells. The molecular basis for antigenicity of the GD2 mimetic peptide, established by molecular modeling and mutagenesis studies, led to the generation of a 47-LDA mutant with an increased mimicry to GD2. Immunization of mice with peptide 47-LDA-encoded plasmid DNA elicited GD2 cross-reactive IgG antibody responses, which were increased on subsequent boost with GD2 ganglioside. The vaccine-induced antibodies recognized GD2-positive tumor cells, mediated complement-dependent cytotoxicity, and exhibited protection against s.c. human GD2-positive melanoma growth in the severe combined immunodeficient mouse xenograft model. The results from our studies provide insights into approaches for boosting GD2 cross-reactive IgG antibody responses by minigene vaccination with a protective epitope of GD2 ganglioside.

  17. Sialic Acids in the Brain: Gangliosides and Polysialic Acid in Nervous System Development, Stability, Disease, and Regeneration

    PubMed Central

    Gerardy-Schahn, Rita; Hildebrandt, Herbert

    2014-01-01

    Every cell in nature carries a rich surface coat of glycans, its glycocalyx, which constitutes the cell's interface with its environment. In eukaryotes, the glycocalyx is composed of glycolipids, glycoproteins, and proteoglycans, the compositions of which vary among different tissues and cell types. Many of the linear and branched glycans on cell surface glycoproteins and glycolipids of vertebrates are terminated with sialic acids, nine-carbon sugars with a carboxylic acid, a glycerol side-chain, and an N-acyl group that, along with their display at the outmost end of cell surface glycans, provide for varied molecular interactions. Among their functions, sialic acids regulate cell-cell interactions, modulate the activities of their glycoprotein and glycolipid scaffolds as well as other cell surface molecules, and are receptors for pathogens and toxins. In the brain, two families of sialoglycans are of particular interest: gangliosides and polysialic acid. Gangliosides, sialylated glycosphingolipids, are the most abundant sialoglycans of nerve cells. Mouse genetic studies and human disorders of ganglioside metabolism implicate gangliosides in axon-myelin interactions, axon stability, axon regeneration, and the modulation of nerve cell excitability. Polysialic acid is a unique homopolymer that reaches >90 sialic acid residues attached to select glycoproteins, especially the neural cell adhesion molecule in the brain. Molecular, cellular, and genetic studies implicate polysialic acid in the control of cell-cell and cell-matrix interactions, intermolecular interactions at cell surfaces, and interactions with other molecules in the cellular environment. Polysialic acid is essential for appropriate brain development, and polymorphisms in the human genes responsible for polysialic acid biosynthesis are associated with psychiatric disorders including schizophrenia, autism, and bipolar disorder. Polysialic acid also appears to play a role in adult brain plasticity

  18. Database and data analysis application for structural characterization of gangliosides and sulfated glycosphingolipids by negative ion mass spectrometry.

    PubMed

    Rožman, Marko; Fabris, Dragana; Mrla, Tomislav; Vukelić, Zeljka

    2014-12-05

    Gangliosides and sulfated glycosphingolipids, as building and functional components of animal cell membranes, participate in cell-to-cell interactions and signaling, but also in changes of cell architecture due to different pathophysiological events. In order to enable higher throughput and to facilitate structural characterization of gangliosides/sulfo-glycosphingolipids (GSL) and their neutral GSL counterparts by negative ion mass spectrometry (MS) and tandem MS techniques, a database and data analysis application have been developed. In silico developed glycosphingolipid database considers a high diversity of ceramide compositions, several sialic acid types (N-acetylneuraminic acid, N-glycolylneuraminic acid and 2-keto-3-deoxynononic acid) as well as possible additional substitutions/modifications of glycosphingolipids, such as O-acetylation, de-N-acetylation, fucosylation, glucuronosylation, sulfation, attachment of repeating terminal hexose-N-acetylhexosamine- (Hex-HexNAc-)1-6 extension, and possible lactone forms. Data analysis application, named GSL-finder, enables correlation of negative ion MS and/or low-energy tandem MS spectra with the database structures. The GSL-database construction and the GSL-finder application searching rules are explained. Validation conducted on GD1a fraction as well as on complex mixtures of native gangliosides isolated from different mammalian brain tissues (human fetal and adult brain, and calf brain tissue) demonstrated agreement with previous studies. Plain, fast, and automated routine for structural characterization of gangliosides/sulfated glycosphingolipids and their neutral GSL counterparts described here could facilitate and improve mass spectrometric analysis of complex glycosphingolipid mixtures originating from variety of normal and pathological biomaterial, where it is known that distinctive changes in glycosphingolipid composition occur.

  19. Construction of a hybrid β-hexosaminidase subunit capable of forming stable homodimers that hydrolyze GM2 ganglioside in vivo

    PubMed Central

    Tropak, Michael B; Yonekawa, Sayuri; Karumuthil-Melethil, Subha; Thompson, Patrick; Wakarchuk, Warren; Gray, Steven J; Walia, Jagdeep S; Mark, Brian L; Mahuran, Don

    2016-01-01

    Tay-Sachs or Sandhoff disease result from mutations in either the evolutionarily related HEXA or HEXB genes encoding respectively, the α- or β-subunits of β-hexosaminidase A (HexA). Of the three Hex isozymes, only HexA can interact with its cofactor, the GM2 activator protein (GM2AP), and hydrolyze GM2 ganglioside. A major impediment to establishing gene or enzyme replacement therapy based on HexA is the need to synthesize both subunits. Thus, we combined the critical features of both α- and β-subunits into a single hybrid µ-subunit that contains the α-subunit active site, the stable β-subunit interface and unique areas in each subunit needed to interact with GM2AP. To facilitate intracellular analysis and the purification of the µ-homodimer (HexM), CRISPR-based genome editing was used to disrupt the HEXA and HEXB genes in a Human Embryonic Kidney 293 cell line stably expressing the µ-subunit. In association with GM2AP, HexM was shown to hydrolyze a fluorescent GM2 ganglioside derivative both in cellulo and in vitro. Gene transfer studies in both Tay-Sachs and Sandhoff mouse models demonstrated that HexM expression reduced brain GM2 ganglioside levels. PMID:26966698

  20. Soluble Aβ oligomers are rapidly sequestered from brain ISF in vivo and bind GM1 ganglioside on cellular membranes

    PubMed Central

    Hong, Soyon; Ostaszewski, Beth L.; Yang, Ting; O'Malley, Tiernan T.; Jin, Ming; Yanagisawa, Katsuhiko; Li, Shaomin; Bartels, Tim; Selkoe, Dennis J.

    2014-01-01

    SUMMARY Soluble Aβ oligomers contribute importantly to synaptotoxicity in Alzheimer's disease, but their dynamics in vivo remain unclear. Here, we found that soluble Aβ oligomers were sequestered from brain interstitial fluid onto brain membranes much more rapidly than non-toxic monomers and were recovered in part as bound to GM1 ganglioside on membranes. Aβ oligomers bound strongly to GM1 ganglioside, and blocking the sialic acid residue on GM1 decreased oligomer-mediated LTP impairment in mouse hippocampal slices. In a hAPP transgenic mouse model, substantial levels of GM1-bound Aβ42 were recovered from brain membrane fractions. We also detected GM1-bound Aβ in human CSF, and its levels correlated with Aβ42, suggesting its potential as a biomarker of Aβ-related membrane dysfunction. Together, these findings highlight a novel mechanism whereby hydrophobic Aβ oligomers become sequestered onto GM1 ganglioside and presumably other lipids on neuronal membranes, where they may induce progressive functional and structural changes. PMID:24685176

  1. Construction of a hybrid β-hexosaminidase subunit capable of forming stable homodimers that hydrolyze GM2 ganglioside in vivo.

    PubMed

    Tropak, Michael B; Yonekawa, Sayuri; Karumuthil-Melethil, Subha; Thompson, Patrick; Wakarchuk, Warren; Gray, Steven J; Walia, Jagdeep S; Mark, Brian L; Mahuran, Don

    2016-01-01

    Tay-Sachs or Sandhoff disease result from mutations in either the evolutionarily related HEXA or HEXB genes encoding respectively, the α- or β-subunits of β-hexosaminidase A (HexA). Of the three Hex isozymes, only HexA can interact with its cofactor, the GM2 activator protein (GM2AP), and hydrolyze GM2 ganglioside. A major impediment to establishing gene or enzyme replacement therapy based on HexA is the need to synthesize both subunits. Thus, we combined the critical features of both α- and β-subunits into a single hybrid µ-subunit that contains the α-subunit active site, the stable β-subunit interface and unique areas in each subunit needed to interact with GM2AP. To facilitate intracellular analysis and the purification of the µ-homodimer (HexM), CRISPR-based genome editing was used to disrupt the HEXA and HEXB genes in a Human Embryonic Kidney 293 cell line stably expressing the µ-subunit. In association with GM2AP, HexM was shown to hydrolyze a fluorescent GM2 ganglioside derivative both in cellulo and in vitro. Gene transfer studies in both Tay-Sachs and Sandhoff mouse models demonstrated that HexM expression reduced brain GM2 ganglioside levels.

  2. Restoring GM1 ganglioside expression ameliorates axonal outgrowth inhibition and cognitive impairments induced by blast traumatic brain injury

    PubMed Central

    Rubovitch, Vardit; Zilberstein, Yael; Chapman, Joab; Schreiber, Shaul; Pick, Chaim G.

    2017-01-01

    Blast induced traumatic brain injury (B-TBI) may cause various degrees of cognitive and behavioral disturbances but the exact brain pathophysiology involved is poorly understood. It was previously suggested that ganglioside alteration on the axon surface as well as axonal regenerating inhibitors (ARIs) such as myelin associated glycoprotein (MAG) were involved in axonal outgrowth inhibition (AOI), leading to brain damage. GM1 ganglioside content in the brain was significantly reduced while GD1 ganglioside was not affected. The axonal regeneration was also reduced as seen by the phosphorylated NF-H expression. Moreover, B-TBI induced a significant elevation in MAG expression in the brains of the injured mice. The blast injured mice exhibited a significant decline in spatial memory as seen by the Y-maze test. In addition, the injured mice showed pronounced damage to the visual memory (as evaluated by the Novel object recognition test). A single low dose of GM1 (2 mg/kg; IP), shortly after the injury, prevented both the cognitive and the cellular changes in the brains of the injured mice. These results enlighten part of the complicated mechanism that underlies the damage induced by B-TBI and may also suggest a potential new treatment strategy for brain injuries. PMID:28112258

  3. Generation and characterization of an anti-idiotype monoclonal antibody related to GM3(NeuGc) ganglioside.

    PubMed

    Rodríguez, Mabel; Llanes, Leticia; Pérez, Alexis; Pérez, Rolando; Vázquez, Ana María

    2003-10-01

    The 14F7 monoclonal antibody (MAb), IgG1 isotype, which reacts specifically to GM3(NeuGc) ganglioside induced a specific IgG anti-idiotypic antibody (Ab2) response in syngeneic mice when it was administered coupled with KLH and in the presence of Freund's adjuvant. Spleen cells from these mice were used in somatic-cell hybridization experiments using the murine myeloma cell line P3-X63-Ag8 653 as fusion partner. An IgG1 Ab2 MAb was selected. This Ab2 MAb, called 4G9, was able to block the binding of 14F7 MAb to GM3(NeuGc) ganglioside and developed a strong IgG anti-anti-idiotypic antibody (Ab3) response, when injected into syngeneic mice. These Ab3 antibodies were characterized to bear 14F7 MAb idiotopes, but did not have the same specificity as 14F7 MAb. In the other hand, a very specific anti-NeuGc-containing ganglioside response was generated in chickens immunized with this Ab2 MAb, thus behaving, in this species as an "internal image" antibody.

  4. Prospective study on anti‐ganglioside antibodies in childhood Guillain–Barré syndrome

    PubMed Central

    Schessl, J; Koga, M; Funakoshi, K; Kirschner, J; Muellges, W; Weishaupt, A; Gold, R; Korinthenberg, R

    2007-01-01

    Background Antiganglioside antibodies have been reported to play a part in the pathophysiology of Guillain–Barré syndrome (GBS). Aims To investigate the prevalence and correlation of anti‐ganglioside antibodies with clinical data in children with GBS in a multicentre clinical trial. Methods Immunoglobin (Ig)G and IgM to GM1, GM1b, GD1a, GalNAc–GD1a, GD1b, GT1a, and GQ1b were measured by ELISA in sera obtained before treatment. In addition, serological testing for Campylobacter jejuni was carried out. In parallel, a group of adults with GBS and a control group of children without GBS or other inflammatory diseases were evaluated. Results Sera from 63 children with GBS, 36 adults with GBS and 41 children without GBS were evaluated. Four of the children with GBS showed positive IgG to GM1, in one case combined with anti‐GalNAc–GD1a and in one with anti‐GD1b. Two others showed isolated positive IgG to GD1b and GT1a. One showed increased anti‐GalNAc–GD1a IgM. In 5 of the 63 children, serological evidence of a recent infection with C jejuni was found, and this correlated significantly with the raised antibodies (p = 0.001). In the control group without GBS, no child showed positive IgG, but one showed anti‐GalNAc–GD1a IgM. Compared with the adults with GBS, the frequency of antibodies in children was insignificantly lower. In our study, patients with positive antibodies did not show a more severe GBS course or worse outcome than those who were seronegative, and we could not show an increased incidence of axonal dysfunction. Conclusions In some children with GBS, one can detect raised IgG against various gangliosides, similar to that in adults. A recent infection with C jejuni is markedly associated with the presence of these antibodies. However, in contrast with what has been reported in adults, in this study we were unable to show a negative effect of these findings on the clinical course. PMID:16920757

  5. Near-ultraviolet absorption spectra and crystal-field analysis of Gd3+ in Na3[Gd(C4H4O5)3].2NaClO4.6H2O

    NASA Astrophysics Data System (ADS)

    Stephens, Eileen M.; Metcalf, David H.; Berry, Mary T.; Richardson, F. S.

    1991-11-01

    Optical absorption spectra between 32 000 and 41 000 cm-1 are reported for Gd3+ in trigonal Na3[Gd(oxydiacetate)3].2NaClO4.6H2O at temperatures between 10 and 298 K. Fifty-eight of the 63 crystal-field levels split out of the 6PJ(J=7/2, 5/2, and 3/2), 6IJ(J=7/2, 9/2, 17/2, 11/2, 15/2, and 13/2), and 6DJ(J=9/2, 1/2, 7/2, 3/2, and 5/2) multiplets of the Gd3+ 4f7 electronic configuration are located and assigned from the low-temperature spectra, and these energy levels are analyzed in terms of a parametrized Hamiltonian that reflects D3 site symmetry at the Gd3+ ions. Parametric fits of calculated to empirical-energy-level data yield a rms deviation of 6.3 cm-1 (between calculated and observed energies). Eigenvectors of the parametrized Hamiltonian are used in calculations of oscillator strengths for all transitions that originate from the 8S7/2 (ground) multiplet and terminate on crystal-field levels of the 6PJ, 6IJ, and 6DJ multiplet manifolds. Spectra simulations based on these calculated oscillator strengths are presented, and comparisons between the simulated spectra and experimentally observed spectra show excellent agreement with respect to intensity distributions both within and between the various multiplet-to-multiplet transition manifolds. Variable-temperature absorption measurements carried out between 10 and 298 K showed only very small changes in J-multiplet baricenter energies, crystal-field-splitting energies (within J-multiplet manifolds), and transition intensity distributions. Disparities between the energy-level structure deduced in the present study and that proposed in another recently published study of Na3[Gd(oxydiacetate)3].2NaClO4.6H2O [Phys. Rev. B 41, 10 911 (1990)] are discussed. This previous study of Kundu, Banerjee, and Chowdhury was based on two-photon luminescence excitation measurements that have special significance for elucidating two-photon-absorption intensity mechanisms of 4f-4f transitions in noncentrosymmetric lanthanide

  6. Free carrier absorption in self-activated PbWO4 and Ce-doped Y3(Al0.25Ga0.75)3O12 and Gd3Al2Ga3O12 garnet scintillators

    NASA Astrophysics Data System (ADS)

    Auffray, E.; Korjik, M.; Lucchini, M. T.; Nargelas, S.; Sidletskiy, O.; Tamulaitis, G.; Tratsiak, Y.; Vaitkevičius, A.

    2016-08-01

    Nonequilibrium carrier dynamics in the scintillators prospective for fast timing in high energy physics and medical imaging applications was studied. The time-resolved free carrier absorption investigation was carried out to study the dynamics of nonequilibrium carriers in wide-band-gap scintillation materials: self-activated led tungstate (PbWO4, PWO) ant two garnet crystals, GAGG:Ce and YAGG:Ce. It was shown that free electrons appear in the conduction band of PWO and YAGG:Ce crystals within a sub-picosecond time scale, while the free holes in GAGG:Ce appear due to delocalization from Gd3+ ground states to the valence band within a few picoseconds after short-pulse excitation. The influence of Gd ions on the nonequilibrium carrier dynamics is discussed on the base of comparison the results of the free carrier absorption in GAGG:Ce containing gadolinium and in YAGG without Gd in the host lattice.

  7. Expression of B4GALNT1, an essential glycosyltransferase for the synthesis of complex gangliosides, suppresses BACE1 degradation and modulates APP processing

    PubMed Central

    Yamaguchi, Tokiaki; Yamauchi, Yoshio; Furukawa, Keiko; Ohmi, Yuhsuke; Ohkawa, Yuki; Zhang, Qing; Okajima, Tetsuya; Furukawa, Koichi

    2016-01-01

    Alzheimer’s disease (AD) is the most prevalent form of dementia characterized by the extracellular accumulation of amyloid β (Aβ) peptides, which are produced by proteolytic cleavages of amyloid precursor protein (APP). Gangliosides are involved in AD pathophysiology including Aβ deposition and APP processing, yet the detailed mechanisms are not fully understood. Here we examined how changes in the carbohydrate moiety of gangliosides alter APP processing in human melanoma cells, neuroectoderm-derived cells. We showed that forced expression of GD2, GM2 or GM1 (by introducing B4GALNT1 cDNA into cells not expressing this glycosyltransferase) results in increases of α- and β-site cleavages of APP with a prominent increase in β-cleavage. We also showed that β-site APP cleaving enzyme 1 (BACE1) protein is highly protected from the degradation in cells expressing these gangliosides, thereby increasing the expression of this protein. Unexpectedly, adding gangliosides exogenously altered neither BACE1 levels nor β-site cleavage. The stabilisation of BACE1 protein led to the increase of this protein in lipid rafts, where BACE1 processes APP. Based on the current results, we propose a hitherto undisclosed link between ganglioside expression and AD; the expression of B4GALNT1 positively regulates the β-site cleavage by mainly inhibiting the lysosomal degradation of BACE1 protein. PMID:27687691

  8. Membrane lipids regulate ganglioside GM2 catabolism and GM2 activator protein activity[S

    PubMed Central

    Anheuser, Susi; Breiden, Bernadette; Schwarzmann, Günter; Sandhoff, Konrad

    2015-01-01

    Ganglioside GM2 is the major lysosomal storage compound of Tay-Sachs disease. It also accumulates in Niemann-Pick disease types A and B with primary storage of SM and with cholesterol in type C. Reconstitution of GM2 catabolism with β-hexosaminidase A and GM2 activator protein (GM2AP) at uncharged liposomal surfaces carrying GM2 as substrate generated only a physiologically irrelevant catabolic rate, even at pH 4.2. However, incorporation of anionic phospholipids into the GM2 carrying liposomes stimulated GM2 hydrolysis more than 10-fold, while the incorporation of plasma membrane stabilizing lipids (SM and cholesterol) generated a strong inhibition of GM2 hydrolysis, even in the presence of anionic phospholipids. Mobilization of membrane lipids by GM2AP was also inhibited in the presence of cholesterol or SM, as revealed by surface plasmon resonance studies. These lipids also reduced the interliposomal transfer rate of 2-NBD-GM1 by GM2AP, as observed in assays using Förster resonance energy transfer. Our data raise major concerns about the usage of recombinant His-tagged GM2AP compared with untagged protein. The former binds more strongly to anionic GM2-carrying liposomal surfaces, increases GM2 hydrolysis, and accelerates intermembrane transfer of 2-NBD-GM1, but does not mobilize membrane lipids. PMID:26175473

  9. Bis(monoacylglycero)phosphate and ganglioside GM1 spontaneously form small homogeneous vesicles at specific concentrations

    SciTech Connect

    Chebukati, Janetricks N.; Goff, Philip C.; Frederick, Thomas E.; Fanucci, Gail E.

    2010-04-09

    The morphology and size of hydrated lipid dispersions of bis(monoacylglycero)phosphate (BMP) mixed with varying mole percentages of the ganglioside GM1 were investigated by dynamic light scattering (DLS) and transmission electron microscopy (TEM). Electron paramagnetic resonance (EPR) spectroscopy of these same mixtures, doped at 0.5 mol% with doxyl labeled lipids, was used to investigate acyl-chain packing. Results show that for 20-30% GM1, hydrated BMP:GM1 mixtures spontaneously form small spherical vesicles with diameters {approx}100 nm and a narrow size distribution profile. For other concentrations of GM1, hydrated dispersions with BMP have non-spherical shapes and heterogeneous size profiles, with average vesicle diameters >400 nm. All samples were prepared at pH 5.5 to mimic the lumen acidity of the late endosome where BMP is an essential component of intraendosomal vesicle budding, lipid sorting and trafficking. These findings indicate that GM1 and BMP under a limited concentration range spontaneously form small vesicles of homogeneous size in an energy independent manner without the need of protein templating. Because BMP is essential for intraendosomal vesicle formation, these results imply that lipid-lipid interactions may play a critical role in the endosomal process of lipid sorting and trafficking.

  10. Ganglioside embedded in reconstituted lipoprotein binds cholera toxin with elevated affinity.

    PubMed

    Bricarello, Daniel A; Mills, Emily J; Petrlova, Jitka; Voss, John C; Parikh, Atul N

    2010-09-01

    The ability to exogenously present cell-surface receptors in high-affinity conformations in a synthetic system offers an opportunity to provide host cells with protection from pathogenic toxins. This strategy requires improvement of the synthetic receptor binding affinity against its native counterpart, particularly with polyvalent toxins where clustering of membrane receptors can hinder binding. Here we demonstrate that reconstituted lipoprotein, nanometer-sized discoidal lipid bilayers bounded by apolipoprotein and functionalized by incorporation of pathogen receptors, provides a means to enhance toxin-receptor binding through molecular-level control over the receptor microenvironment (specifically, its rigidity, composition, and heterogeneity). Using a Foerster Resonance Energy Transfer (FRET)-based assay, we found that reconstituted lipoprotein incorporating low concentrations of ganglioside monosialotetrahexosylganglioside (GM1) binds polymeric cholera toxin with significantly higher affinity than liposomes or supported lipid bilayers, most likely a result of the enhanced control over receptor clustering provided by the lipoprotein platform. Using wide-area epifluorescence, we found that this enhanced binding capacity can be effectively utilized to divert cholera toxin away from populations of healthy mammalian cells. In summary, we found that reconstitutions of high-density lipoprotein can be engineered to include specific pathogen receptors; that their pathogen binding affinity is altered, presumably due to attenuation of receptor aggregation; and that these assemblies are effective at protecting cells from biological toxins.

  11. Membrane lipids regulate ganglioside GM2 catabolism and GM2 activator protein activity.

    PubMed

    Anheuser, Susi; Breiden, Bernadette; Schwarzmann, Günter; Sandhoff, Konrad

    2015-09-01

    Ganglioside GM2 is the major lysosomal storage compound of Tay-Sachs disease. It also accumulates in Niemann-Pick disease types A and B with primary storage of SM and with cholesterol in type C. Reconstitution of GM2 catabolism with β-hexosaminidase A and GM2 activator protein (GM2AP) at uncharged liposomal surfaces carrying GM2 as substrate generated only a physiologically irrelevant catabolic rate, even at pH 4.2. However, incorporation of anionic phospholipids into the GM2 carrying liposomes stimulated GM2 hydrolysis more than 10-fold, while the incorporation of plasma membrane stabilizing lipids (SM and cholesterol) generated a strong inhibition of GM2 hydrolysis, even in the presence of anionic phospholipids. Mobilization of membrane lipids by GM2AP was also inhibited in the presence of cholesterol or SM, as revealed by surface plasmon resonance studies. These lipids also reduced the interliposomal transfer rate of 2-NBD-GM1 by GM2AP, as observed in assays using Förster resonance energy transfer. Our data raise major concerns about the usage of recombinant His-tagged GM2AP compared with untagged protein. The former binds more strongly to anionic GM2-carrying liposomal surfaces, increases GM2 hydrolysis, and accelerates intermembrane transfer of 2-NBD-GM1, but does not mobilize membrane lipids.

  12. Anti-GM2 ganglioside antibodies are a biomarker for acute canine polyradiculoneuritis

    PubMed Central

    Bianchi, Ezio; Dondi, Maurizio; Penderis, Jacques; Cappell, Joanna; Burgess, Karl; Matiasek, Kaspar; McGonigal, Rhona; Willison, Hugh J.

    2016-01-01

    Acute canine polyradiculoneuritis (ACP) is considered to be the canine equivalent of the human peripheral nerve disorder Guillain-Barré syndrome (GBS); an aetiological relationship, however, remains to be demonstrated. In GBS, anti-glycolipid antibodies (Abs) are considered as important disease mediators. To address the possibility of common Ab biomarkers, the sera of 25 ACP dogs, 19 non-neurological, and 15 epileptic control dogs were screened for IgG Abs to 10 glycolipids and their 1 : 1 heteromeric complexes using combinatorial glycoarrays. Anti-GM2 ganglioside Abs were detected in 14/25 ACP dogs, and anti-GA1 Abs in one further dog. All controls except for one were negative for anti-glycolipid Abs. In this cohort of cases and controls, the glycoarray screen reached a diagnostic sensitivity of 60% and a specificity of 97%; a lower sensitivity (32%) was reported using a conventional glycolipid ELISA. To address the possible pathogenic role for anti-GM2 Abs in ACP, we identified GM2 in canine sciatic nerve by both mass spectrometry and thin layer chromatography overlay. In immunohistological studies, GM2 was localized predominantly to the abaxonal Schwann cell membrane. The presence of anti-GM2 Abs in ACP suggests that it may share a similar pathophysiology with GBS, for which it could thus be considered a naturally occurring animal model. PMID:23521648

  13. Effects of Methylprednisolone And Ganglioside GM-1 on a Spinal Lesion: A Functional Analysis

    PubMed Central

    Carvalho, Márcio Oliveira Penna; de Barros Filho, Tarcisio Eloy Pessoa; Tebet, Marcos Antonio

    2008-01-01

    OBJECTIVES The pharmacological effects of methylprednisolone (MP) and ganglioside GM-1 on spinal injuries have been thoroughly investigated, but only a few studies have evaluated the interaction between these two drugs. METHODS Twenty-four Wistar rats were subjected to contusive injury of the spinal cord produced by the NYU system. These animals were divided into four groups: group I was injected with MP; group II was injected with GM-1; group III was injected with MP together with GM-1; and group control received physiological serum. The animals were evaluated with regard to their recovery of locomotive function by means of the BBB test on the second, seventh and fourteenth days after receiving the contusive injury to the spinal cord. They were sacrificed on the fourteenth day. RESULTS This study demonstrated that the MP and GM-1 groups presented functional results that were better than those of the control group, although the enhanced recovery of group II (GM-1) relative to the control group was not statistically significant (p>0.05). The most notable recovery of locomotive function was observed in the group that received MP alone (p<0.05). The group that received MP together with GM-1 presented results that were better than those of the control group (p<0.05). CONCLUSION Administration of methylprednisolone alone or with GM-1 was shown to be effective for recovery of locomotive function. Combined administration of these drugs resulted in better outcomes than administration of methylprednisolone alone. PMID:18568249

  14. Comparative study of the Mn4+2E → 4A2 luminescence in isostructural RE2Sn2O7:Mn4+ pyrochlores (RE3+ = Y3+, Lu3+ or Gd3+)

    NASA Astrophysics Data System (ADS)

    Senden, Tim; Broers, Fréderique T. H.; Meijerink, Andries

    2016-10-01

    Red emitting Mn4+-doped crystalline materials have potential for application in light emitting devices and therefore it is important to understand how the optical properties of Mn4+ are influenced by the host lattice the Mn4+ ions are situated in. In this work we investigate the effect of the host cations in the second coordination sphere on the Mn4+ emission by studying the luminescence of Mn4+ ions doped into three isostructural rare earth (RE) stannate RE2Sn2O7 pyrochlores (RE3+ = Y3+, Lu3+ or Gd3+). It is found that the energies of the Mn4+4T1 and 4T2 states significantly increase with decreasing Mn4+-O2- distance, whereas the energy of the 2E level shows a small shift to higher energies from RE3+ = Gd3+ to Lu3+ to Y3+. The observed trend for the 2E level energy is not related to the size of the RE3+ ion and is not in line with theoretical calculations reported previously. Low temperature emission spectra of the RE2Sn2O7:Mn4+ phosphors reveal that only asymmetrical vibronic modes couple to the 2E → 4A2 transition and furthermore show there is significant and unexpected local disorder for Mn4+ in Gd2Sn2O7 that is not observed for Mn4+ in the other hosts. Photoluminescence decay measurements demonstrate that the luminescence of RE2Sn2O7:Mn4+ is strongly quenched below room temperature which is assigned to non-radiative relaxation via a low-lying O2- → Mn4+ charge-transfer state.

  15. Size-Tunable and Monodisperse Tm3+/Gd3+-Doped Hexagonal NaYbF4 Nanoparticles with Engineered Efficient Near Infrared-to-Near Infrared Upconversion for In Vivo Imaging

    PubMed Central

    2015-01-01

    Hexagonal NaYbF4:Tm3+ upconversion nanoparticles hold promise for use in high contrast near-infrared-to-near-infrared (NIR-to-NIR) in vitro and in vivo bioimaging. However, significant hurdles remain in their preparation and control of their morphology and size, as well as in enhancement of their upconversion efficiency. Here, we describe a systematic approach to produce highly controlled hexagonal NaYbF4:Tm3+ nanoparticles with superior upconversion. We found that doping appropriate concentrations of trivalent gadolinium (Gd3+) can convert NaYbF4:Tm3+ 0.5% nanoparticles with cubic phase and irregular shape into highly monodisperse NaYbF4:Tm3+ 0.5% nanoplates or nanospheres in a pure hexagonal-phase and of tunable size. The intensity and the lifetime of the upconverted NIR luminescence at 800 nm exhibit a direct dependence on the size distribution of the resulting nanoparticles, being ascribed to the varied surface-to-volume ratios determined by the different nanoparticle size. Epitaxial growth of a thin NaYF4 shell layer of ∼2 nm on the ∼22 nm core of hexagonal NaYbF4:Gd3+ 30%/Tm3+ 0.5% nanoparticles resulted in a dramatic 350 fold NIR upconversion efficiency enhancement, because of effective suppression of surface-related quenching mechanisms. In vivo NIR-to-NIR upconversion imaging was demonstrated using a dispersion of phospholipid-polyethylene glycol (DSPE-PEG)-coated core/shell nanoparticles in phosphate buffered saline. PMID:25027118

  16. Atomic-resolution conformational analysis of the GM3 ganglioside in a lipid bilayer and its implications for ganglioside–protein recognition at membrane surfaces

    PubMed Central

    DeMarco, Mari L; Woods, Robert J

    2009-01-01

    Eukaryotic cells depend on external surface markers, such as gangliosides, to recognize and bind various other molecules as part of normal growth and maturation. The localization of gangliosides in the outer leaflet of the plasma membrane, also make them targets for pathogens trying to invade the host cells. Since ganglioside-mediated interactions are critical to both beneficial and pathological processes, much effort has been directed at determining the 3D structures of their carbohydrate head groups; however, technical difficulties have generally prevented the characterization of the head group in intact membrane-bound gangliosides. Determining the 3D structure and presentation of gangliosides at the surface of membranes is important in understanding how cells interact with their local environment. Here, we employ all-atom explicit solvent molecular dynamics (MD) simulations, using the GLYCAM06 force field, to model the conformation and dynamics of ganglioside GM3 (α-Neu5Ac-(2-3)-β-Gal-(1-4)-β-Glc-ceramide) in a DMPC lipid bilayer. By comparison with MD simulations of the carbohydrate head-group fragment of GM3 alone, it was possible to quantify and characterize the extent of changes in head-group presentation and dynamics associated with membrane anchoring. The accuracy of data from the MD simulations was determined by comparison to NMR and crystallographic data for the head group in solution and for GM3 in membrane-mimicking environments. The experimentally consistent model of GM3, in a lipid bilayer, was then used to model the recognition of GM3 at the cell surface by known protein receptors. PMID:19056784

  17. Ganglioside GM2 mediates migration of tumor cells by interacting with integrin and modulating the downstream signaling pathway.

    PubMed

    Kundu, Manjari; Mahata, Barun; Banerjee, Avisek; Chakraborty, Sohini; Debnath, Shibjyoti; Ray, Sougata Sinha; Ghosh, Zhumur; Biswas, Kaushik

    2016-07-01

    The definitive role of ganglioside GM2 in mediating tumor-induced growth and progression is still unknown. Here we report a novel role of ganglioside GM2 in mediating tumor cell migration and uncovered its mechanism. Data shows differential expression levels of GM2-synthase as well as GM2 in different human cancer cells. siRNA mediated knockdown of GM2-synthase in CCF52, A549 and SK-RC-26B cells resulted in significant inhibition of tumor cell migration as well as invasion in vitro without affecting cellular proliferation. Over-expression of GM2-synthase in low-GM2 expressing SK-RC-45 cells resulted in a consequent increase in migration thus confirming the potential role GM2 and its downstream partners play in tumor cell migration and motility. Further, treatment of SK-RC-45 cells with exogenous GM2 resulted in a dramatic increase in migratory and invasive capacity with no change in proliferative capacity, thereby confirming the role of GM2 in tumorigenesis specifically by mediating tumor migration and invasion. Gene expression profiling of GM2-synthase silenced cells revealed altered expression of several genes involved in cell migration primarily those controlling the integrin mediated signaling. GM2-synthase knockdown resulted in decreased phosphorylation of FAK, Src as well as Erk, while over-expression and/or exogenous GM2 treatment caused increased FAK and Erk phosphorylation respectively. Again, GM2 mediated invasion and Erk phosphorylation is blocked in integrin knockdown SK-RC-45 cells, thus confirming that GM2 mediated migration and phosphorylation of Erk is integrin dependent. Finally, confocal microscopy suggested co-localization while co-immunoprecipitation and surface plasmon resonance (SPR) confirmed direct interaction of membrane bound ganglioside, GM2 with the integrin receptor.

  18. Gangliosides inhibit bee venom melittin cytotoxicity but not phospholipase A{sub 2}-induced degranulation in mast cells

    SciTech Connect

    Nishikawa, Hirofumi; Kitani, Seiichi

    2011-05-01

    Sting accident by honeybee causes severe pain, inflammation and allergic reaction through IgE-mediated anaphylaxis. In addition to this hypersensitivity, an anaphylactoid reaction occurs by toxic effects even in a non-allergic person via cytolysis followed by similar clinical manifestations. Auto-injectable epinephrine might be effective for bee stings, but cannot inhibit mast cell lysis and degranulation by venom toxins. We used connective tissue type canine mast cell line (CM-MC) for finding an effective measure that might inhibit bee venom toxicity. We evaluated degranulation and cytotoxicity by measurement of {beta}-hexosaminidase release and MTT assay. Melittin and crude bee venom induced the degranulation and cytotoxicity, which were strongly inhibited by mono-sialoganglioside (G{sub M1}), di-sialoganglioside (G{sub D1a}) and tri-sialoganglioside (G{sub T1b}). In contrast, honeybee venom-derived phospholipase A{sub 2} induced the net degranulation directly without cytotoxicity, which was not inhibited by G{sub M1}, G{sub D1a} and G{sub T1b}. For analysis of distribution of G{alpha}{sub q} and G{alpha}{sub i} protein by western blotting, lipid rafts were isolated by using discontinuous sucrose gradient centrifuge. Melittin disrupted the localization of G{alpha}{sub q} and G{alpha}{sub i} at lipid raft, but gangliosides stabilized the rafts. As a result from this cell-based study, bee venom-induced anaphylactoid reaction can be explained with melittin cytotoxicity and phospholipase A{sub 2}-induced degranulation. Taken together, gangliosides inhibit the effect of melittin such as degranulation, cytotoxicity and lipid raft disruption but not phospholipase A{sub 2}-induced degranulation in mast cells. Our study shows a potential of gangliosides as a therapeutic tool for anaphylactoid reaction by honeybee sting.

  19. Degradation of membrane-bound ganglioside GM1. Stimulation by bis(monoacylglycero)phosphate and the activator proteins SAP-B and GM2-AP.

    PubMed

    Wilkening, G; Linke, T; Uhlhorn-Dierks, G; Sandhoff, K

    2000-11-17

    According to our hypothesis (Fürst, W., and Sandhoff, K. (1992) Biochim. Biophys. Acta 1126, 1-16) glycosphingolipids of the plasma membrane are digested after endocytosis as components of intraendosomal and intralysosomal vesicles and membrane structures. The lysosomal degradation of glycosphingolipids with short oligosaccharide chains by acid exohydrolases requires small, non-enzymatic cofactors, called sphingolipid activator proteins (SAPs). A total of five activator proteins have been identified as follows: namely the saposins SAP-A, -B, -C, and -D, which are derived from the single chain SAP-precursor protein (prosaposin), and the GM2 activator protein. A deficiency of prosaposin results in the storage of ceramide and sphingolipids with short oligosaccharide head groups. The loss of the GM2 activator protein blocks the degradation of the ganglioside GM2. The enzymatic hydrolysis of the ganglioside GM1 is catalyzed by beta-galactosidase, a water-soluble acid exohydrolase. The lack of ganglioside GM1 accumulation in patients suffering from either prosaposin or GM2 activator protein deficiency has led to the hypothesis that SAPs are not needed for the hydrolysis of the ganglioside GM1 in vivo. In this study we demonstrate that an activator protein is required for the enzymatic degradation of membrane-bound ganglioside GM1 and that both SAP-B and the GM2 activator protein significantly enhance the degradation of the ganglioside GM1 by acid beta-galactosidase in a liposomal, detergent-free assay system. These findings offer a possible explanation for the observation that no storage of the ganglioside GM1 has been observed in patients with either isolated prosaposin or isolated GM2 activator deficiency. We also demonstrate that anionic phospholipids such as bis(monoacylglycero)phosphate and phosphatidylinositol, which specifically occur in inner membranes of endosomes and in lysosomes, are essential for the activator-stimulated hydrolysis of the ganglioside GM1

  20. [The effect of alpha-liponic acid, vitamin B or gangliosides on the regeneration of traumatically damaged peripheral nerves in the rat. A comparative, morphometric study].

    PubMed

    Stotzem, C D; Mengs, U

    1988-05-01

    The sciatic nerve of male rats was crushed in accordance with a standardized method. To investigate the positive influence of different substances on nerve regeneration, the rats received daily injections of alpha-liponic acid, vitamin B or gangliosides. After 11 days the sciatic nerves were removed and the area distal to the crush site was analyzed histomorphometrically. Compared with the control group, there was only a slight increase in the number of regenerating fibres and their diameters following treatment with alpha-liponic acid or vitamin B. However, in the ganglioside-treated rats the differences, indicative of accelerated regeneration, were statistically significant.

  1. Co-localization of the Ganglioside GM1 and Cholesterol Detected by Secondary Ion Mass Spectrometry

    PubMed Central

    Lozano, Mónica M.; Liu, Zhao; Sunnick, Eva; Janshoff, Andreas; Kumar, Krishna; Boxer, Steven G.

    2013-01-01

    The characterization of the lateral organization of components in biological membranes and the evolution of this arrangement in response to external triggers remains a major challenge. The concept of lipid rafts is widely invoked, however, direct evidence of the existence of these ephemeral entities remains elusive. We report here the use of Secondary Ion Mass Spectrometry (SIMS) to image the cholesterol-dependent cohesive phase separation of the ganglioside GM1 into nano and micro-scale assemblies in a canonical lipid raft composition of lipids. This assembly of domains was interrogated in a model membrane system composed of palmitoyl sphingomyelin (PSM), cholesterol, and an unsaturated lipid (dioleoylphosphatidylcholine, DOPC). Orthogonal isotopic labeling of every lipid bilayer component and monofluorination of GM1 allowed generation of molecule specific images using a NanoSIMS. Simultaneous detection of six different ion species in SIMS, including secondary electrons, was used to generate ion ratio images whose signal intensity values could be correlated to composition through the use of calibration curves from standard samples. Images of this system provide the first direct, molecule specific, visual evidence for the co-localization of cholesterol and GM1 in supported lipid bilayers and further indicate the presence of three compositionally distinct phases: (1) the interdomain region; (2) micrometer-scale domains (d>3 μm); and, (3) nanometer-scale domains (d=100 nm − 1 μm) localized within the micrometer-scale domains and the interdomain region. PSM-rich, nanometer-scale domains prefer to partition within the more ordered, cholesterol-rich/DOPC-poor/GM1-rich micrometer-scale phase, while GM1-rich, nanometer-scale domains prefer to partition within the surrounding, disordered, cholesterol-poor/PSM-rich/DOPC-rich interdomain phase. PMID:23514537

  2. The Role of Ganglioside GM1 in Cellular Internalization Mechanisms of Poly(amidoamine) Dendrimers

    PubMed Central

    Hong, Seungpyo; Rattan, Rahul; Majoros, István J.; Mullen, Douglas G.; Peters, Jennifer L.; Shi, Xiangyang; Bielinska, Anna U.; Blanco, Luz; Orr, Bradford G.; Baker, James R.; Holl, Mark M. Banaszak

    2015-01-01

    Generation 7 (G7) poly(amidoamine) (PAMAM) dendrimers with amine, acetamide, and carboxylate end groups were prepared to investigate polymer/cell membrane interactions in vitro. G7 PAMAM dendrimers were used in this study because higher generation of dendrimers are more effective in permeabilization of cell plasma membranes and in the formation of nanoscale holes in supported lipid bilayers than smaller, lower generation dendrimers. Dendrimer-based conjugates were characterized by 1H NMR, UV/Vis spectroscopy, GPC, HPLC, and CE. Positively charged amine-terminated G7 dendrimers (G7-NH2) were observed to internalize into KB, Rat2 and C6 cells at a 200 nM concentration. By way of contrast, neither negatively charged G7 carboxylate-terminated dendrimers (G7-COOH) nor neutral acetamide-terminated G7 dendrimers (G7-Ac) associated with the cell plasma membrane or internalized under similar conditions. A series of in vitro experiments employing endocytic markers cholera toxin subunit B (CTB), transferrin, and GM1-pyrene were performed to further investigate mechanisms of dendrimer internalization into cells. G7-NH2 dendrimers co-localized with CTB, however, experiments with C6 cells indicated that internalization of G7-NH2 was not ganglioside GM1 dependent. The G7/CTB co-localization was thus ascribed to an artifact of direct interaction between the two species. The presence of GM1 in the membrane also had no effect upon XTT assays of cell viability or lactate dehydrogenase (LDH) assays of membrane permeability. PMID:19583240

  3. Neoglycolipid analogues of ganglioside G sub M1 as functional receptors of cholera toxin

    SciTech Connect

    Pacuszka, T.; Bradley, R.M.; Fishman, P.H. )

    1991-03-12

    The authors synthesized several lipid analogues of ganglioside G{sub M1} by attaching its oligosaccharide moiety (G{sub M1}OS) to aminophospholipids, aliphatic amines, and cholesteryl hemisuccinate. They incubated G{sub M1}-deficient rat glioma C6 cells with each of the derivatives as well as native G{sub M1} and assayed the cells for their ability to bind and respond to cholera toxin. On the basis of the observed increase in binding of {sup 125}I-labeled cholera toxin, it was apparent that the cells took up and initially incorporated most of the derivatives into the plasma membrane. In the case of the aliphatic amine derivatives, the ability to generate new toxin binding sites was dependent on chain length; whereas the C{sub 10} derivative was ineffective, C{sub 12} and higher analogues were effective. Increased binding was dependent on both the concentration of the neoglycolipid in the medium and the time of exposure. Cells pretreated with the various derivatives accumulated cyclic AMP in response to cholera toxin, but there were differences in their effectiveness. The cholesterol and long-chain aliphatic amine derivatives were more effective than native G{sub M1}, whereas the phospholipid derivatives were less effective. The distance between G{sub M1}OS and the phospholipid also appeared to influence its functional activity. The results indicate that although G{sub M1}OS provides the recognition site for the binding of cholera toxin, the nature of the lipid moiety plays an important role in the action of the toxin.

  4. Antidepressant-Like Effects of GM1 Ganglioside Involving the BDNF Signaling Cascade in Mice

    PubMed Central

    Song, Lu; Wang, Cheng-Niu; Zhang, Wei; Huang, Chao; Tong, Li-Juan

    2016-01-01

    Background: Depression is a serious psychiatric disorder that easily causes physical impairments and a high suicide rate. Monosialotetrahexosylganglioside is a crucial ganglioside for the central nervous system and has been reported to affect the function of the brain derived neurotrophic factor system. This study is aimed to evaluate whether monosialotetrahexosylganglioside has antidepressant-like effects. Methods: Antidepressant-like effects of monosialotetrahexosylganglioside were assessed in the chronic social defeat stress model of depression, and various behavioral tests were performed. Changes in the brain derived neurotrophic factor signaling pathway after chronic social defeat stress and monosialotetrahexosylganglioside treatment were also investigated. A tryptophan hydroxylase inhibitor and brain derived neurotrophic factor signaling inhibitors were used to determine the antidepressant mechanisms of monosialotetrahexosylganglioside. Results: Monosialotetrahexosylganglioside administration significantly reversed the chronic social defeat stress-induced reduction of sucrose preference and social interaction in mice and also prevented the increased immobility time in the forced swim test and tail suspension test. In addition, monosialotetrahexosylganglioside completely ameliorated the stress-induced dysfunction of brain derived neurotrophic factor signaling cascade in the hippocampus and medial prefrontal cortex, 2 regions closely involved in the pathophysiology of depression. Furthermore, the usage of brain derived neurotrophic factor signaling cascade inhibitors, K252a and anti-brain derived neurotrophic factor antibody, each abolished the antidepressant-like effects of monosialotetrahexosylganglioside, while the usage of a serotonin system inhibitor did not. Conclusions: Taken together, our findings suggest that monosialotetrahexosylganglioside indeed has antidepressant-like effects, and these effects were mediated through the activation of brain derived

  5. Interactions between the ganglioside GM1 and hexadecylphosphocholine (miltefosine) in monolayers at the air/water interface.

    PubMed

    Gómez-Serranillos, Isabel Rey; Miñones, José; Dynarowicz-Łatka, Patrycja; Iribarnegaray, Eduardo; Casas, Matilde

    2005-03-10

    The ganglioside, GM1, was studied as Langmuir monolayers at the air/water interface with surface pressure-area measurements in addition to Brewster angle microscopy. A characteristic plateau transition, observed on aqueous subphases of pH 2 and 6, 20 degrees C, at the surface pressure of ca. 20 mN/m, was attributed to the reorientation of GM1 polar group upon film compression. This transition was found to disappear at alkaline subphases (pH 10) due to the hydration of fully ionized polar group, hindering its reorientation. The interactions between GM1 and hexadecylphosphocholine (miltefosine) were investigated in mixed monolayers and analyzed with the mean molecular areas, excess areas of mixing and the excess free energy of mixing versus film composition plots. The monolayers stability, quantified by the collapse pressure values, as well as the strength of interaction was found to diminish in the following order: pH 6>pH 2>pH 10. The strongest interaction occurs for mixed films of miltefosine molar fraction, XM=0.7-0.8, especially at low pressure region, and are explained as being due to the surface complex formation of 3:1 or 4:1 (miltefosine:ganglioside) stoichiometry (XM=0.75 or 0.8, respectively).

  6. Ganglioside GM3 synthase depletion reverses neuropathic pain and small fiber neuropathy in diet-induced diabetic mice

    PubMed Central

    Jayaraj, Nirupa D; Wilson, Heather M; Ren, Dongjun; Flood, Kelsey; Wang, Xiao-Qi; Shum, Andrew; Miller, Richard J; Paller, Amy S

    2016-01-01

    Background Small fiber neuropathy is a well-recognized complication of type 2 diabetes and has been shown to be responsible for both neuropathic pain and impaired wound healing. In previous studies, we have demonstrated that ganglioside GM3 depletion by knockdown of GM3 synthase fully reverses impaired wound healing in diabetic mice. However, the role of GM3 in neuropathic pain and small fiber neuropathy in diabetes is unknown. Purpose Determine whether GM3 depletion is able to reverse neuropathic pain and small fibers neuropathy and the mechanism of the reversal. Results We demonstrate that GM3 synthase knockout and the resultant GM3 depletion rescues the denervation in mouse footpad skin and fully reverses the neuropathic pain in diet-induced obese diabetic mice. In cultured dorsal root ganglia from diet-induced diabetic mice, GM3 depletion protects against increased intracellular calcium influx in vitro. Conclusions These studies establish ganglioside GM3 as a new candidate responsible for neuropathic pain and small fiber neuropathy in diabetes. Moreover, these observations indicate that systemic or topically applied interventions aimed at depleting GM3 may improve both the painful neuropathy and the wound healing impairment in diabetes by protecting against nerve end terminal degeneration, providing a disease-modifying approach to this common, currently intractable medical issue. PMID:27590073

  7. Accumulation of GD1α Ganglioside in MDA-MB-231 Breast Cancer Cells Expressing ST6GalNAc V.

    PubMed

    Vandermeersch, Sandy; Vanbeselaere, Jorick; Delannoy, Clément P; Drolez, Aurore; Mysiorek, Caroline; Guérardel, Yann; Delannoy, Philippe; Julien, Sylvain

    2015-04-16

    α-Series gangliosides define a particular sub-class of glycosphingolipids containing sialic acid α2,6-linked to GalNAc residue that was isolated as a minor compound from the brain. The sialyltransferase ST6GalNAc V was cloned from mouse brain and showed α2,6-sialyltransferase activity almost exclusively for GM1b, to form GD1α and is considered as the main enzyme involved in the biosynthesis of α-series gangliosides. Recently, ST6GALNAC5 was identified as one of the genes over-expressed in breast cancer cell populations selected for their ability to produce brain metastasis. However, the capacity of human breast cancer cells to produce α-series gangliosides has never been clearly demonstrated. Here, we show by stable transfection and MS-MS analysis of total glycosphingolipids that ST6GALNAC5 expressing MDA-MB-231 breast cancer cells accumulate GD1α ganglioside (IV3Neu5Ac1, III6Neu5Ac1Gg4-Cer).

  8. Determination of the position of the 5d excited levels of Ce3+ ions with respect to the conduction band in the epitaxial films of the multicomponent (Lu,Gd)3(Ga,Al)5O12:Ce garnets

    NASA Astrophysics Data System (ADS)

    Babin, V.; Hanus, M.; Krasnikov, A.; Kučera, M.; Nikl, M.; Zazubovich, S.

    2016-12-01

    Temperature dependences of the intensity and decay kinetics of the Ce3+ - related photoluminescence and characteristics of thermally stimulated luminescence are investigated in the 77-500 K temperature range for the epitaxial films of the multicomponent garnets of the type of Lu3-xGdxGayAl5-yO12:Ce with Ce content of 0.3-0.7 at. %, where x varies from 0.14 to 3 and y varies from 0 to 3.54. Different methods are used for the determination of energy distances between the excited 5d1 and 5d2 levels of Ce3+ ions and the conduction band (CB) and their applicability is compared. The dependences of the 5d1,2 - CB energy distances on the multicomponent garnet composition are clarified. The 5d1 - CB energy distance is found to decrease by about an order of magnitude with the increasing Ga3+ content. The most drastic decrease, observed at the Ga3+ content around y ≈ 1.7, is suggested to arise from the change in the Ga3+ position from the smaller tetrahedral to larger octahedral Al3+ sites. This effect is explained by the lattice distortion due to the substitution of smaller Lu3+ and Al3+ ions by larger Gd3+ and Ga3+ ions. Application potential of these epitaxial films for fast 2D-imaging is discussed.

  9. Crystal growth, structural transitions, and magnetic properties of the fluorite-related osmates: Sm3OsO7, Eu3OsO7, and Gd3OsO7.

    PubMed

    Gemmill, William R; Smith, Mark D; Mozharivsky, Yurij A; Miller, Gordon J; zur Loye, Hans-Conrad

    2005-10-03

    The Ln3OsO7 (Ln = Sm, Eu, Gd) compounds were grown as single crystals from molten hydroxide fluxes. At temperatures above 235, 330, and 430 K, respectively, the Ln3OsO7 (Ln = Sm, Eu, Gd) compounds exist in the orthorhombic space group Cmcm. When they are cooled below these temperatures, the compounds undergo a structural phase transition from space group Cmcm to P2(1)nb. The structure transition results in a loss of lattice centering, a doubling of the b axis, a distortion of the vertex-shared Os-O chains, and a reduction in the coordination of one of the rare earth cations from 8-fold to 7-fold. Sm3OsO7 and Eu3OsO7 exhibit complex magnetic behavior below about 50 K, and Gd3OsO7 shows a ferromagnetic-like order at 34 K in applied fields of less than 10 kG.

  10. Structural and mutational analyses of the receptor binding domain of botulinum D/C mosaic neurotoxin: Insight into the ganglioside binding mechanism

    SciTech Connect

    Nuemket, Nipawan; Tanaka, Yoshikazu; Tsukamoto, Kentaro; Tsuji, Takao; Nakamura, Keiji; Kozaki, Shunji; Yao, Min; Tanaka, Isao

    2011-07-29

    Highlights: {yields} We determined the crystal structure of the receptor binding domain of BoNT in complex with 3'-sialyllactose. {yields} An electron density derived from the 3'-sialyllactose was confirmed at the cleft in the C-terminal subdomain. {yields} Alanine site-directed mutagenesis showed that GBS and GBL are important for ganglioside binding. {yields} A cell binding mechanism, which involves cooperative contribution of two sites, was proposed. -- Abstract: Clostridium botulinum type D strain OFD05, which produces the D/C mosaic neurotoxin, was isolated from cattle killed by the recent botulism outbreak in Japan. The D/C mosaic neurotoxin is the most toxic of the botulinum neurotoxins (BoNT) characterized to date. Here, we determined the crystal structure of the receptor binding domain of BoNT from strain OFD05 in complex with 3'-sialyllactose at a resolution of 3.0 A. In the structure, an electron density derived from the 3'-sialyllactose was confirmed at the cleft in the C-terminal subdomain. Alanine site-directed mutagenesis showed the significant contribution of the residues surrounding the cleft to ganglioside recognition. In addition, a loop adjoining the cleft also plays an important role in ganglioside recognition. In contrast, little effect was observed when the residues located around the surface previously identified as the protein receptor binding site in other BoNTs were substituted. The results of cell binding analysis of the mutants were significantly correlated with the ganglioside binding properties. Based on these observations, a cell binding mechanism of BoNT from strain OFD05 is proposed, which involves cooperative contribution of two ganglioside binding sites.

  11. Variants of BALB/c 3T3 cells lacking complex gangliosides retain a fibronectin matrix and spread normally on fibronectin-coated substrates

    PubMed Central

    1986-01-01

    Evidence has accumulated that di- and trisialogangliosides are involved in the interaction of cells with fibronectin. We have therefore tested the ability of variants of BALB/c 3T3 deficient in such gangliosides to organize a fibronectin matrix and to spread on fibronectin-coated substrates. Whereas BALB/c 3T3 cells contained gangliosides GM3, GM1, and GD1a, direct chemical analysis showed that five out of six variants isolated contained no detectable GD1a. By the overlaying of thin layer chromatograms of cellular gangliosides with 125I-cholera toxin, these variants were also found to lack ganglioside GM1. In contrast, the sialogalactoprotein profile of these cells, analyzed using an 125I- ricin/SDS polyacrylamide gel overlay technique, was similar to that of the parent cell line. All variants organized an extensive fibronectin matrix comparable to that of BALB/c 3T3, as shown using either immunofluorescence or lactoperoxidase-catalyzed iodination. The variants could also spread on fibronectin-coated substrates and adopt a morphology similar to that of BALB/c 3T3 cells, with little or no difference in the concentration of fibronectin required for 50% cell spreading. Cell spreading of the variants was accompanied by the formation of focal contacts and microfilament bundles, in a manner closely resembling that seen with BALB/c 3T3 cells. Treatment of BALB/c 3T3 cells with neuraminidase, which converts much of the cellular GD1a to GM1, did not affect cell spreading on fibronectin. The results clearly demonstrate that complex gangliosides are not essential for retention of a fibronectin matrix or for spreading on fibronectin- coated substrates. PMID:2935542

  12. A single site in human β-hexosaminidase A binds both 6-sulfate-groups on hexosamines and the sialic acid moiety of GM2 ganglioside

    PubMed Central

    Sharma, Rohita; Bukovac, Scott; Callahan, John; Mahuran, Don

    2010-01-01

    Human β-hexosaminidase A (Hex A) (αβ) is composed of two subunits whose primary structures are ~60% identical. Deficiency of either subunit results in severe neurological disease due to the storage of GM2 ganglioside; Tay–Sachs disease, α deficiency, and Sandhoff disease, β deficiency. Whereas both subunits contain active sites only the α-site can efficiently bind negatively charged 6-sulfated hexosamine substrates and GM2 ganglioside. We have recently identified the αArg424 as playing a critical role in the binding of 6-sulfate-containing substrates, and βAsp452 as actively inhibiting their binding. To determine if these same residues affect the binding of the sialic acid moiety of GM2 ganglioside, an αArg424Gln form of Hex A was expressed and its kinetics analyzed using the GM2 activator protein:[3H]-GM2 ganglioside complex as a substrate. The mutant showed a ~3-fold increase in its Km for the complex. Next a form of Hex B (ββ) containing a double mutation, βAspLeu453 AsnArg (duplicating the α-aligning sequences), was expressed. As compared to the wild type (WT), the mutant exhibited a >30-fold increase in its ability to hydrolyze a 6-sulfated substrate and was now able to hydrolyze GM2 ganglioside when the GM2 activator protein was replaced by sodium taurocholate. Thus, this α-site is critical for binding both types of negatively charge substrates. PMID:12527415

  13. Porcine Sapelovirus Uses α2,3-Linked Sialic Acid on GD1a Ganglioside as a Receptor

    PubMed Central

    Kim, Deok-Song; Son, Kyu-Yeol; Koo, Kyung-Min; Kim, Ji-Yun; Alfajaro, Mia Madel; Park, Jun-Gyu; Hosmillo, Myra; Soliman, Mahmoud; Baek, Yeong-Bin; Cho, Eun-Hyo; Lee, Ju-Hwan; Kang, Mun-Il

    2016-01-01

    ABSTRACT The receptor(s) for porcine sapelovirus (PSV), which causes diarrhea, pneumonia, polioencephalomyelitis, and reproductive disorders in pigs, remains largely unknown. Given the precedent for other picornaviruses which use terminal sialic acids (SAs) as receptors, we examined the role of SAs in PSV binding and infection. Using a variety of approaches, including treating cells with a carbohydrate-destroying chemical (NaIO4), mono- or oligosaccharides (N-acetylneuraminic acid, galactose, and 6′-sialyllactose), linkage-specific sialidases (neuraminidase and sialidase S), lectins (Maakia amurensis lectin and Sambucus nigra lectin), proteases (trypsin and chymotrypsin), and glucosylceramide synthase inhibitors (dl-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol and phospholipase C), we demonstrated that PSV could recognize α2,3-linked SA on glycolipids as a receptor. On the other hand, PSVs had no binding affinity for synthetic histo-blood group antigens (HBGAs), suggesting that PSVs could not use HBGAs as receptors. Depletion of cell surface glycolipids followed by reconstitution studies indicated that GD1a ganglioside, but not other gangliosides, could restore PSV binding and infection, further confirming α2,3-linked SA on GD1a as a PSV receptor. Our results could provide significant information on the understanding of the life cycle of sapelovirus and other picornaviruses. For the broader community in the area of pathogens and pathogenesis, these findings and insights could contribute to the development of affordable, useful, and efficient drugs for anti-sapelovirus therapy. IMPORTANCE The porcine sapelovirus (PSV) is known to cause enteritis, pneumonia, polioencephalomyelitis, and reproductive disorders in pigs. However, the receptor(s) that the PSV utilizes to enter host cells remains largely unknown. Using a variety of approaches, we showed that α2,3-linked terminal sialic acid (SA) on the cell surface GD1a ganglioside could be used for PSV

  14. Exogenous and Endogeneous Disialosyl Ganglioside GD1b Induces Apoptosis of MCF-7 Human Breast Cancer Cells

    PubMed Central

    Ha, Sun-Hyung; Lee, Ji-Min; Kwon, Kyung-Min; Kwak, Choong-Hwan; Abekura, Fukushi; Park, Jun-Young; Cho, Seung-Hak; Lee, Kichoon; Chang, Young-Chae; Lee, Young-Choon; Choi, Hee-Jung; Chung, Tae-Wook; Ha, Ki-Tae; Chang, Hyeun-Wook; Kim, Cheorl-Ho

    2016-01-01

    Gangliosides have been known to play a role in the regulation of apoptosis in cancer cells. This study has employed disialyl-ganglioside GD1b to apoptosis in human breast cancer MCF-7 cells using exogenous treatment of the cells with GD1b and endogenous expression of GD1b in MCF-7 cells. First, apoptosis in MCF-7 cells was observed after treatment of GD1b. Treatment of MCF-7 cells with GD1b reduced cell growth rates in a dose and time dependent manner during GD1b treatment, as determined by XTT assay. Among the various gangliosides, GD1b specifically induced apoptosis of the MCF-7 cells. Flow cytometry and immunofluorescence assays showed that GD1b specifically induces apoptosis in the MCF-7 cells with Annexin V binding for apoptotic actions in early stage and propidium iodide (PI) staining the nucleus of the MCF-7 cells. Treatment of MCF-7 cells with GD1b activated apoptotic molecules such as processed forms of caspase-8, -7 and PARP (Poly(ADP-ribose) polymerase), without any change in the expression of mitochondria-mediated apoptosis molecules such as Bax and Bcl-2. Second, to investigate the effect of endogenously produced GD1b on the regulation of cell function, UDP-gal: β1,3-galactosyltransferase-2 (GD1b synthase, Gal-T2) gene has been transfected into the MCF-7 cells. Using the GD1b synthase-transfectants, apoptosis-related signal proteins linked to phenotype changes were examined. Similar to the exogenous GD1b treatment, the cell growth of the GD1b synthase gene-transfectants was significantly suppressed compared with the vector-transfectant cell lines and transfection activated the apoptotic molecules such as processed forms of caspase-8, -7 and PARP, but not the levels of expression of Bax and Bcl-2. GD1b-induced apoptosis was blocked by caspase inhibitor, Z-VAD. Therefore, taken together, it was concluded that GD1b could play an important role in the regulation of breast cancer apoptosis. PMID:27144558

  15. Stability, water exchange, and anion binding studies on lanthanide(III) complexes with a macrocyclic ligand based on 1,7-diaza-12-crown-4: extremely fast water exchange on the Gd3+ complex.

    PubMed

    Pálinkás, Zoltán; Roca-Sabio, Adrián; Mato-Iglesias, Marta; Esteban-Gómez, David; Platas-Iglesias, Carlos; de Blas, Andrés; Rodríguez-Blas, Teresa; Tóth, Eva

    2009-09-21

    The picolinate-derivative ligand based on the 1,7-diaza-12-crown-4 platform (bp12c4(2-)) forms stable Ln(3+) complexes with stability constants increasing from the early to the middle lanthanides, then being relatively constant for the rest of the series (logK(LnL) = 16.81(0.06), 18.82(0.01), and 18.08(0.05) for Ln = La, Gd, and Yb, respectively). The complex formation is fast, allowing for direct potentiometric titrations to assess the stability constants. In the presence of Zn(2+), the dissociation of [Gd(bp12c4)](+) proceeds both via proton- and metal-assisted pathways, and in this respect, this system is intermediate between DTPA-type and macrocyclic, DOTA-type chelates, for which the dissociation is predominated by metal- or proton-assisted pathways, respectively. The Cu(2+) exchange shows an unexpected pH dependency, with the observed rate constants decreasing with increasing proton concentration. The rate of water exchange, assessed by (17)O NMR, is extremely high on the [Gd(bp12c4)(H(2)O)(q)](+) complex (k(ex)(298) = (2.20 +/- 0.15) x 10(8) s(-1)), and is in the same order of magnitude as for the Gd(3+) aqua ion (k(ex)(298) = 8.0 x 10(8) s(-1)). In aqueous solution, the [Gd(bp12c4)(H(2)O)(q)](+) complex is present in hydration equilibrium between nine-coordinate, monohydrated, and ten-coordinate, bishydrated species. We attribute the fast exchange to the hydration equilibrium and to the flexible nature of the inner coordination sphere. The large negative value of the activation entropy (DeltaS = -35 +/- 8 J mol(-1) K(-1)) points to an associative character for the water exchange and suggests that water exchange on the nine-coordinate, monohydrated species is predominant in the overall exchange. Relaxometric and luminescence measurements on the Gd(3+) and Eu(3+) analogues, respectively, indicate strong binding of endogenous anions such as citrate, hydrogencarbonate, or phosphate to [Ln(bp12c4)](+) complexes (K(aff) = 280 +/- 20 M(-1), 630 +/- 50 M(-1), and

  16. Ganglioside GM1 induces phosphorylation of mutant huntingtin and restores normal motor behavior in Huntington disease mice

    PubMed Central

    Di Pardo, Alba; Maglione, Vittorio; Alpaugh, Melanie; Horkey, Melanie; Atwal, Randy S.; Sassone, Jenny; Ciammola, Andrea; Steffan, Joan S.; Fouad, Karim; Truant, Ray; Sipione, Simonetta

    2012-01-01

    Huntington disease (HD) is a progressive neurodegenerative monogenic disorder caused by expansion of a polyglutamine stretch in the huntingtin (Htt) protein. Mutant huntingtin triggers neural dysfunction and death, mainly in the corpus striatum and cerebral cortex, resulting in pathognomonic motor symptoms, as well as cognitive and psychiatric decline. Currently, there is no effective treatment for HD. We report that intraventricular infusion of ganglioside GM1 induces phosphorylation of mutant huntingtin at specific serine amino acid residues that attenuate huntingtin toxicity, and restores normal motor function in already symptomatic HD mice. Thus, our studies have identified a potential therapy for HD that targets a posttranslational modification of mutant huntingtin with critical effects on disease pathogenesis. PMID:22331905

  17. Molecular recognition and colorimetric detection of cholera toxin by poly(diacetylene) liposomes incorporating G{sub m1} ganglioside

    SciTech Connect

    Pan, J.J.; Charych, D.

    1997-03-19

    Molecular recognition sites on cell membranes serve as the main communication channels between the inside of a cell and its surroundings. Upon receptor binding, cellular messages such as ion channel opening or activation of enzymes are triggered. In this report, we demonstrate that artificial cell membranes made from conjugated lipid polymers (poly(diacetylene)) can, on a simple level, mimic membrane processes of molecular recognition and signal transduction. The ganglioside GM1 was incorporated into poly(diacetylene) liposomes. Molecular recognition of cholera toxin at the interface of the liposome resulted in a change of the membrane color due to conformational charges in the conjugated (ene-yne) polymer backbone. The `colored liposomes` might be used as simple colorimetric sensors for drug screening or as new tools to study membrane-membrane or membrane-receptor interactions. 21 refs., 3 figs.

  18. Sphingolipids: Key Regulators of Apoptosis and Pivotal Players in Cancer Drug Resistance

    PubMed Central

    Giussani, Paola; Tringali, Cristina; Riboni, Laura; Viani, Paola; Venerando, Bruno

    2014-01-01

    Drug resistance elicited by cancer cells still constitutes a huge problem that frequently impairs the efficacy of both conventional and novel molecular therapies. Chemotherapy usually acts to induce apoptosis in cancer cells; therefore, the investigation of apoptosis control and of the mechanisms used by cancer cells to evade apoptosis could be translated in an improvement of therapies. Among many tools acquired by cancer cells to this end, the de-regulated synthesis and metabolism of sphingolipids have been well documented. Sphingolipids are known to play many structural and signalling roles in cells, as they are involved in the control of growth, survival, adhesion, and motility. In particular, in order to increase survival, cancer cells: (a) counteract the accumulation of ceramide that is endowed with pro-apoptotic potential and is induced by many drugs; (b) increase the synthesis of sphingosine-1-phosphate and glucosylceramide that are pro-survivals signals; (c) modify the synthesis and the metabolism of complex glycosphingolipids, particularly increasing the levels of modified species of gangliosides such as 9-O acetylated GD3 (αNeu5Ac(2-8)αNeu5Ac(2-3)βGal(1-4)βGlc(1-1)Cer) or N-glycolyl GM3 (αNeu5Ac (2-3)βGal(1-4)βGlc(1-1)Cer) and de-N-acetyl GM3 (NeuNH(2)βGal(1-4)βGlc(1-1)Cer) endowed with anti-apoptotic roles and of globoside Gb3 related to a higher expression of the multidrug resistance gene MDR1. In light of this evidence, the employment of chemical or genetic approaches specifically targeting sphingolipid dysregulations appears a promising tool for the improvement of current chemotherapy efficacy. PMID:24625663

  19. Microstructure evolution and mechanical properties of a large-sized ingot of Mg-9Gd-3Y-1.5Zn-0.5Zr (wt%) alloy after a lower-temperature homogenization treatment

    NASA Astrophysics Data System (ADS)

    Xue, Zhi-yong; Ren, Yue-juan; Luo, Wen-bo; Ren, Yu; Xu, Ping; Xu, Chao

    2017-03-01

    In this paper, a large-sized ingot of Mg-9Gd-3Y-1.5Zn-0.5Zr (wt%) alloy with a diameter of 600 mm was successfully prepared by the semi-continuous casting method. The alloy was subsequently annealed at a relatively low temperature of 430°C for 12 h as a homogenization treatment. The microstructure and room-temperature mechanical properties of the alloy were investigated systematically. The results show that the as-cast alloy contained a mass of discontinuous lamellar-shaped 18R long-period stacking ordered (LPSO) phases with a composition of Mg10ZnY and an α-Mg matrix, along with net-shaped Mg5(Y,Gd) eutectic compounds at the grain boundaries. Most of the eutectic compounds dissolved after the homogenization treatment. Moreover, the amount and dimensions of the lamellar-shaped LPSO phase obviously increased after the homogenization treatment. The structure of the phase transformed into 14H-type LPSO with composition Mg12Zn(Y,Gd). The mechanical properties of the heat-treated large-sized alloy ingot are uniform. The ultimate tensile strength (UTS) and tensile yield strength (TYS) of the alloy reached 207.2 MPa and 134.8 MPa, respectively, and the elongation was 3.4%. The high performances of the large-sized alloy ingot after the homogenization treatment is attributed to the strengthening of the α-Mg solid solution and to the plentiful LPSO phase distributed over the α-Mg matrix.

  20. Distribution of ganglioside GM1 in L-alpha-dipalmitoylphosphatidylcholine/cholesterol monolayers: a model for lipid rafts.

    PubMed Central

    Yuan, C; Johnston, L J

    2000-01-01

    The distribution of low concentrations of ganglioside GM1 in L-alpha-dipalmitoylphosphatidylcholine (DPPC) and DPPC/cholesterol monolayers supported on mica has been studied using atomic force microscopy (AFM). The monolayers studied correspond to a pure gel phase and a mixture of liquid-expanded (LE) and liquid-condensed (LC) phases for DPPC and to a single homogeneous liquid-ordered phase for 2:1 DPPC/cholesterol. The addition of 2.5-5% GM1 to phase-separated DPPC monolayers resulted in small round ganglioside-rich microdomains in the center and at the edges of the LC domains. Higher amounts of GM1 (10%) give numerous filaments in the center of the LC domains and larger patches at the edges. A gel phase DPPC monolayer containing GM1 showed large domains containing a network of GM1-rich filaments. The addition of GM1 to a liquid-ordered 2:1 DPPC/cholesterol monolayer gives small, round domains that vary in size from 50 to 150 nm for a range of surface pressures. Larger amounts of GM1 lead to coalescence of the small, round domains to give longer filaments that cover 30-40% of the monolayer surface for 10 mol % GM1. The results indicate that biologically relevant GM1 concentrations lead to submicron-sized domains in a cholesterol-rich liquid-ordered phase that is analogous to that found in detergent-insoluble membrane fractions, and are thought to be important in membrane microdomains or rafts. This demonstrates that AFM studies of model monolayers and bilayers provide a powerful method for the direct detection of microdomains that are too small for study with most other techniques. PMID:11053150

  1. Bovine complex milk lipid containing gangliosides for prevention of rotavirus infection and diarrhoea in northern Indian infants.

    PubMed

    Poppitt, Sally D; McGregor, Robin A; Wiessing, Katy R; Goyal, Vimal K; Chitkara, Amar J; Gupta, Sarika; Palmano, Kate; Kuhn-Sherlock, Barbara; McConnell, Michelle A

    2014-08-01

    Rotavirus (RV) is a leading cause of morbidity and mortality in children younger than 5 years of age, presenting commonly with diarrhoeal symptoms. In a prospective 12-week double-blind randomised controlled trial we assessed acceptability and efficacy of a high-ganglioside complex milk lipid (CML) for prevention of RV infection in 450 infants, ages 8 to 24 months, at 3 sites in northern India. Prevalence of diarrhoea and RV was unseasonably low at baseline (all-cause diarrhoea [ACD], n = 16; RV diarrhoea [RVD], n = 2; RV infection, RV positive [RV+], n = 20) and throughout the trial, with only 110 total episodes of ACD for 12 weeks (CML, n = 62; control, n = 48) of which 10 were RVD (CML, n = 4; control, n = 6). Mean duration that RVD persisted was lower in the CML group (2.3 ± 0.5 days) than that in the control group (3.8 ± 1.3 days, P = 0.03), but only 3 of 450 end of trial stool samples were identified as RV+ (<1%; CML, n = 2; control, n = 1). This hampered the assessment of efficacy of CML, despite the large a priori determined sample size. During the trial similar numbers of infants reported adverse events (AEs: CML 41%, control 46%), with the majority of events classified as mild and not related to the intervention. In conclusion, further clinical trials against a higher background of seasonal prevalence are necessary to assess efficacy of this nutritional intervention to prevent RVD. More important, however, high-ganglioside CML was acceptable for long-term consumption in infants ages 8 to 24 months.

  2. Sialidase NEU3 contributes neoplastic potential on colon cancer cells as a key modulator of gangliosides by regulating Wnt signaling.

    PubMed

    Takahashi, Kohta; Hosono, Masahiro; Sato, Ikuro; Hata, Keiko; Wada, Tadashi; Yamaguchi, Kazunori; Nitta, Kazuo; Shima, Hiroshi; Miyagi, Taeko

    2015-10-01

    The plasma membrane-associated sialidase NEU3 is a key enzyme for ganglioside degradation. We previously demonstrated remarkable up-regulation of NEU3 in various human cancers, with augmented malignant properties. Here, we provide evidence of a close link between NEU3 expression and Wnt/β-catenin signaling in colon cancer cells by analyzing tumorigenic potential and cancer stem-like characteristics. NEU3 silencing in HT-29 and HCT116 colon cancer cells resulted in significant decrease in clonogenicity on soft agar and in vivo tumor growth, along with down-regulation of stemness and Wnt-related genes. Analyses further revealed that NEU3 enhanced phosphorylation of the Wnt receptor LRP6 and consequently β-catenin activation by accelerating complex formation with LRP6 and recruitment of GSK3β and Axin, whereas its silencing exerted the opposite effects. NEU3 activity-null mutants failed to demonstrate the activation, indicating the requirement of ganglioside modulation by the sialidase for the effects. Under sphere-forming conditions, when stemness genes are up-regulated, endogenous NEU3 expression was found to be significantly increased, whereas NEU3 silencing suppressed sphere-formation and in vivo tumor incidence in NOD-SCID mice. Increased ability of clonogenicity on soft agar and sphere formation by Wnt stimulation was abrogated by NEU3 silencing. Furthermore, NEU3 was found to regulate phosphorylation of ERK and Akt via EGF receptor and Ras cascades, thought to be additionally required for tumor progression. The results indicate an essential contribution of NEU3 to tumorigenic potential through maintenance of stem-like characteristics of colon cancer cells by regulating Wnt signaling at the receptor level, in addition to tumor progression via Ras/MAPK signaling.

  3. NEU3 inhibitory effect of naringin suppresses cancer cell growth by attenuation of EGFR signaling through GM3 ganglioside accumulation.

    PubMed

    Yoshinaga, Ayana; Kajiya, Natsuki; Oishi, Kazuki; Kamada, Yuko; Ikeda, Asami; Chigwechokha, Petros Kingstone; Kibe, Toshiro; Kishida, Michiko; Kishida, Shosei; Komatsu, Masaharu; Shiozaki, Kazuhiro

    2016-07-05

    Naringin, which is one of the flavonoids contained in citrus fruits, is well known to possess various healthy functions to humans. It has been reported that naringin suppresses cancer cell growth in vitro and in vivo, although the underlying mechanisms are not fully understood. Recently, the roles of glycoconjugates, such as gangliosides, in cancer cells have been focused because of their regulatory effects of malignant phenotypes. Here, to clarify the roles of naringin in the negative-regulation of cancer cell growth, the alteration of glycoconjugates induced by naringin exposure and its significance on cell signaling were investigated. Human cancer cells, HeLa and A549, were exposed to various concentrations of naringin. Naringin treatment induced the suppression of cell growth toward HeLa and A549 cells accompanied with an increase of apoptotic cells. In naringin-exposed cells, GM3 ganglioside was drastically increased compared to the GM3 content prior to the treatment. Furthermore, naringin inhibited NEU3 sialidase, a GM3 degrading glycosidase. Similarly, NEU3 inhibition activities were also detected by other flavanone, such as hesperidin and neohesperidin dihydrocalcone, but their aglycones showed less inhibitions. Naringin-treated cancer cells showed suppressed EGFR and ERK phosphorylation levels. These results suggest a novel mechanism of naringin in the suppression of cancer cell growth through the alteration of glycolipids. NEU3 inhibitory effect of naringin induced GM3 accumulation in HeLa and A549 cells, leading the attenuation of EGFR/ERK signaling accompanied with a decrease in cell growth.

  4. Effects of ganglioside G(M1) and erythropoietin on spinal cord lesions in rats: functional and histological evaluations

    PubMed Central

    Marcon, Raphael Martus; Cristante, Alexandre Fogaça; de Barros Filho, Tarcísio Eloy Pessoa; Ferreira, Ricardo; dos Santos, Gustavo Bispo

    2016-01-01

    OBJECTIVE: To evaluate the functional and histological effects of ganglioside G(M1) and erythropoietin after experimental spinal cord contusion injury. METHODS: Fifty male Wistar rats underwent experimental spinal cord lesioning using an NYU-Impactor device and were randomly divided into the following groups, which received treatment intraperitoneally. The G(M1) group received ganglioside G(M1) (30 mg/kg); the erythropoietin group received erythropoietin (1000 IU/kg); the combined group received both drugs; and the saline group received saline (0.9%) as a control. A fifth group was the laminectomy group, in which the animals were subjected to laminectomy alone, without spinal lesioning or treatment. The animals were evaluated according to the Basso, Beattie and Bresnahan (BBB) scale, motor evoked potential recordings and, after euthanasia, histological analysis of spinal cord tissue. RESULTS: The erythropoietin group had higher BBB scores than the G(M1) group. The combined group had the highest BBB scores, and the saline group had the lowest BBB scores. No significant difference in latency was observed between the three groups that underwent spinal cord lesioning and intervention. However, the combined group showed a significantly higher signal amplitude than the other treatment groups or the saline group (p<0.01). Histological tissue analysis showed no significant difference between the groups. Axonal index was significantly enhanced in the combined group than any other intervention (p<0.01). CONCLUSION: G(M1) and erythropoietin exert therapeutic effects on axonal regeneration and electrophysiological and motor functions in rats subjected to experimental spinal cord lesioning and administering these two substances in combination potentiates their effects. PMID:27438570

  5. Restoration of the GM2 ganglioside metabolism in bone marrow-derived stromal cells from Tay-Sachs disease animal model.

    PubMed

    Martino, S; Cavalieri, C; Emiliani, C; Dolcetta, D; Cusella De Angelis, M G; Chigorno, V; Severini, G M; Sandhoff, K; Bordignon, C; Sonnino, S; Orlacchio, A

    2002-08-01

    The therapeutic potential of bone marrow-derived stromal cells for the therapy of Tay-Sachs disease is primarily related to the restoration of their own GM2 ganglioside storage. With this aim, we produced bone marrow-derived stromal cells from the adult Tay-Sachs animal model and transduced them with a retroviral vector encoding for the alpha-subunit of the lysosomal enzyme beta-hexosaminidase A (E.C. 3.2.1.52). Our results demonstrate that transduced Tay-Sachs bone marrow-derived stromal cells have beta-hexosaminidase A comparable to that of bone marrow-derived stromal cells from wild-type mice. Moreover, beta-hexosaminidase A in transduced Tay-Sachs bone marrow-derived stromal cells was able to hydrolyze the GM2 ganglioside in a feeding experiment, thus demonstrating the correction of the altered phenotype.

  6. Delineation and comparison of ganglioside-binding epitopes for the toxins of Vibrio cholerae, Escherichia coli, and Clostridium tetani: evidence for overlapping epitopes.

    PubMed

    Angström, J; Teneberg, S; Karlsson, K A

    1994-12-06

    Binding studies of various glycolipids, mainly belonging to the ganglio series, to the toxins isolated from Vibrio cholerae, Escherichia coli, and Clostridium tetani have been performed, using the microtiter well assay. By using the found binding preferences in conjunction with minimum-energy conformations obtained from molecular modeling of the various ligands, binding epitopes on the natural receptor glycolipids for the toxins have been defined. The binding preferences for the cholera toxin and the heat-labile E. coli toxin are very similar, with the ganglioside GM1 being the most efficient ligand. The tetanus toxin binds strongly to gangliosides of the G1b series, with GT1b as the most efficient ligand. It is found that the binding epitope on GM1 for the cholera and heat-labile toxins to a large extent overlaps with the epitope on GQ1b for the tetanus toxin.

  7. Clostridium botulinum type C hemagglutinin affects the morphology and viability of cultured mammalian cells via binding to the ganglioside GM3.

    PubMed

    Sugawara, Yo; Iwamori, Masao; Matsumura, Takuhiro; Yutani, Masahiro; Amatsu, Sho; Fujinaga, Yukako

    2015-09-01

    Botulinum neurotoxin is conventionally divided into seven serotypes, designated A-G, and is produced as large protein complexes through associations with non-toxic components, such as hemagglutinin (HA) and non-toxic non-HA. These non-toxic proteins dramatically enhance the oral toxicity of the toxin complex. HA is considered to have a role in toxin transport through the intestinal epithelium by carbohydrate binding and epithelial barrier-disrupting activity. Type A and B HAs disrupt E-cadherin-mediated cell adhesion, and, in turn, the intercellular epithelial barrier. Type C HA (HA/C) disrupts the barrier function by affecting cell morphology and viability, the mechanism of which remains unknown. In this study, we identified GM3 as the target molecule of HA/C. We found that sialic acid binding of HA is essential for the activity. It was abolished when cells were pre-treated with an inhibitor of ganglioside synthesis. Consistent with this, HA/C bound to a-series gangliosides in a glycan array. In parallel, we isolated clones resistant to HA/C activity from a susceptible mouse fibroblast strain. These cells lacked expression of ST-I, the enzyme that transfers sialic acid to lactosylceramide to yield GM3. These clones became sensitive to HA/C activity when GM3 was expressed by transfection with the ST-I gene. The sensitivity of fibroblasts to HA/C was reduced by expressing ganglioside synthesis genes whose products utilize GM3 as a substrate and consequently generate other a-series gangliosides, suggesting a GM3-specific mechanism. Our results demonstrate that HA/C affects cells in a GM3-dependent manner.

  8. Increased Expression of Simple Ganglioside Species GM2 and GM3 Detected by MALDI Imaging Mass Spectrometry in a Combined Rat Model of Aβ Toxicity and Stroke

    PubMed Central

    Caughlin, Sarah; Hepburn, Jeffrey D.; Park, Dae Hee; Jurcic, Kristina; Yeung, Ken K.-C.; Cechetto, David F.; Whitehead, Shawn N.

    2015-01-01

    The aging brain is often characterized by the presence of multiple comorbidities resulting in synergistic damaging effects in the brain as demonstrated through the interaction of Alzheimer’s disease (AD) and stroke. Gangliosides, a family of membrane lipids enriched in the central nervous system, may have a mechanistic role in mediating the brain’s response to injury as their expression is altered in a number of disease and injury states. Matrix-Assisted Laser Desorption Ionization (MALDI) Imaging Mass Spectrometry (IMS) was used to study the expression of A-series ganglioside species GD1a, GM1, GM2, and GM3 to determine alteration of their expression profiles in the presence of beta-amyloid (Aβ) toxicity in addition to ischemic injury. To model a stroke, rats received a unilateral striatal injection of endothelin-1 (ET-1) (stroke alone group). To model Aβ toxicity, rats received intracerebralventricular (icv) injections of the toxic 25-35 fragment of the Aβ peptide (Aβ alone group). To model the combination of Aβ toxicity with stroke, rats received both the unilateral ET-1 injection and the bilateral icv injections of Aβ₂₅₋₃₅ (combined Aβ/ET-1 group). By 3 d, a significant increase in the simple ganglioside species GM2 was observed in the ischemic brain region of rats who received a stroke (ET-1), with or without Aβ. By 21 d, GM2 levels only remained elevated in the combined Aβ/ET-1 group. GM3 levels however demonstrated a different pattern of expression. By 3 d GM3 was elevated in the ischemic brain region only in the combined Aβ/ET-1 group. By 21 d, GM3 was elevated in the ischemic brain region in both stroke alone and Aβ/ET-1 groups. Overall, results indicate that the accumulation of simple ganglioside species GM2 and GM3 may be indicative of a mechanism of interaction between AD and stroke. PMID:26086081

  9. Tissue Reactivity of the 14F7 Mab Raised against N-Glycolyl GM3 Ganglioside in Tumors of Neuroectodermal, Mesodermal, and Epithelial Origin

    PubMed Central

    Blanco, Rancés; Quintana, Yisel; Blanco, Damián; Cedeño, Mercedes; Rengifo, Charles E.; Frómeta, Milagros; Ríos, Martha; Rengifo, Enrique; Carr, Adriana

    2013-01-01

    The expression of N-glycolylneuraminic acid forming the structure of gangliosides and/or other glycoconjugates (Hanganutziu-Deicher antigen) in human has been considered as a tumor-associated antigen. Specifically, some reports of 14F7 Mab (a highly specific Mab raised against N-glycolyl GM3 ganglioside) reactivity in human tumors have been recently published. Nevertheless, tumors of epithelial origin have been mostly evaluated. The goal of the present paper was to evaluate the immunohistochemical recognition of 14F7 Mab in different human tumors of neuroectodermal, mesodermal, and epithelial origins using an immunoperoxidase staining method. Samples of fetal, normal, and reactive astrocytosis of the brain were also included in the study. In general, nontumoral tissues, as well as, low-grade brain tumors showed no or a limited immunoreaction with 14F7 Mab. Nevertheless, high-grade astrocytomas (III-IV) and neuroblastomas, as well as, sarcomas and thyroid carcinomas were mostly reactive with 14F7. No reaction was evidenced in medulloblastomas and ependymoblastomas. Our data suggest that the expression of N-glycolyl GM3 ganglioside could be related to the aggressive behavior of malignant cells, without depending on the tumor origin. Our data could also support the possible use of N-glycolyl GM3 as a target for both active and passive immunotherapies of malignancies expressing this molecule. PMID:26317019

  10. Tissue Reactivity of the 14F7 Mab Raised against N-Glycolyl GM3 Ganglioside in Tumors of Neuroectodermal, Mesodermal, and Epithelial Origin.

    PubMed

    Blanco, Rancés; Quintana, Yisel; Blanco, Damián; Cedeño, Mercedes; Rengifo, Charles E; Frómeta, Milagros; Ríos, Martha; Rengifo, Enrique; Carr, Adriana

    2013-01-01

    The expression of N-glycolylneuraminic acid forming the structure of gangliosides and/or other glycoconjugates (Hanganutziu-Deicher antigen) in human has been considered as a tumor-associated antigen. Specifically, some reports of 14F7 Mab (a highly specific Mab raised against N-glycolyl GM3 ganglioside) reactivity in human tumors have been recently published. Nevertheless, tumors of epithelial origin have been mostly evaluated. The goal of the present paper was to evaluate the immunohistochemical recognition of 14F7 Mab in different human tumors of neuroectodermal, mesodermal, and epithelial origins using an immunoperoxidase staining method. Samples of fetal, normal, and reactive astrocytosis of the brain were also included in the study. In general, nontumoral tissues, as well as, low-grade brain tumors showed no or a limited immunoreaction with 14F7 Mab. Nevertheless, high-grade astrocytomas (III-IV) and neuroblastomas, as well as, sarcomas and thyroid carcinomas were mostly reactive with 14F7. No reaction was evidenced in medulloblastomas and ependymoblastomas. Our data suggest that the expression of N-glycolyl GM3 ganglioside could be related to the aggressive behavior of malignant cells, without depending on the tumor origin. Our data could also support the possible use of N-glycolyl GM3 as a target for both active and passive immunotherapies of malignancies expressing this molecule.

  11. Stimulation of a Ca sup 2+ -dependent protein kinase by G sub M1 ganglioside in nerve growth factor-treated PC12 cells

    SciTech Connect

    Hilbush, B.S.; Levine, J.M. )

    1991-07-01

    The authors have investigated the ability of exogenous gangliosides to modulate nerve growth factor (NGF) signal transduction in PC12 cells. The effects of exogenous ganglioside G{sub M1} on multiple protein kinase activities were assayed by analyzing site-specific serine phosphorylation of tyrosine hydroxylase (TyrOHase) by two-dimensional phosphopeptide mapping. In the presence of NGF, exogenous G{sub M1} increased {sup 32}P incorporation into TyrOHase phosphopeptide T2, a Ca{sup 2+}/calmodulin-dependent protein kinase substrate whose phosphorylation is not normally affected by NGF treatment. In the absence of NGF, G{sub M1} treatment had no significant effects on TyrOHase phosphorylation. The removal of extracellular Ca{sup 2+} or blockade of dihydropyridine-sensitive Ca{sup 2+} channels prevented the G{sub M1}-induced increases in {sup 32}P incorporation into phosphopeptide T2. Exogenous G{sub M1} also potentiated K{sup +} depolarization-induced increases in the phosphorylation of TyrOHase. These results suggest that the stimulatory effects of exogenous G{sub M1} ganglioside on NGF actions may be due to its ability to potentiate a Ca{sup 2+}-dependent signaling pathway.

  12. Effect of ganglioside GT1b on the in vitro maturation of porcine oocytes and embryonic development

    PubMed Central

    HWANG, Seon-Ung; JEON, Yubyeol; YOON, Junchul David; CAI, Lian; KIM, Eunhye; YOO, Hyunju; KIM, Kyu-Jun; PARK, Kyu Mi; JIN, Minghui; KIM, Hyunggee; HYUN, Sang-Hwan

    2015-01-01

    Ganglioside is an acidic glycosphingolipid with sialic acids residues. This study was performed to investigate the effect and mechanism of ganglioside GT1b in porcine oocytes in the process of in vitro maturation (IVM) and preimplantation development. Metaphase II (MII) rates were significantly (P < 0.05) different between the control group and the 5 nM GT1b treatment group. Intracellular glutathione (GSH) levels in oocytes matured with 5 nM and 20 nM and GT1b decreased significantly (P < 0.05). The 10 nM group showed a significant (P < 0.05) decrease in intracellular reactive oxygen species (ROS) levels compared with the control group. Subsequently, the level of intracellular Ca2+ in oocytes treated with different concentrations of GT1b was measured. Intracellular Ca2+ was significantly (P < 0.05) increased with a higher concentration of GT1b in a dose-dependent manner. Real-time PCR was performed and showed that the expression of bradykinin 2 receptor (B2R) and calcium/calmodulin-dependent protein kinase II delta (CaMKIIδ) in cumulus cells was significantly (P < 0.05) decreased in the 20 nM GT1b treatment group. Treatment with 5 nM GT1b significantly (P < 0.05) decreased the expression of CaMKIIδ. In oocytes, treatment with 5 nM GT1b significantly (P < 0.05) decreased CaMKIIγ and POU5F1 (POU domain, class 5, transcription factor 1). However, treatment with 20 nM GT1b significantly (P < 0.05) increased the expression of POU5F1. Finally, embryonic developmental data showed no significant differences in the two experiments (parthenogenesis and in vitro fertilization). In conclusion, the results of the present study indicated that GT1b plays an important role in increasing the nuclear maturation rate and decreasing the intracellular ROS levels during IVM. However, GT1b inhibited maturation of the cytoplasm by maintaining intracellular Ca2+ in the process of oocyte maturation regardless of the cell cycle stage. Therefore, GT1b is thought to act on another mechanism

  13. Analysis and optimization of interactions between peptides mimicking the GD2 ganglioside and the monoclonal antibody 14G2a.

    PubMed

    Horwacik, Irena; Kurciński, Mateusz; Bzowska, Małgorzata; Kowalczyk, Aleksandra K; Czaplicki, Dominik; Koliński, Andrzej; Rokita, Hanna

    2011-07-01

    Overexpression of the GD2 ganglioside (GD2) is a hallmark of neuroblastoma. The antigen is used in neuroblastoma diagnosis and to target newly developed therapies to cancer cells. Peptide mimetics are novel approaches in the design of antigens for vaccine development. We previously reported the isolation of five GD2-mimicking peptides from the LX-8 phage display library with the monoclonal antibody (mAb) 14G2a. The goal of our current study was to analyze and optimize the binding of the peptide mimetics to the mAb 14G2a. Therefore, we performed further experiments and supported them with molecular modeling to investigate structure-activity relationships that are the basis for the observed mimicry of GD2 by our peptides. Here, we show that the peptides have overlapping binding sites on the mAb, 14G2a and restricted specificity, as they did not crossreact with other ganglioside-specific antibodies tested. In addition we demonstrate that the phage environment was involved in the process of selection of our peptides. The AAEGD sequence taken from the viral major coat protein, p8, and added to the C-termini of the peptides #65, #85 and #94 significantly improved their binding to the mAb, 14G2a. By application of analogs with amino acid substitutions and sequence truncations, we elucidated the structure-activity relationships necessary for the interactions between the 14G2a mAb and the peptide #94 (RCNPNMEPPRCF). We identified amino acids indispensable for the observed GD2-mimicry by #94 and confirmed a pivotal role of the disulphide bridge between the cysteine residues of #94 for binding to the mAb 14G2a. More importantly, we report five new peptides demonstrating a significant improvement of mAb 14G2a binding. The experimental data were supported and expanded with molecular modeling tools. Taken together, the experimental results and the in silico data allowed us to probe in detail the mechanism of the molecular mimicry of GD2 by the peptides. Additionally, we

  14. Epidermal growth factor-induced mobilization of a ganglioside-specific sialidase (NEU3) to membrane ruffles

    SciTech Connect

    Yamaguchi, Kazunori; Hata, Keiko; Wada, Tadashi; Moriya, Setsuko; Miyagi, Taeko . E-mail: miyagi-ta173@pref.miyagi.jp

    2006-07-28

    Human ganglioside-specific sialidase, NEU3, localized at cell membranes is thought to regulate various biological processes at cell surfaces. We here explored functional subcellular localization of the sialidase by immunofluorescence and found accumulation at leading edges of cell membranes in the presence of serum in culture. In response to EGF, the sialidase redistributed rapidly to ruffling cell membranes of squamous carcinoma A431 cells and co-localized with Rac-1. NEU3 overexpression enhanced Rac-1 activation and cell migration as compared with controls in HeLa cells as well as in A431 cells. Consistent with co-localization with Rac-1 by immunofluorescence, NEU3 was found to co-precipitate with activated Rac bound to GST-PAK-1 fusion protein. NEU3 silencing by siRNA, in contrast, resulted in inhibition of Rac-1 activation. These results indicate that NEU3 is able to mobilize to membrane ruffles in response to growth stimuli and activate the Rac-1 signaling by co-localization with Rac-1, leading to increased cell motility.

  15. Interaction between ganglioside G(M1) and diosgenin in langmuir monolayers at the air/water interface.

    PubMed

    Hao, Changchun; Zhang, Lei; Sun, Runguang; Yang, Jing; He, Guangxiao

    2014-01-01

    The interaction between ganglioside GM1 (GM1) and diosgenin (Dios) in mixed monolayers was investigated using surface pressure measurements and atomic force microscopy (AFM). The miscibility and stability of the mixed monolayer was evaluated both in a qualitative and quantitative way in terms of the excess mean molecular area (ΔAex), excess Gibbs energy (ΔGex). The ΔAex of mixed GM1/Dios monolayer was found to have positive deviations from ideality at low Dios mole fractions (XDios = 0.2). Above XDios = 0.2, there was a marked negative deviation from ideal mixing, indicating attractive interaction between G(M1) and Dios. According to the values of excess Gibbs energy of mixing monolayers, the more stable monolayers assayed was: XDios = 0.6. The compressibility coefficient was assessed at various surface pressures. The monolayer of Dios was more elasticity or rigid than G(M1). The AFM images for the mixed monolayers at 30 mN/m indicated there was obvious phase separation in the mixed monolayers. These findings will provide useful information for understanding the interaction between drug and lipids.

  16. Preparation of Alexa Fluor 350-conjugated nonradioactive or 3H-labeled GM1 ganglioside derivatives with different ceramides.

    PubMed

    Panasiewicz, Mirosława; Domek, Hanna; Fedoryszak, Natalia; Pacuszka, Tadeusz

    2009-02-01

    Alexa Fluor 350 hydrazide (AF) was coupled to the aldehyde group at C-6 of terminal galactose of oxidized GM1 gangliosides containing different fatty acid residues (GM1s). The AF-GM1 hydrazones obtained were reduced with NaBH(4) or [3H]NaBH(4) and purified by high-performance thin layer chromatography (HPTLC) and high-performance liquid chromatography (HPLC). Final yields of AF-GM1s exceeded 30%, purity was better than 97%, and radiochemical purity of 3H-labeled AF-GM1s was more than 94.5%. Structures of AF-GM1s were confirmed by electrospray ionization-mass spectrometry (ESI-MS). When added to HL-60 cell culture media, more than 81.6 or 78.9% of the AF-[3H]GM1s were taken up by cells in a bovine serum albumin- or trypsin-resistant manner, respectively. Approximately 70% of the AF-[3H]GM1s were recovered in HL-60 total plasma membrane fraction.

  17. Method for lipidomic analysis: p53 expression modulation of sulfatide, ganglioside, and phospholipid composition of U87 MG glioblastoma cells.

    PubMed

    He, Huan; Conrad, Charles A; Nilsson, Carol L; Ji, Yongjie; Schaub, Tanner M; Marshall, Alan G; Emmett, Mark R

    2007-11-15

    Lipidomics can complement genomics and proteomics by providing new insight into dynamic changes in biomembranes; however, few reports in the literature have explored, on an organism-wide scale, the functional link between nonenzymatic proteins and cellular lipids. Here, we report changes induced by adenovirus-delivered wild-type p53 gene and chemotherapy of U87 MG glioblastoma cells, a treatment known to trigger apoptosis and cell cycle arrest. We compare polar lipid changes in treated cells and control cells by use of a novel, sensitive method that employs lipid extraction, one-step liquid chromatography separation, high-resolution mass analysis, and Kendrick mass defect analysis. Nano-LC FT-ICR MS and quadrupole linear ion trap MS/MS analysis of polar lipids yields hundreds of unique assignments of glyco- and phospholipids at sub-ppm mass accuracy and high resolving power (m/Deltam50% = 200 000 at m/z 400) at 1 s/scan. MS/MS data confirm molecular structures in many instances. Sulfatides are most highly modulated by wild-type p53 treatment. The treatment also leads to an increase in phospholipids such as phosphatidyl inositols, phosphatidyl serines, phosphatidyl glycerols, and phosphatidyl ethanolamines. An increase in hydroxylated phospholipids is especially noteworthy. Also, a decrease in the longer chain gangliosides, GD1 and GM1b, is observed in wild-type p53 (treated) cells.

  18. Structure-Activity Relationship Study of the Neuritogenic Potential of the Glycan of Starfish Ganglioside LLG-3 ‡

    PubMed Central

    Yamagishi, Megumi; Hosoda-Yabe, Ritsuko; Tamai, Hideki; Konishi, Miku; Imamura, Akihiro; Ishida, Hideharu; Yabe, Tomio; Ando, Hiromune; Kiso, Makoto

    2015-01-01

    LLG-3 is a ganglioside isolated from the starfish Linchia laevigata. To clarify the structure-activity relationship of the glycan of LLG-3 toward rat pheochromocytoma PC12 cells in the presence of nerve growth factor, a series of mono- to tetrasaccharide glycan derivatives were chemically synthesized and evaluated in vitro. The methyl group at C8 of the terminal sialic acid residue was crucial for neuritogenic activity, and the terminal trisaccharide moiety was the minimum active motif. Furthermore, the trisaccharide also stimulated neuritogenesis in human neuroblastoma SH-SY5Y cells via mitogen-activated protein kinase (MAPK) signaling. Phosphorylation of extracellular signal-regulated kinase (ERK) 1/2 was rapidly induced by adding 1 or 10 nM of the trisaccharide. The ratio of phosphorylated ERK to ERK reached a maximum 5 min after stimulation, and then decreased gradually. However, the trisaccharide did not induce significant Akt phosphorylation. These effects were abolished by pretreatment with the MAPK inhibitor U0126, which inhibits enzymes MEK1 and MEK2. In addition, U0126 inhibited the phosphorylation of ERK 1/2 in response to the trisaccharide dose-dependently. Therefore, we concluded that the trisaccharide promotes neurite extension in SH-SY5Y cells via MAPK/ERK signaling, not Akt signaling. PMID:26690179

  19. The ganglioside antigen GD2 is surface-expressed in Ewing sarcoma and allows for MHC-independent immune targeting

    PubMed Central

    Kailayangiri, S; Altvater, B; Meltzer, J; Pscherer, S; Luecke, A; Dierkes, C; Titze, U; Leuchte, K; Landmeier, S; Hotfilder, M; Dirksen, U; Hardes, J; Gosheger, G; Juergens, H; Rossig, C

    2012-01-01

    Background: Novel treatment strategies are needed to cure disseminated Ewing sarcoma. Primitive neuroectodermal features and a mesenchymal stem cell origin are both compatible with aberrant expression of the ganglioside antigen GD2 and led us to explore GD2 immune targeting in this cancer. Methods: We investigated GD2 expression in Ewing sarcoma by immunofluorescence staining. We then assessed the antitumour activity of T cells expressing a chimeric antigen receptor specific for GD2 against Ewing sarcoma in vitro and in vivo. Results: Surface GD2 was detected in 10 out of 10 Ewing sarcoma cell lines and 3 out of 3 primary cell cultures. Moreover, diagnostic biopsies from 12 of 14 patients had uniform GD2 expression. T cells specifically modified to express the GD2-specific chimeric receptor 14. G2a-28ζ efficiently interacted with Ewing sarcoma cells, resulting in antigen-specific secretion of cytokines. Moreover, chimeric receptor gene-modified T cells from healthy donors and from a patient exerted potent, GD2-specific cytolytic responses to allogeneic and autologous Ewing sarcoma, including tumour cells grown as multicellular, anchorage-independent spheres. GD2-specific T cells further had activity against Ewing sarcoma xenografts. Conclusion: GD2 surface expression is a characteristic of Ewing sarcomas and provides a suitable target antigen for immunotherapeutic strategies to eradicate micrometastatic cells and prevent relapse in high-risk disease. PMID:22374462

  20. siRNA-based spherical nucleic acids reverse impaired wound healing in diabetic mice by ganglioside GM3 synthase knockdown.

    PubMed

    Randeria, Pratik S; Seeger, Mark A; Wang, Xiao-Qi; Wilson, Heather; Shipp, Desmond; Mirkin, Chad A; Paller, Amy S

    2015-05-05

    Spherical nucleic acid (SNA) gold nanoparticle conjugates (13-nm-diameter gold cores functionalized with densely packed and highly oriented nucleic acids) dispersed in Aquaphor have been shown to penetrate the epidermal barrier of both intact mouse and human skin, enter keratinocytes, and efficiently down-regulate gene targets. ganglioside-monosialic acid 3 synthase (GM3S) is a known target that is overexpressed in diabetic mice and responsible for causing insulin resistance and impeding wound healing. GM3S SNAs increase keratinocyte migration and proliferation as well as insulin and insulin-like growth factor-1 (IGF1) receptor activation under both normo- and hyperglycemic conditions. The topical application of GM3S SNAs (50 nM) to splinted 6-mm-diameter full-thickness wounds in diet-induced obese diabetic mice decreases local GM3S expression by >80% at the wound edge through an siRNA pathway and fully heals wounds clinically and histologically within 12 d, whereas control-treated wounds are only 50% closed. Granulation tissue area, vascularity, and IGF1 and EGF receptor phosphorylation are increased in GM3S SNA-treated wounds. These data capitalize on the unique ability of SNAs to naturally penetrate the skin and enter keratinocytes without the need for transfection agents. Moreover, the data further validate GM3 as a mediator of the delayed wound healing in type 2 diabetes and support regional GM3 depletion as a promising therapeutic direction.

  1. Differential uPAR recruitment in caveolar-lipid rafts by GM1 and GM3 gangliosides regulates endothelial progenitor cells angiogenesis.

    PubMed

    Margheri, Francesca; Papucci, Laura; Schiavone, Nicola; D'Agostino, Riccardo; Trigari, Silvana; Serratì, Simona; Laurenzana, Anna; Biagioni, Alessio; Luciani, Cristina; Chillà, Anastasia; Andreucci, Elena; Del Rosso, Tommaso; Margheri, Giancarlo; Del Rosso, Mario; Fibbi, Gabriella

    2015-01-01

    Gangliosides and the urokinase plasminogen activator receptor (uPAR) tipically partition in specialized membrane microdomains called lipid-rafts. uPAR becomes functionally important in fostering angiogenesis in endothelial progenitor cells (EPCs) upon recruitment in caveolar-lipid rafts. Moreover, cell membrane enrichment with exogenous GM1 ganglioside is pro-angiogenic and opposite to the activity of GM3 ganglioside. On these basis, we first checked the interaction of uPAR with membrane models enriched with GM1 or GM3, relying on the adoption of solid-supported mobile bilayer lipid membranes with raft-like composition formed onto solid hydrophilic surfaces, and evaluated by surface plasmon resonance (SPR) the extent of uPAR recruitment. We estimated the apparent dissociation constants of uPAR-GM1/GM3 complexes. These preliminary observations, indicating that uPAR binds preferentially to GM1-enriched biomimetic membranes, were validated by identifying a pro-angiogenic activity of GM1-enriched EPCs, based on GM1-dependent uPAR recruitment in caveolar rafts. We have observed that addition of GM1 to EPCs culture medium promotes matrigel invasion and capillary morphogenesis, as opposed to the anti-angiogenesis activity of GM3. Moreover, GM1 also stimulates MAPKinases signalling pathways, typically associated with an angiogenesis program. Caveolar-raft isolation and Western blotting of uPAR showed that GM1 promotes caveolar-raft partitioning of uPAR, as opposed to control and GM3-challenged EPCs. By confocal microscopy, we have shown that in EPCs uPAR is present on the surface in at least three compartments, respectively, associated to GM1, GM3 and caveolar rafts. Following GM1 exogenous addition, the GM3 compartment is depleted of uPAR which is recruited within caveolar rafts thereby triggering angiogenesis.

  2. Intraventricular Sialidase Administration Enhances GM1 Ganglioside Expression and Is Partially Neuroprotective in a Mouse Model of Parkinson’s Disease

    PubMed Central

    Schneider, Jay S.; Seyfried, Thomas N.; Choi, Hyo-S.; Kidd, Sarah K.

    2015-01-01

    Background Preclinical and clinical studies have previously shown that systemic administration of GM1 ganglioside has neuroprotective and neurorestorative properties in Parkinson’s disease (PD) models and in PD patients. However, the clinical development of GM1 for PD has been hampered by its animal origin (GM1 used in previous studies was extracted from bovine brains), limited bioavailability, and limited blood brain barrier penetrance following systemic administration. Objective To assess an alternative therapeutic approach to systemic administration of brain-derived GM1 to enhance GM1 levels in the brain via enzymatic conversion of polysialogangliosides into GM1 and to assess the neuroprotective potential of this approach. Methods We used sialidase from Vibrio cholerae (VCS) to convert GD1a, GD1b and GT1b gangliosides to GM1. VCS was infused by osmotic minipump into the dorsal third ventricle in mice over a 4-week period. After the first week of infusion, animals received MPTP injections (20 mg/kg, s.c., twice daily, 4 hours apart, for 5 consecutive days) and were euthanized 2 weeks after the last injection. Results VCS infusion resulted in the expected change in ganglioside expression with a significant increase in GM1 levels. VCS-treated animals showed significant sparing of striatal dopamine (DA) levels and substantia nigra DA neurons following MPTP administration, with the extent of sparing of DA neurons similar to that achieved with systemic GM1 administration. Conclusion The results suggest that enzymatic conversion of polysialogangliosides to GM1 may be a viable treatment strategy for increasing GM1 levels in the brain and exerting a neuroprotective effect on the damaged nigrostriatal DA system. PMID:26629687

  3. Differential uPAR recruitment in caveolar-lipid rafts by GM1 and GM3 gangliosides regulates endothelial progenitor cells angiogenesis

    PubMed Central

    Margheri, Francesca; Papucci, Laura; Schiavone, Nicola; D'Agostino, Riccardo; Trigari, Silvana; Serratì, Simona; Laurenzana, Anna; Biagioni, Alessio; Luciani, Cristina; Chillà, Anastasia; Andreucci, Elena; Del Rosso, Tommaso; Margheri, Giancarlo; Del Rosso, Mario; Fibbi, Gabriella

    2015-01-01

    Gangliosides and the urokinase plasminogen activator receptor (uPAR) tipically partition in specialized membrane microdomains called lipid-rafts. uPAR becomes functionally important in fostering angiogenesis in endothelial progenitor cells (EPCs) upon recruitment in caveolar-lipid rafts. Moreover, cell membrane enrichment with exogenous GM1 ganglioside is pro-angiogenic and opposite to the activity of GM3 ganglioside. On these basis, we first checked the interaction of uPAR with membrane models enriched with GM1 or GM3, relying on the adoption of solid-supported mobile bilayer lipid membranes with raft-like composition formed onto solid hydrophilic surfaces, and evaluated by surface plasmon resonance (SPR) the extent of uPAR recruitment. We estimated the apparent dissociation constants of uPAR-GM1/GM3 complexes. These preliminary observations, indicating that uPAR binds preferentially to GM1-enriched biomimetic membranes, were validated by identifying a pro-angiogenic activity of GM1-enriched EPCs, based on GM1-dependent uPAR recruitment in caveolar rafts. We have observed that addition of GM1 to EPCs culture medium promotes matrigel invasion and capillary morphogenesis, as opposed to the anti-angiogenesis activity of GM3. Moreover, GM1 also stimulates MAPKinases signalling pathways, typically associated with an angiogenesis program. Caveolar-raft isolation and Western blotting of uPAR showed that GM1 promotes caveolar-raft partitioning of uPAR, as opposed to control and GM3-challenged EPCs. By confocal microscopy, we have shown that in EPCs uPAR is present on the surface in at least three compartments, respectively, associated to GM1, GM3 and caveolar rafts. Following GM1 exogenous addition, the GM3 compartment is depleted of uPAR which is recruited within caveolar rafts thereby triggering angiogenesis. PMID:25313007

  4. Binding of Clostridium botulinum type C and D neurotoxins to ganglioside and phospholipid. Novel insights into the receptor for clostridial neurotoxins.

    PubMed

    Tsukamoto, Kentaro; Kohda, Tomoko; Mukamoto, Masafumi; Takeuchi, Kumiko; Ihara, Hideshi; Saito, Masaki; Kozaki, Shunji

    2005-10-21

    Clostridium botulinum neurotoxins (BoNTs) act on nerve endings to block acetylcholine release. Their potency is due to their enzymatic activity and selective high affinity binding to neurons. Although there are many pieces of data available on the receptor for BoNT, little attempt has been made to characterize the receptors for BoNT/C and BoNT/D. For this purpose, we prepared the recombinant carboxyl-terminal domain of the heavy chain (H(C)) and then examined its binding capability to rat brain synaptosomes treated with enzymes and heating. Synaptosomes treated with proteinase K or heating retained binding capability to both H(C)/C and H(C)/D, suggesting that a proteinaceous substance does not constitute the receptor component. We next performed a thin layer chromatography overlay assay of H(C) with a lipid extract of synaptosomes. Under physiological or higher ionic strengths, H(C)/C bound to gangliosides GD1b and GT1b. These data are in accord with results showing that neuraminidase and endoglycoceramidase treatment decreased H(C)/C binding to synaptosomes. On the other hand, H(C)/D interacted with phosphatidylethanolamine but not with any ganglioside. Using cerebellar granule cells obtained from GM3 synthase knock-out mice, we found that BoNT/C did not elicit a toxic effect but that BoNT/D still inhibited glutamate release to the same extent as in granule cells from wild type mice. These observations suggested that BoNT/C recognized GD1b and GT1b as functional receptors, whereas BoNT/D induced toxicity in a ganglioside-independent manner, possibly through binding to phosphatidylethanolamine. Our results provide novel insights into the receptor for clostridial neurotoxin.

  5. Anti-ganglioside antibodies induced in chickens by an alum-adsorbed anti-idiotype antibody targeting NeuGcGM3

    PubMed Central

    Guthmann, Marcelo D.; Venier, Cecilia; Toledo, Darien; Segatori, Valeria I.; Alonso, Daniel F.; Fainboim, Leonardo; Vázquez, Ana M.; Ostrowski, Hector

    2013-01-01

    Racotumomab is a murine anti-idiotype cancer vaccine targeting NeuGcGM3 on melanoma, breast, and lung cancer. In order to characterize the immunogenicity of alum-adsorbed racotumomab in a non-clinical setting, Leghorn chickens were immunized in dose levels ranging from 25 μg to 1600 μg. Racotumomab was administered subcutaneously in the birds' neck with three identical boosters and serum samples were collected before, during and after the immunization schedule. A strong antibody response was obtained across the evaluated dose range, confirming the immunogenicity of racotumomab even at dose levels as low as 25 μg. As previously observed when using Freund's adjuvant, alum-adsorbed racotumomab induced an idiotype-specific response in all the immunized birds and ganglioside-specific antibodies in 60–100% of the animals. In contrast to the rapid induction anti-idiotype response, detection of ganglioside-specific antibodies in responsive animals may require repeated boosting. Kinetics of anti-NeuGcGM3 antibody titers showed a slight decline 2 weeks after each booster, arguing in favor of repeated immunizations in order to maintain antibody titer. Interestingly, the intensity of the anti-NeuGcGM3 response paralleled that of anti-mucin antibodies and anti-tumor antibodies, suggesting that the in vitro detection of anti-ganglioside antibodies might be a surrogate for an in vivo activity of racotumomab. Taken together, these results suggest that Leghorn chicken immunization might become the means to test the biological activity of racotumomab intended for clinical use. PMID:23335925

  6. Binding of monoclonal antibody AA4 to gangliosides on rat basophilic leukemia cells produces changes similar to those seen with Fc epsilon receptor activation

    PubMed Central

    1992-01-01

    The mAb AA4 binds to novel derivatives of the ganglioside Gd1b on rat basophilic leukemia (RBL-2H3) cells. Some of the gangliosides are located close to the high affinity IgE receptor (Fc epsilon RI), and binding of mAb AA4 inhibits Fc epsilon RI-mediated histamine release. In the present study, mAb AA4 was found to bind exclusively to mast cells in all rat tissues examined. In vitro, within 1 min of mAb AA4 binding, the cells underwent striking morphologic changes. They lost their normal spindle shaped appearance, increased their ruffling, and spread over the surface of the culture dish. These changes were accompanied by a redistribution of the cytoskeletal elements, actin, tubulin, and vimentin, but only the actin was associated with the membrane ruffles. Binding of mAb AA4 also induces a rise in intracellular calcium, stimulates phosphatidyl inositol breakdown, and activates PKC. However, the extent of these changes was less than that observed when the cells were stimulated with antigen or antibody directed against the Fc epsilon RI. None of these changes associated with mAb AA4 binding were seen when the cells were exposed to nonspecific IgG, IgE, or four other anti-cell surface antibodies, nor were the changes induced by binding mAb AA4 at 4 degrees C or in the absence of extracellular calcium. Although mAb AA4 does not stimulate histamine release, it enhances the effect of the calcium ionophore A23187 mediated release. The morphological and biochemical effects produced by mAb AA4 are similar to those seen following activation of the cell through the IgE receptor. Therefore, the surface gangliosides which bind mAb AA4 may function in modulating secretory events. PMID:1370498

  7. A mutation in a ganglioside biosynthetic enzyme, ST3GAL5, results in salt & pepper syndrome, a neurocutaneous disorder with altered glycolipid and glycoprotein glycosylation

    PubMed Central

    Boccuto, Luigi; Aoki, Kazuhiro; Flanagan-Steet, Heather; Chen, Chin-Fu; Fan, Xiang; Bartel, Frank; Petukh, Marharyta; Pittman, Ayla; Saul, Robert; Chaubey, Alka; Alexov, Emil; Tiemeyer, Michael; Steet, Richard; Schwartz, Charles E.

    2014-01-01

    ‘Salt & Pepper’ syndrome is an autosomal recessive condition characterized by severe intellectual disability, epilepsy, scoliosis, choreoathetosis, dysmorphic facial features and altered dermal pigmentation. High-density SNP array analysis performed on siblings first described with this syndrome detected four shared regions of loss of heterozygosity (LOH). Whole-exome sequencing narrowed the candidate region to chromosome 2p11.2. Sanger sequencing confirmed a homozygous c.994G>A transition (p.E332K) in the ST3GAL5 gene, which encodes for a sialyltransferase also known as GM3 synthase. A different homozygous mutation of this gene has been previously associated with infantile-onset epilepsy syndromes in two other cohorts. The ST3GAL5 enzyme synthesizes ganglioside GM3, a glycosophingolipid enriched in neural tissue, by adding sialic acid to lactosylceramide. Unlike disorders of glycosphingolipid (GSL) degradation, very little is known regarding the molecular and pathophysiologic consequences of altered GSL biosynthesis. Glycolipid analysis confirmed a complete lack of GM3 ganglioside in patient fibroblasts, while microarray analysis of glycosyltransferase mRNAs detected modestly increased expression of ST3GAL5 and greater changes in transcripts encoding enzymes that lie downstream of ST3GAL5 and in other GSL biosynthetic pathways. Comprehensive glycomic analysis of N-linked, O-linked and GSL glycans revealed collateral alterations in response to loss of complex gangliosides in patient fibroblasts and in zebrafish embryos injected with antisense morpholinos that targeted zebrafish st3gal5 expression. Morphant zebrafish embryos also exhibited increased apoptotic cell death in multiple brain regions, emphasizing the importance of GSL expression in normal neural development and function. PMID:24026681

  8. Association of antibodies to ganglioside complexes and conduction blocks in axonal Guillain-Barré syndrome presenting as acute motor conduction block neuropathy.

    PubMed

    Créange, Alain; Shahrizaila, Nortina; Salhi, Hayet; Lefaucheur, Jean-Pascal; Yuki, Nobuhiro

    2014-06-01

    A close relationship between acute motor conduction block neuropathy and antibodies against the complex of GM1 and GalNAc-GD1a has been reported. This study investigates the hypothesis that conduction block at the early phase of axonal Guillain-Barré syndrome (GBS) is also associated with such ganglioside complexes. Sera were obtained from seven French patients with initial evidence of isolated conduction blocks that resolved or progressed to acute motor axonal neuropathy. Serum IgG to asialo-GM1 and gangliosides of LM1, GM1, GM1b, GD1a, GalNAc-GD1a, GD1b, GT1a, GT1b, and GQ1b as well as their complexes were measured. Five of seven patients progressed within the first month of disease to AMAN. One patient had IgG antibodies against the complex of asialo-GM1 and each of the other ganglioside antigens. Another patient carried IgG antibodies against GM1 complex with GM1b, GD1a, and GT1a as well as asialo-GM1 complex with GD1a and GT1a. None had IgG antibodies against GM1/GalNAc-GD1a complex. Six patients had IgG against single antigens GM1, GD1a, GalNAc-GD1a, GD1b, and asialo-GM1. In three patients, a reduced reaction against GM1/GalNAc-GD1a complex was observed. The presence of conduction block in axonal GBS is not always associated with anti-GM1/GalNAc-GD1a complex antibodies.

  9. Motor conduction block and high titres of anti-GM1 ganglioside antibodies: pathological evidence of a motor neuropathy in a patient with lower motor neuron syndrome.

    PubMed Central

    Adams, D; Kuntzer, T; Steck, A J; Lobrinus, A; Janzer, R C; Regli, F

    1993-01-01

    A patient with a progressive lower motor neuron syndrome and neurophysiological evidence of motor axon loss, multifocal proximal motor nerve conduction block, and high titres of anti-ganglioside GM1 antibodies. Neuropathological findings included a predominantly proximal motor radiculoneuropathy with multifocal IgG and IgM deposits on nerve fibres associated with a loss of spinal motor neurons. These findings support an autoimmune origin of this lower motor neuron syndrome with retrograde degeneration of spinal motor neurons and severe neurogenic muscular atrophy. Images PMID:8410039

  10. The β-subunit of cholera toxin has a high affinity for ganglioside GM1 embedded into solid supported lipid membranes with a lipid raft-like composition.

    PubMed

    Margheri, G; D'Agostino, R; Trigari, S; Sottini, S; Del Rosso, M

    2014-02-01

    In this communication, we report on the fabrication of GM1-rich solid-supported bilayer lipid membranes (ssBLM) made of sphingomyelin and cholesterol, the main components of lipid rafts,which are the physiological hosting microenvironment of GM1 on the cell membrane. The functionality of the ganglioside has been checked by measuring the apparent dissociation constant K(D) of the complex formed by the β-subunit of the cholera toxin and GM1. The value found deviates less than one order of magnitude from that measured for in vivo cells, indicating the potential of these ssBLM as optimized in vitro biomimetic platforms.

  11. Prognostic Significance of N-Glycolyl GM3 Ganglioside Expression in Non-Small Cell Lung Carcinoma Patients: New Evidences

    PubMed Central

    Blanco, Rancés; Domínguez, Elizabeth; Morales, Orlando; Blanco, Damián; Martínez, Darel; Rengifo, Charles E.; Viada, Carmen; Cedeño, Mercedes; Rengifo, Enrique; Carr, Adriana

    2015-01-01

    The prognostic role of N-glycolyl GM3 ganglioside (NeuGcGM3) expression in non-small cell lung carcinoma (NSCLC) still remains controversial. In this study, the NeuGcGM3 expression was reevaluated using an increased number of NSCLC cases and the 14F7 Mab (a highly specific IgG1 raised against NeuGcGM3). An immunohistochemical score integrating the percentage of 14F7-positive cells and the intensity of reaction was applied to reassess the relationship between NeuGcGM3 expression, some clinicopathological features, and the overall survival (OS) of NSCLC patients. The double and the triple expression of NeuGcGM3 with the epidermal growth factor receptor (EGFR) and/or its ligand, the epidermal growth factor (EGF), were also evaluated. NeuGcGM3 expression correlates with both S-Phase fraction (p = 0.006) and proliferation index (p = 0.000). Additionally, NeuGcGM3 expression was associated with a poor OS of patients in both univariate (p = 0.020) and multivariate (p = 0.010) analysis. Moreover, the double and/or the triple positivity of tumors to NeuGcGM3, EGFR, and/or EGF permitted us to identify phenotypes of NSCLC with a more aggressive biological behavior. Our results are in agreement with the negative prognostic significance of NeuGcGM3 expression in NSCLC patients. However, standardization of techniques to determine the expression of NeuGcGM3 in NSCLC as well as the implementation of a universal scoring system is recommended. PMID:26634172

  12. A natural human IgM that binds to gangliosides is therapeutic in murine models of amyotrophic lateral sclerosis

    PubMed Central

    Xu, Xiaohua; Denic, Aleksandar; Jordan, Luke R.; Wittenberg, Nathan J.; Warrington, Arthur E.; Wootla, Bharath; Papke, Louisa M.; Zoecklein, Laurie J.; Yoo, Daehan; Shaver, Jonah; Oh, Sang-Hyun; Pease, Larry R.; Rodriguez, Moses

    2015-01-01

    ABSTRACT Amyotrophic lateral sclerosis (ALS) is a devastating, fatal neurological disease that primarily affects spinal cord anterior horn cells and their axons for which there is no treatment. Here we report the use of a recombinant natural human IgM that binds to the surface of neurons and supports neurite extension, rHIgM12, as a therapeutic strategy in murine models of human ALS. A single 200 µg intraperitoneal dose of rHIgM12 increases survival in two independent genetic-based mutant SOD1 mouse strains (SOD1G86R and SOD1G93A) by 8 and 10 days, delays the onset of neurological deficits by 16 days, delays the onset of weight loss by 5 days, and preserves spinal cord axons and anterior horn neurons. Immuno-overlay of thin layer chromatography and surface plasmon resonance show that rHIgM12 binds with high affinity to the complex gangliosides GD1a and GT1b. Addition of rHIgM12 to neurons in culture increases α-tubulin tyrosination levels, suggesting an alteration of microtubule dynamics. We previously reported that a single peripheral dose of rHIgM12 preserved neurological function in a murine model of demyelination with axon loss. Because rHIgM12 improves three different models of neurological disease, we propose that the IgM might act late in the cascade of neuronal stress and/or death by a broad mechanism. PMID:26035393

  13. Gangliosides, Ab1 and Ab2 antibodies II. Light versus heavy chain: An idiotype-anti-idiotype case study.

    PubMed

    López-Requena, Alejandro; Rodríguez, Mabel; de Acosta, Cristina Mateo; Moreno, Ernesto; Puchades, Yaquelin; González, Majela; Talavera, Ariel; Valle, Aisel; Hernández, Tays; Vázquez, Ana María; Pérez, Rolando

    2007-02-01

    The antibody heavy chain is generally more important than the light chain for the interaction with the antigen, although many reports demonstrate the influence of the light chain in the antibody binding properties. The heavy chains of anti-N-glycolyl-ganglioside P3 mAb and anti-idiotypic 1E10 mAb display complementary charged residues in their H-CDRs, particularly in H-CDR3. A basic residue in P3 mAb H-CDR1 was shown to be crucial for the interaction with the antigen and 1E10 mAb. The immunogenetic features of three other P3 mAb anti-idiotypic mAbs are now analyzed. One of them bears the same heavy chain as 1E10 mAb and a different light chain, but differs in its binding to P3 mAb mutants where H-CDR basic residues were replaced and in the binding to 1E10-specific phagotopes. Chimeric hybrid antibodies with P3 and 1E10 mAb heavy chains and unrelated light chains were obtained to further determine the importance of heavy chains in P3 and 1E10 mAb binding properties. One of the P3 heavy chain hybrid antibodies retained the specificity of P3 mAb with slight affinity differences. The heavy chains appear to play the main role in these mAb interactions, with the light chains modulating the affinity to their ligands.

  14. Compound porcine cerebroside and ganglioside injection attenuates cerebral ischemia–reperfusion injury in rats by targeting multiple cellular processes

    PubMed Central

    Wang, Mingyang; Zhang, Yi; Feng, Lu; Zheng, Ji; Fan, Shujie; Liu, Junya; Yang, Nan; Liu, Yanyong; Zuo, Pingping

    2017-01-01

    Background Compound porcine cerebroside and ganglioside injection (CPCGI) is a neurotrophic drug used clinically to treat certain functional disorders of brain. Despite its extensive usage throughout China, the exact mechanistic targets of CPCGI are unknown. This study was carried out to investigate the protective effect of CPCGI against ischemic neuronal damage in rats with middle cerebral artery occlusion (MCAO) reperfusion injury and to investigate the neuroprotective mechanisms of CPCGI. Materials and methods Adult male Sprague-Dawley rats were subjected to MCAO surgery for 2 hours followed by reperfusion. The rats were administered CPCGI once a day for 14 days after reperfusion, and behavioral tests were performed 1, 3, 7, and 14 days post MCAO. Hematoxylin–eosin staining was used to measure infarct volume, and immunohistochemical analysis was performed to determine the number of NeuN-positive neurons in the ischemic cortex penumbra. Finally, the relative expression levels of proteins associated with apoptosis (Bcl-2, Bax, and GADD45α), synaptic function (Synaptophysin, SNAP25, Syntaxin, and Complexin-1/2), and mitochondrial function (KIFC2 and UCP3) were determined by Western blot. Results CPCGI treatment reduced infarct size, decreased neurological deficit scores, and accelerated the recovery of somatosensory function 14 days after MCAO. In addition, CPCGI reduced the loss of NeuN-positive cells in the ischemic cortex penumbra. In the ischemic cortex, CPCGI treatment decreased GADD45α expression, increased the Bcl-2/Bax ratio, augmented Synaptophysin, SNAP25, and Complexin-1/2 expression, and increased the expression of KIFC2 and UCP3 compared with sham rats 14 days after MCAO reperfusion injury. Conclusion CPCGI displays neuroprotective properties in rats subjected to MCAO injury by inhibiting apoptosis and improving synaptic and mitochondrial function. PMID:28392696

  15. Treatment of neuroblastoma meningeal carcinomatosis with intrathecal application of alpha-emitting atomic nanogenerators targeting disialo-ganglioside GD2.

    PubMed

    Miederer, Matthias; McDevitt, Michael R; Borchardt, Paul; Bergman, Ira; Kramer, Kim; Cheung, Nai-Kong V; Scheinberg, David A

    2004-10-15

    Labeling of specific antibodies with bifunctional chelated Actinium-225 ((225)Ac; an alpha generator) allows the formation of new, highly potent and selective alpha-emitting anticancer drugs. We synthesized and evaluated a radioimmunoconjugate based on 3F8, an IgG(3) antibody that specifically binds to ganglioside GD2, which is overexpressed by many neuroectodermal tumors including neuroblastoma. The (225)Ac-1,4,7,10-tetra-azacylododecane (DOTA)-3F8 construct was evaluated for radiochemical purity and sterility, immunoreactivity, cytotoxicity in vitro, induction of apoptosis on GD2-positive cells, as well as for pharmacological biodistribution and metabolism of the (225)Ac generator and its daughters in a nude mouse xenograft model of neuroblastoma. The (225)Ac-3F8 showed an IC(50) of 3 Bq/ml (80 pCi/ml) on the neuroblastoma cell line, NMB7, in vitro. Apoptosis of these cells was not observed. Biodistribution in mice showed specific targeting of a subcutaneous tumor; there was redistribution of the (225)Ac daughter nuclides mainly from blood to kidneys and to small intestine. Toxicity was examined in cynomolgus monkeys. Monkeys injected with 1 to 3 doses of intrathecal (225)Ac-3F8 radioimmunoconjugate (80 to 150 kBq/kg total dose) did not show signs of toxicity based on blood chemistry, complete blood counts, or by clinical evaluations. Therapeutic efficacy of intrathecal (225)Ac-3F8 was studied in a nude rat xenograft model of meningeal carcinomatosis. The (225)Ac-3F8 treatment improved survival 2-fold from 16 to 34 days (P = 0.01). In conclusion, in vivo alpha generators targeted by 3F8 warrant additional study as a possible new approach to the treatment of carcinomatous meningitis.

  16. Prognostic Significance of N-Glycolyl GM3 Ganglioside Expression in Non-Small Cell Lung Carcinoma Patients: New Evidences.

    PubMed

    Blanco, Rancés; Domínguez, Elizabeth; Morales, Orlando; Blanco, Damián; Martínez, Darel; Rengifo, Charles E; Viada, Carmen; Cedeño, Mercedes; Rengifo, Enrique; Carr, Adriana

    2015-01-01

    The prognostic role of N-glycolyl GM3 ganglioside (NeuGcGM3) expression in non-small cell lung carcinoma (NSCLC) still remains controversial. In this study, the NeuGcGM3 expression was reevaluated using an increased number of NSCLC cases and the 14F7 Mab (a highly specific IgG1 raised against NeuGcGM3). An immunohistochemical score integrating the percentage of 14F7-positive cells and the intensity of reaction was applied to reassess the relationship between NeuGcGM3 expression, some clinicopathological features, and the overall survival (OS) of NSCLC patients. The double and the triple expression of NeuGcGM3 with the epidermal growth factor receptor (EGFR) and/or its ligand, the epidermal growth factor (EGF), were also evaluated. NeuGcGM3 expression correlates with both S-Phase fraction (p = 0.006) and proliferation index (p = 0.000). Additionally, NeuGcGM3 expression was associated with a poor OS of patients in both univariate (p = 0.020) and multivariate (p = 0.010) analysis. Moreover, the double and/or the triple positivity of tumors to NeuGcGM3, EGFR, and/or EGF permitted us to identify phenotypes of NSCLC with a more aggressive biological behavior. Our results are in agreement with the negative prognostic significance of NeuGcGM3 expression in NSCLC patients. However, standardization of techniques to determine the expression of NeuGcGM3 in NSCLC as well as the implementation of a universal scoring system is recommended.

  17. Interaction between Simian Virus 40 Major Capsid Protein VP1 and Cell Surface Ganglioside GM1 Triggers Vacuole Formation

    PubMed Central

    Luo, Yong; Motamedi, Nasim; Magaldi, Thomas G.; Gee, Gretchen V.; Atwood, Walter J.

    2016-01-01

    ABSTRACT Simian virus 40 (SV40), a polyomavirus that has served as an important model to understand many aspects of biology, induces dramatic cytoplasmic vacuolization late during productive infection of monkey host cells. Although this activity led to the discovery of the virus in 1960, the mechanism of vacuolization is still not known. Pentamers of the major SV40 capsid protein VP1 bind to the ganglioside GM1, which serves as the cellular receptor for the virus. In this report, we show that binding of VP1 to cell surface GM1 plays a key role in SV40 infection-induced vacuolization. We previously showed that SV40 VP1 mutants defective for GM1 binding fail to induce vacuolization, even though they replicate efficiently. Here, we show that interfering with GM1-VP1 binding by knockdown of GM1 after infection is established abrogates vacuolization by wild-type SV40. Vacuole formation during permissive infection requires efficient virus release, and conditioned medium harvested late during SV40 infection rapidly induces vacuoles in a VP1- and GM1-dependent fashion. Furthermore, vacuolization can also be induced by a nonreplicating SV40 pseudovirus in a GM1-dependent manner, and a mutation in BK pseudovirus VP1 that generates GM1 binding confers vacuole-inducing activity. Vacuolization can also be triggered by purified pentamers of wild-type SV40 VP1, but not by GM1 binding-defective pentamers or by intracellular expression of VP1. These results demonstrate that SV40 infection-induced vacuolization is caused by the binding of released progeny viruses to GM1, thereby identifying the molecular trigger for the activity that led to the discovery of SV40. PMID:27006465

  18. Ganglioside contained in the neuronal tissue-enriched acidic protein of 22 kDa (NAP-22) fraction prepared from the detergent-resistant membrane microdomain of rat brain inhibits the phosphatase activity of calcineurin.

    PubMed

    Kobayashi, Yuumi; da Silva, Ronan; Kumanogoh, Haruko; Miyata, Shinji; Sato, Chihiro; Kitajima, Ken; Nakamura, Shun; Morita, Mistuhiro; Hayashi, Fumio; Maekawa, Shohei

    2015-09-01

    Neurons have well-developed membrane microdomains called "rafts" that are recovered as a detergent-resistant membrane microdomain fraction (DRM). Neuronal tissue-enriched acidic protein of 22 kDa (NAP-22) is one of the major protein components of neuronal DRM. To determine the cellular function of NAP-22, interacting proteins were screened with an immunoprecipitation assay, and calcineurin (CaN) was detected. Further studies with NAP-22 prepared from DRM and CaN expressed in bacteria showed the binding of these proteins and a dose-dependent inhibitory effect of the NAP-22 fraction on the phosphatase activity of CaN. On the other hand, NAP-22 expressed in bacteria showed low binding to CaN and a weak inhibitory effect on phosphatase activity. To solve this discrepancy, identification of a nonprotein component that modulates CaN activity in the DRM-derived NAP-22 fraction was attempted. After lyophilization, a lipid fraction was extracted with chloroform/methanol. The lipid fraction showed an inhibitory effect on CaN without NAP-22, and further fractionation of the extract with thin-layer chromatography showed the presence of several lipid bands having an inhibitory effect on CaN. The mobility of these bands coincided with that of authentic ganglioside (GM1a, GD1a, GD1b, and GT1b), and authentic ganglioside showed an inhibitory effect on CaN. Treatment of lipid with endoglycoceramidase, which degrades ganglioside to glycochain and ceramide, caused a diminution of the inhibitory effect. These results show that DRM-derived NAP-22 binds several lipids, including ganglioside, and that ganglioside inhibits the phosphatase activity of CaN.

  19. Ganglioside GM1-mediated transcytosis of cholera toxin bypasses the retrograde pathway and depends on the structure of the ceramide domain.

    PubMed

    Saslowsky, David E; te Welscher, Yvonne M; Chinnapen, Daniel J-F; Wagner, Jessica S; Wan, Joy; Kern, Eli; Lencer, Wayne I

    2013-09-06

    Cholera toxin causes diarrheal disease by binding ganglioside GM1 on the apical membrane of polarized intestinal epithelial cells and trafficking retrograde through sorting endosomes, the trans-Golgi network (TGN), and into the endoplasmic reticulum. A fraction of toxin also moves from endosomes across the cell to the basolateral plasma membrane by transcytosis, thus breeching the intestinal barrier. Here we find that sorting of cholera toxin into this transcytotic pathway bypasses retrograde transport to the TGN. We also find that GM1 sphingolipids can traffic from apical to basolateral membranes by transcytosis in the absence of toxin binding but only if the GM1 species contain cis-unsaturated or short acyl chains in the ceramide domain. We found previously that the same GM1 species are needed to efficiently traffic retrograde into the TGN and endoplasmic reticulum and into the recycling endosome, implicating a shared mechanism of action for sorting by lipid shape among these pathways.

  20. Crystallographic structure of human beta-hexosaminidase A: interpretation of Tay-Sachs mutations and loss of GM2 ganglioside hydrolysis.

    PubMed

    Lemieux, M Joanne; Mark, Brian L; Cherney, Maia M; Withers, Stephen G; Mahuran, Don J; James, Michael N G

    2006-06-16

    Lysosomal beta-hexosaminidase A (Hex A) is essential for the degradation of GM2 gangliosides in the central and peripheral nervous system. Accumulation of GM2 leads to severely debilitating neurodegeneration associated with Tay-Sachs disease (TSD), Sandoff disease (SD) and AB variant. Here, we present the X-ray crystallographic structure of Hex A to 2.8 A resolution and the structure of Hex A in complex with NAG-thiazoline, (NGT) to 3.25 A resolution. NGT, a mechanism-based inhibitor, has been shown to act as a chemical chaperone that, to some extent, prevents misfolding of a Hex A mutant associated with adult onset Tay Sachs disease and, as a result, increases the residual activity of Hex A to a level above the critical threshold for disease. The crystal structure of Hex A reveals an alphabeta heterodimer, with each subunit having a functional active site. Only the alpha-subunit active site can hydrolyze GM2 gangliosides due to a flexible loop structure that is removed post-translationally from beta, and to the presence of alphaAsn423 and alphaArg424. The loop structure is involved in binding the GM2 activator protein, while alphaArg424 is critical for binding the carboxylate group of the N-acetyl-neuraminic acid residue of GM2. The beta-subunit lacks these key residues and has betaAsp452 and betaLeu453 in their place; the beta-subunit therefore cleaves only neutral substrates efficiently. Mutations in the alpha-subunit, associated with TSD, and those in the beta-subunit, associated with SD are discussed. The effect of NGT binding in the active site of a mutant Hex A and its effect on protein function is discussed.

  1. Cholesterol accelerates the binding of Alzheimer's β-amyloid peptide to ganglioside GM1 through a universal hydrogen-bond-dependent sterol tuning of glycolipid conformation.

    PubMed

    Fantini, Jacques; Yahi, Nouara; Garmy, Nicolas

    2013-01-01

    Age-related alterations of membrane lipids in brain cell membranes together with high blood cholesterol are considered as major risk factors for Alzheimer's disease. Yet the molecular mechanisms by which these factors increase Alzheimer's risk are mostly unknown. In lipid raft domains of the plasma membrane, neurotoxic Alzheimer's beta-amyloid (Abeta) peptides interact with both cholesterol and ganglioside GM1. Recent data also suggested that cholesterol could stimulate the binding of Abeta to GM1 through conformational modulation of the ganglioside headgroup. Here we used a combination of physicochemical and molecular modeling approaches to decipher the mechanisms of cholesterol-assisted binding of Abeta to GM1. With the aim of decoupling the effect of cholesterol on GM1 from direct Abeta-cholesterol interactions, we designed a minimal peptide (Abeta5-16) containing the GM1-binding domain but lacking the amino acid residues involved in cholesterol recognition. Using the Langmuir technique, we showed that cholesterol (but not phosphatidylcholine or sphingomyelin) significantly accelerates the interaction of Abeta5-16 with GM1. Molecular dynamics simulations suggested that Abeta5-16 interacts with a cholesterol-stabilized dimer of GM1. The main structural effect of cholesterol is to establish a hydrogen-bond between its own OH group and the glycosidic-bond linking ceramide to the glycone part of GM1, thereby inducing a tilt in the glycolipid headgroup. This fine conformational tuning stabilizes the active conformation of the GM1 dimer whose headgroups, oriented in two opposite directions, form a chalice-shaped receptacle for Abeta. These data give new mechanistic insights into the stimulatory effect of cholesterol on Abeta/GM1 interactions. They also support the emerging concept that cholesterol is a universal modulator of protein-glycolipid interactions in the broader context of membrane recognition processes.

  2. Identification of gangliosides recognized by IgG anti-GalNAc-GD1a antibodies in bovine spinal motor neurons and motor nerves.

    PubMed

    Yoshino, Hiide; Ariga, Toshio; Suzuki, Akemi; Yu, Robert K; Miyatake, Tadashi

    2008-08-28

    The presence of immunoglobulin G (IgG)-type antibodies to the ganglioside, N-acetylgalactosaminyl GD1a (GalNAc-GD1a), is closely associated with the pure motor type of Guillain-Barré syndrome (GBS). In the present study, we isolated disialogangliosides from the motor neurons and motor nerves of bovine spinal cords by DEAE-Sephadex column chromatography. The disialoganglioside fraction contained GD1a, GD2, GD1b, and three gangliosides, designated X1, X2 and X3. Serum from a patient with axonal GBS with IgG anti-GalNAc-GD1a antibody yielded positive immunostaining with X1, X2, and X3. When isolated by preparative thin-layer chromatography (TLC), X1 migrated at the same position as GalNAc-GD1a from Tay-Sachs brain, suggesting that X1 is GalNAc-GD1a containing N-acetylneuraminic acid (NeuAc). TLC of isolated X2 revealed that it migrated between GD1a and GD2. On the other hand, X3 had a migratory rate on TLC between and GD1b and GT1b. Since both X2 and X3 were recognized by IgG anti-GalNAc-GD1a antibody, the results suggest that X2 is a GalNAc-GD1a species containing a mixture containing a NeuAc-and an N-glycolylneuraminic acid (NeuGc) species, and X3 is a GalNAc-GD1a species with two NeuGc. This evidence indicating the specific localization of GalNAc-GD1a and its isomers in spinal motor neurons should be useful in elucidating the pathogenic role of IgG anti-GalNAc-GD1a antibody in pure motor-type GBS.

  3. Immunoreactivity of the 14F7 Mab Raised against N-Glycolyl GM3 Ganglioside in Primary Lymphoid Tumors and Lymph Node Metastasis.

    PubMed

    Blanco, Rancés; Blanco, Damián; Quintana, Yisel; Escobar, Xiomara; Rengifo, Charles E; Osorio, Marta; Gutiérrez, Zailí; Lamadrid, Janet; Cedeño, Mercedes; Frómeta, Milagros; Carr, Adriana; Rengifo, Enrique

    2013-01-01

    The reactivity of the 14F7 Mab, a highly specific IgG1 against N-glycolyl GM3 ganglioside (NeuGcGM3) in normal tissues, lymphomas, lymph node metastasis, and other metastatic sites was assessed by immunohistochemistry. In addition, the effect of chemical fixation on the 14F7 Mab staining using monolayers of P3X63Ag.653 cells was also evaluated. Moreover, the ability of 14F7 to bind NeuGcGM3 ganglioside inducing complement-independent cytotoxicity by a flow cytometry-based assay was measured. The 14F7 Mab was reactive in unfixed, 4% paraformaldehyde, 4% formaldehyde, and acetone fixed cells. Postfixation with acetone did not alter the localization of NeuGcGM3, while the staining with 14F7 Mab was significantly eliminated in both cells fixed and postfixed with methanol but only partially reduced with ethanol. The staining with 14F7 Mab was evidenced in the 89.2%, 89.4%, and 88.9% of lymphomas, lymph node metastasis, and other metastatic sites, respectively, but not in normal tissues. The treatment with 14F7 Mab affected both morphology and membrane integrity of P3X63Ag.653 cells. This cytotoxic activity was dose-dependent and ranged from 24.0 to 84.7% (10-1000  μ g/mL) as compared to the negative control. Our data could support the possible use of NeuGcGM3 as target for both active and passive immunotherapy against malignancies expressing this molecule.

  4. Immunoreactivity of the 14F7 Mab Raised against N-Glycolyl GM3 Ganglioside in Primary Lymphoid Tumors and Lymph Node Metastasis

    PubMed Central

    Blanco, Rancés; Blanco, Damián; Quintana, Yisel; Escobar, Xiomara; Rengifo, Charles E.; Osorio, Marta; Gutiérrez, Zailí; Lamadrid, Janet; Cedeño, Mercedes; Frómeta, Milagros; Carr, Adriana; Rengifo, Enrique

    2013-01-01

    The reactivity of the 14F7 Mab, a highly specific IgG1 against N-glycolyl GM3 ganglioside (NeuGcGM3) in normal tissues, lymphomas, lymph node metastasis, and other metastatic sites was assessed by immunohistochemistry. In addition, the effect of chemical fixation on the 14F7 Mab staining using monolayers of P3X63Ag.653 cells was also evaluated. Moreover, the ability of 14F7 to bind NeuGcGM3 ganglioside inducing complement-independent cytotoxicity by a flow cytometry-based assay was measured. The 14F7 Mab was reactive in unfixed, 4% paraformaldehyde, 4% formaldehyde, and acetone fixed cells. Postfixation with acetone did not alter the localization of NeuGcGM3, while the staining with 14F7 Mab was significantly eliminated in both cells fixed and postfixed with methanol but only partially reduced with ethanol. The staining with 14F7 Mab was evidenced in the 89.2%, 89.4%, and 88.9% of lymphomas, lymph node metastasis, and other metastatic sites, respectively, but not in normal tissues. The treatment with 14F7 Mab affected both morphology and membrane integrity of P3X63Ag.653 cells. This cytotoxic activity was dose-dependent and ranged from 24.0 to 84.7% (10–1000 μg/mL) as compared to the negative control. Our data could support the possible use of NeuGcGM3 as target for both active and passive immunotherapy against malignancies expressing this molecule. PMID:24381785

  5. Neuroprotective Ganglioside Derivatives

    DTIC Science & Technology

    2006-09-01

    determined to have therapeutic potential were to be tested in vitro for their ability to cross a brain capillary endothelial cell culture model of...the BBB. Finally, derivatives that were both cytoprotective and that effectively crossed the in vitro BBB model were to be tested in vivo for their...phenylpyridinium (MPP+) and the SH-SY5Y human neuroblastoma cell line. Derivatives determined to have therapeutic potential are tested in vitro for their

  6. Ganglioside GM2 N-acetyl-beta-D-galactosaminidase activity in cultured fibroblasts of late-infantile and adult GM2 gangliosidosis patients and of healthy probands with low hexosaminidase level.

    PubMed Central

    Conzelmann, E; Kytzia, H J; Navon, R; Sandhoff, K

    1983-01-01

    A sensitive assay was developed to assess the ability of extracts from cultured fibroblasts to catabolize ganglioside GM2, in the presence of the natural activator protein but without detergents. This method, which permitted the reliable determination of residual activities as low as 0.1% of normal controls, was then used to measure ganglioside GM2 hydrolase activities in fibroblasts from several hexosaminidase variants. The residual activities thus determined correlated well with the clinical status of the respective proband: infantile Tay-Sachs (0.1% of normal controls), late-infantile (0.5%), and adult GM2 gangliosidoses (2%-4%) and healthy probands with "low hexosaminidase" (11% and 20%). In contrast, beta-hexosaminidase A levels as measured with the synthetic substrate 4-MU-GlcNAc could not be relied on for diagnostic purposes (the late-infantile patient studied retained 80% of the activity of controls). PMID:6614006

  7. Intracranial V. cholerae Sialidase Protects against Excitotoxic Neurodegeneration

    PubMed Central

    Dhanushkodi, Anandh; McDonald, Michael P.

    2011-01-01

    Converging evidence shows that GD3 ganglioside is a critical effector in a number of apoptotic pathways, and GM1 ganglioside has neuroprotective and noötropic properties. Targeted deletion of GD3 synthase (GD3S) eliminates GD3 and increases GM1 levels. Primary neurons from GD3S−/− mice are resistant to neurotoxicity induced by amyloid-β or hyperhomocysteinemia, and when GD3S is eliminated in the APP/PSEN1 double-transgenic model of Alzheimer's disease the plaque-associated oxidative stress and inflammatory response are absent. To date, no small-molecule inhibitor of GD3S exists. In the present study we used sialidase from Vibrio cholerae (VCS) to produce a brain ganglioside profile that approximates that of GD3S deletion. VCS hydrolyzes GD1a and complex b-series gangliosides to GM1, and the apoptogenic GD3 is degraded. VCS was infused by osmotic minipump into the dorsal third ventricle in mice over a 4-week period. Sensorimotor behaviors, anxiety, and cognition were unaffected in VCS-treated mice. To determine whether VCS was neuroprotective in vivo, we injected kainic acid on the 25th day of infusion to induce status epilepticus. Kainic acid induced a robust lesion of the CA3 hippocampal subfield in aCSF-treated controls. In contrast, all hippocampal regions in VCS-treated mice were largely intact. VCS did not protect against seizures. These results demonstrate that strategic degradation of complex gangliosides and GD3 can be used to achieve neuroprotection without adversely affecting behavior. PMID:22195039

  8. Ligands Binding to Cell Surface Ganglioside GD2 Cause Src-Dependent Activation of N-Methyl-D-Aspartate Receptor Signaling and Changes in Cellular Morphology

    PubMed Central

    Gagnon, Martin; Saragovi, H. Uri

    2015-01-01

    Ganglioside GD2 is a plasma membrane glycosphinogolipid. In healthy adults it is expressed at low levels, but it is over-expressed in many cancers. For cancer therapy, GD2 is targeted with anti-GD2 monoclonal antibodies (mAbs), and one adverse side effect is severe visceral pain. Pain is not neuropathic, cannot be blocked with morphine, and stops on discontinuation of mAb therapy. Here, we provide evidence that ligand binding to cell surface GD2 induces rapid and transient activation of Src-family kinases, followed by Src-dependent phosphorylation of NMDA-receptor NR2B subunits selectively, activation of Ca++ fluxes, production of cAMP, and changes in cellular morphology. These GD2-ligand activated signals differ in kinetics and in pharmacology from activation of the same signals in the same cells by BDNF, the growth factor agonist of the TrkB receptor, suggesting biological specificity. Hence, cell surface GD2 regulates pathways that can be associated with neoplasia and with morphine-intractable pain; and this can explain why expression of GD2 correlates with these two pathologies. PMID:26252487

  9. GM1 ganglioside reduces the motor incoordination and loss of righting reflex caused by acute ethanol in C57BL/6J mice

    SciTech Connect

    Wallis, C.; Rezazadeh, S.M.; Forster, M.J.; Lal, H. )

    1992-02-26

    Ethanol produces its intoxicating effects by modifying neuronal membranes. Gangliosides stabilize neuronal membranes and promote their recovery from a variety of insults. In this experiment, the efficacy of GM1(i.p.) to reverse ethanol intoxication was evaluated in male mice trained to run on a constantly accelerating rotorod. When mice were tested 15-min following saline or ethanol GM1 pre-treatment reduced rotorod performance by 15% but was ineffective in modifying the ethanol-impaired performance. However, when mice were tested at 15, 35, 55, 75, and 95 min intervals following ethanol, GM1 pre-treatments dose-dependently reduced the efficacy and duration of ethanol in producing motor incoordination. Further, GM1 given prior to ethanol significantly prolonged the time to onset of the loss of righting reflex from 1.4 to 1.9 min, and reduced the duration of the righting-reflex loss from 94 to 77 min. This GM1 effect was seen at 24 h, but not at 48 or 72 h after its administration. The blood ethanol concentration at awakening was significantly higher in 24h GM1-treated animals than in controls suggesting that the GM1 effect was not due to an alteration in ethanol clearance. These findings support the hypothesis that GM1 promotes recovery from ethanol intoxication via a neuroprotective mechanism.

  10. Examination of the biological role of the alpha(2-->6)-linked sialic acid in gangliosides binding to the myelin-associated glycoprotein (MAG).

    PubMed

    Schwardt, Oliver; Gäthje, Heiko; Vedani, Angelo; Mesch, Stefanie; Gao, Gan-Pan; Spreafico, Morena; von Orelli, Johannes; Kelm, Sørge; Ernst, Beat

    2009-02-26

    The tetrasaccharide 1, a substructure of ganglioside GQ1b alpha, shows a remarkable affinity for the myelin-associated glycoprotein (MAG) and was therefore selected as starting point for a lead optimization program. In our search for structurally simplified and pharmacokinetically improved mimics of 1, modifications of the core disaccharide, the alpha(2-->3)- and the alpha(2-->6)-linked sialic acid were synthesized. Biphenylmethyl and (S)-lactate were identified as suitable replacements for the alpha(2-->6)-linked sialic acid. Combined with a core modification and the earlier found aryl amide substituent in the 9-position of the alpha(2-->3)-linked sialic acid, high affinity MAG antagonists were identified. All mimics were tested in a competitive target-based binding assay, providing relative inhibitory potencies (rIP). Compared to the reference tetrasaccharide 1, the rIPs of the most potent antagonists 59 and 60 are enhanced nearly 400-fold. Their K(D)s determined in surface plasmon resonance experiments are in the low micromolar range. These results are in semiquantitative agreement with molecular modeling studies. This new class of glycomimetics will allow to validate the role of MAG in the axon regeneration process.

  11. GPU-Accelerated Denoising in 3D (GD3D)

    SciTech Connect

    2013-10-01

    The raw computational power GPU Accelerators enables fast denoising of 3D MR images using bilateral filtering, anisotropic diffusion, and non-local means. This software addresses two facets of this promising application: what tuning is necessary to achieve optimal performance on a modern GPU? And what parameters yield the best denoising results in practice? To answer the first question, the software performs an autotuning step to empirically determine optimal memory blocking on the GPU. To answer the second, it performs a sweep of algorithm parameters to determine the combination that best reduces the mean squared error relative to a noiseless reference image.

  12. Luminescence and magnetic properties of novel nanoparticle-sheathed 3D Micro-Architectures of Fe0.5R0.5(MoO4)1.5:Ln3+ (R = Gd3+, La3+), (Ln = Eu, Tb, Dy) for bifunctional application

    NASA Astrophysics Data System (ADS)

    Krishnan, Rajagopalan; Thirumalai, Jagannathan; Kathiravan, Arunkumar

    2015-01-01

    For the first time, we report the successful synthesis of novel nanoparticle-sheathed bipyramid-like and almond-like Fe0.5R0.5(MoO4)1.5:Ln3+ (R = Gd3+, La3+), (Ln = Eu, Tb, Dy) 3D hierarchical microstructures through a simple disodium ethylenediaminetetraacetic acid (Na2EDTA) facilitated hydrothermal method. Interestingly, time-dependent experiments confirm that the assembly-disassembly process is responsible for the formation of self-aggregated 3D architectures via Ostwald ripening phenomena. The resultant products are characterized by x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), photoluminescence (PL), and magnetic measurements. The growth and formation mechanisms of the self-assembled 3D micro structures are discussed in detail. To confirm the presence of all the elements in the microstructure, the energy loss induced by the K, L shell electron ionization is observed in order to map the Fe, Gd, Mo, O, and Eu components. The photo luminescence properties of Fe0.5R0.5(MoO4)1.5 doped with Eu3+, Tb3+, Dy3+ are investigated. The room temperature and low temperature magnetic properties suggest that the interaction between the local-fields introduced by the magnetic Fe3+ ions and the R3+ (La, Gd) ions in the dodecahedral sites determine the magnetism in Fe0.5R0.5(MoO4)1.5:Eu3+. This work provides a new approach to synthesizing the novel Fe0.5R0.5(MoO4)1.5:Ln3+ for bi-functional magnetic and luminescence applications.

  13. Binding Cooperativity Matters: A GM1-Like Ganglioside-Cholera Toxin B Subunit Binding Study Using a Nanocube-Based Lipid Bilayer Array

    PubMed Central

    Weatherston, Joshua D.

    2016-01-01

    Protein-glycan recognition is often mediated by multivalent binding. These multivalent bindings can be further complicated by cooperative interactions between glycans and individual glycan binding subunits. Here we have demonstrated a nanocube-based lipid bilayer array capable of quantitatively elucidating binding dissociation constants, maximum binding capacity, and binding cooperativity in a high-throughput format. Taking cholera toxin B subunit (CTB) as a model cooperativity system, we studied both GM1 and GM1-like gangliosides binding to CTB. We confirmed the previously observed CTB-GM1 positive cooperativity. Surprisingly, we demonstrated fucosyl-GM1 has approximately 7 times higher CTB binding capacity than GM1. In order to explain this phenomenon, we hypothesized that the reduced binding cooperativity of fucosyl-GM1 caused the increased binding capacity. This was unintuitive, as GM1 exhibited higher binding avidity (16 times lower dissociation constant). We confirmed the hypothesis using a theoretical stepwise binding model of CTB. Moreover, by taking a mixture of fucosyl-GM1 and GM2, we observed the mild binding avidity fucosyl-GM1 activated GM2 receptors enhancing the binding capacity of the lipid bilayer surface. This was unexpected as GM2 receptors have negligible binding avidity in pure GM2 bilayers. These unexpected discoveries demonstrate the importance of binding cooperativity in multivalent binding mechanisms. Thus, quantitative analysis of multivalent protein-glycan interactions in heterogeneous glycan systems is of critical importance. Our user-friendly, robust, and high-throughput nanocube-based lipid bilayer array offers an attractive method for dissecting these complex mechanisms. PMID:27070150

  14. Immunization with a mimotope of GD2 ganglioside induces CD8+ T cells that recognize cell adhesion molecules on tumor cells.

    PubMed

    Wierzbicki, Andrzej; Gil, Margaret; Ciesielski, Michael; Fenstermaker, Robert A; Kaneko, Yutaro; Rokita, Hanna; Lau, Joseph T; Kozbor, Danuta

    2008-11-01

    The GD2 ganglioside expressed on neuroectodermal tumor cells has been used as a target for passive and active immunotherapy in patients with malignant melanoma and neuroblastoma. We have reported that immunization of mice with a 47-LDA mimotope of GD2, isolated from a phage display peptide library with anti-GD2 mAb 14G2a, induces MHC class I-restricted CD8(+) T cell responses to syngeneic neuroblastoma tumor cells. The cytotoxic activity of the vaccine-induced CTLs was independent of GD2 expression, suggesting recognition of a novel tumor-associated Ag cross-reacting with 47-LDA. Glycan microarray and immunoblotting studies using 14G2a mAb demonstrated that this Ab is highly specific for the entire carbohydrate motif of GD2 but also cross-reacts with a 105 kDa glycoprotein expressed by GD2(+) and GD2(-) neuroblastoma and melanoma cells. Functional studies of tumor cells grown in three-dimensional collagen cultures with 14G2a mAb showed decreases in matrix metalloproteinase-2 activation, a process regulated by the 105 kDa-activated leukocyte cell adhesion molecule (ALCAM/CD166). A recombinant CD166 glycoprotein was shown to be recognized by 14G2a Ab and inhibition of CD166 expression by RNA interference ablated the cell sensitivity to lysis by 47-LDA-induced CD8(+) T cells in vitro and in vivo. The binding of 14G2a to CD166 was not disruptable by a variety of exo- and endo-glycosidases, implying recognition of a non-glycan epitope on CD166. These results suggest that the vaccine-induced CTLs recognize a 47-LDA cross-reactive epitope expressed by CD166, and reveal a novel mechanism of induction of potent tumor-specific cellular responses by mimotopes of tumor-associated carbohydrate Ags.

  15. Inefficiency in GM2 ganglioside elimination by human lysosomal beta-hexosaminidase beta-subunit gene transfer to fibroblastic cell line derived from Sandhoff disease model mice.

    PubMed

    Itakura, Tomohiro; Kuroki, Aya; Ishibashi, Yasuhiro; Tsuji, Daisuke; Kawashita, Eri; Higashine, Yukari; Sakuraba, Hitoshi; Yamanaka, Shoji; Itoh, Kohji

    2006-08-01

    Sandhoff disease (SD) is an autosomal recessive GM2 gangliosidosis caused by the defect of lysosomal beta-hexosaminidase (Hex) beta-subunit gene associated with neurosomatic manifestations. Therapeutic effects of Hex subunit gene transduction have been examined on Sandhoff disease model mice (SD mice) produced by the allelic disruption of Hexb gene encoding the murine beta-subunit. We demonstrate here that elimination of GM2 ganglioside (GM2) accumulated in the fibroblastic cell line derived from SD mice (FSD) did not occur when the HEXB gene only was transfected. In contrast, a significant increase in the HexB (betabeta homodimer) activity toward neutral substrates, including GA2 (asialo-GM2) and oligosaccharides carrying the terminal N-acetylglucosamine residues at their non-reducing ends (GlcNAc-oligosaccharides) was observed. Immunoblotting with anti-human HexA (alphabeta heterodimer) serum after native polyacrylamide gel electrophoresis (Native-PAGE) revealed that the human HEXB gene product could hardly form the chimeric HexA through associating with the murine alpha-subunit. However, co-introduction of the HEXA encoding the human alpha-subunit and HEXB genes caused significant corrective effect on the GM2 degradation by producing the human HexA. These results indicate that the recombinant human HexA could interspeciesly associate with the murine GM2 activator protein to degrade GM2 accumulated in the FSD cells. Thus, therapeutic effects of the recombinant human HexA isozyme but not human HEXB gene product could be evaluated by using the SD mice.

  16. Endocytosis of cholera toxin in GERL-like structures of murine neuroblastoma cells pretreated with GM1 ganglioside. Cholera toxin internalization into Neuroblastoma GERL

    PubMed Central

    1979-01-01

    Cholera toxin (CT), covalently attached to horseradish peroxidase (HRP), is a specific cytochemical marker for GM1 ganglioside (GM1) and retains the ability of the native toxin to raise levels of cyclic AMP in avian erythrocytes. Using a cytochemical stain for HRP, we found that 9% of control cultured murine neuroblastoma cells bound cholera toxin-horseradish peroxidase conjugates (CT-HRP) on their surfaces after incubations for 1 h at 4 degrees C. Exogenous GM1, the natural receptor of CT, becomes associated in the culture medium with the plasma membranes of these cells so that 96% of cells are stained. Cells preincubated with GM1 at 4 degrees C were exposed to CT-HRP for 1 h at 4 degrees C. After washing, cells were incubated at 37 degrees C for 30 min-24 h. Endocytosis of CT-HRP occurred within 30 min and CT-HRP remained, throughout the 24-h period, in tubules, vesicles, and cisternae often found near the Golgi apparatus; this aggregate of peroxidase-positive elements probably corresponds to Golgi apparatus- endoplasmic reticulum-lysosomes (GERL) of neurons. In metaphase cells, CT-HRP was observed in aggregates of vesicles and tubules clustered near the centriole. Conjugates of HRP with subunit B, the GM1 binding component of CT, were internalized by cells pretreated with GM1 as was CT-HRP. The 9% of neuroblastoma cells binding CT-HRP in the absence of exogenous GM1 internalized the ligand in a manner indistinguishable from that of the treated cells. These findings indicate that, in neuroblastoma cells, a system of vesicles, tubules, and cisternae, analogous to GERL of neurons, is the primary recipient of adsorptive endocytosis of CT bound to endogenous or exogenously introduced GM1. PMID:457774

  17. Modulation of interactions of neuroblastoma cell lines with extracellular matrix proteins affects their sensitivity to treatment with the anti-GD2 ganglioside antibody 14G2a.

    PubMed

    Horwacik, Irena; Rokita, Hanna

    2017-05-01

    Children diagnosed with high risk neuroblastoma have poor prognosis which stimulates efforts to broaden therapies of the neoplasm. GD2-ganglioside (GD2) marks neuroblastoma cells and is a target for monoclonal antibodies. We have recently shown that some neuroblastoma cell lines are sensitive to direct cytotoxicity of the anti-GD2 mouse monoclonal antibody 14G2a (mAb). For IMR-32 and LA-N-1 cell lines, treatment with the 14G2a mAb induced evident changes in appearance such as cell rounding, aggregation, loose contact with culture plastic, or detachment. Such findings prompted us to investigate whether modulation of attachment of neuroblastoma cells to extracellular matrix (ECM) proteins can affect their sensitivity to the 14G2a mAb treatment. First, using ultra-low attachment plates, we show that survival of the IMR-32, LA-N-1, LA-N-5, CHP-134 and Kelly cells depends on attachment. Next, we compared cellular ATP levels of the cell lines treated with the 14G2a mAb using uncoated, fibronectin-, collagen IV-coated surfaces to show that the ECM proteins slightly modulate sensitivity of the cell lines to the mAb. Then, we characterized presence of selected integrin subunits or their complexes on the cell surface. Finally, we applied small molecule inhibitors of selected integrin complexes: obtustatin (inhibiting α1β1 heterodimer), BIO 1211 (inhibiting active α4β1 heterodimer), cilengitide and SB273005 (inhibitors of αVβ3, αVβ5 heterodimers) to verify their effects on attachment of cell lines, cellular ATP levels, and in some experiments activities of apoptosis-executing caspase-3 and -7, for the compounds used alone or in combination with the 14G2a mAb. We characterized levels of total FAK (focal adhesion kinase), p-FAK (Tyr397) in IMR-32 cells treated with BIO 1211, and in LA-N-5, Kelly and SK-N-SH cells treated with SB273005. Our results extend knowledge on factors influencing cytotoxicity of 14G2a.

  18. A single native ganglioside GM1-binding site is sufficient for cholera toxin to bind to cells and complete the intoxication pathway.

    PubMed

    Jobling, Michael G; Yang, Zhijie; Kam, Wendy R; Lencer, Wayne I; Holmes, Randall K

    2012-10-30

    Cholera toxin (CT) from Vibrio cholerae is responsible for the majority of the symptoms of the diarrheal disease cholera. CT is a heterohexameric protein complex with a 240-residue A subunit and a pentameric B subunit of identical 103-residue B polypeptides. The A subunit is proteolytically cleaved within a disulfide-linked loop to generate the A1 and A2 fragments. The B subunit of wild-type (wt) CT binds 5 cell surface ganglioside GM(1) (GM(1)) molecules, and the toxin-GM(1) complex traffics from the plasma membrane (PM) retrograde through endosomes and the Golgi apparatus to the endoplasmic reticulum (ER). From the ER, the enzymatic A1 fragment retrotranslocates to the cytosol to cause disease. Clustering of GM(1) by multivalent toxin binding can structurally remodel cell membranes in ways that may assist toxin uptake and retrograde trafficking. We have recently found, however, that CT may traffic from the PM to the ER by exploiting an endogenous glycosphingolipid pathway (A. A. Wolf et al., Infect. Immun. 76:1476-1484, 2008, and D. J. F. Chinnapen et al., Dev. Cell 23:573-586, 2012), suggesting that multivalent binding to GM(1) is dispensable. Here we formally tested this idea by creating homogenous chimeric holotoxins with defined numbers of native GM(1) binding sites from zero (nonbinding) to five (wild type). We found that a single GM(1) binding site is sufficient for activity of the holotoxin. Therefore, remodeling of cell membranes by mechanisms that involve multivalent binding of toxin to GM(1) receptors is not essential for toxicity of CT. Through multivalent binding to its lipid receptor, cholera toxin (CT) can remodel cell membranes in ways that may assist host cell invasion. We recently found that CT variants which bind no more than 2 receptor molecules do exhibit toxicity, suggesting that CT may be able to enter cells by coopting an endogenous lipid sorting pathway without clustering receptors. We tested this idea directly by using purified variants

  19. Application study of 1,2-α-l-fucosynthase: introduction of Fucα1-2Gal disaccharide structures on N-glycan, ganglioside, and xyloglucan oligosaccharide.

    PubMed

    Sugiyama, Yuta; Katoh, Toshihiko; Honda, Yuji; Gotoh, Aina; Ashida, Hisashi; Kurihara, Shin; Yamamoto, Kenji; Katayama, Takane

    2017-02-01

    We have recently generated a highly efficient 1,2-α-l-fucosynthase (BbAfcA N423H mutant) by protein engineering of 1,2-α-l-fucosidase from Bifidobacterium bifidum JCM 1254. This synthase could specifically introduce H-antigens (Fucα1-2Gal) into the non-reducing ends of oligosaccharides and in O-linked glycans in mucin glycoprotein. In the present study, we show an extended application of the engineered 1,2-α-l-fucosynthase by demonstrating its ability to insert Fuc residues into N- and O-glycans in fetuin glycoproteins, GM1 ganglioside, and a plant-derived xyloglucan nonasaccharide. This application study broadens the feasibility of this novel H-antigen synthesis technique in functional glycomics.

  20. Growth inhibition of human lung adenocarcinoma cells by antibodies against epidermal growth factor receptor and by ganglioside GM3: involvement of receptor-directed protein tyrosine phosphatase(s).

    PubMed

    Suarez Pestana, E; Greiser, U; Sánchez, B; Fernández, L E; Lage, A; Perez, R; Böhmer, F D

    1997-01-01

    Growth of the EGF receptor-expressing non-small-cell lung carcinoma cell line H125 seems to be at least partially driven by autocrine activation of the resident EGF receptors. Thus, the possibility of an EGF receptor-directed antiproliferative treatment was investigated in vitro using a monoclonal antibody (alpha EGFR ior egf/r3) against the human EGF receptor and gangliosides which are known to possess antiproliferative and anti-tyrosine kinase activity. The moderate growth-inhibitory effect of alpha EGFR ior egf/r3 was strongly potentiated by the addition of monosialoganglioside GM3. Likewise, the combination of alpha EGFR ior egf/r3 and GM3 inhibited EGF receptor autophosphorylation activity in H125 cells more strongly than either agent alone. A synergistic inhibition of EGF receptor autophosphorylation by alpha EGFR ior egf/r3 and GM3 was also observed in the human epidermoid carcinoma cell line A431. In both cell lines, the inhibition of EGF receptor autophosphorylation by GM3 was prevented by pretreatment of the cells with pervanadate, a potent inhibitor of protein tyrosine phosphatases (PTPases). Also, GM3 accelerated EGF receptor dephosphorylation in isolated A431 cell membranes. These findings indicate that GM3 has the capacity to activate EGF receptor-directed PTPase activity and suggest a novel possible mechanism for the regulation of cellular PTPases.

  1. Growth inhibition of human lung adenocarcinoma cells by antibodies against epidermal growth factor receptor and by ganglioside GM3: involvement of receptor-directed protein tyrosine phosphatase(s).

    PubMed Central

    Suarez Pestana, E.; Greiser, U.; Sánchez, B.; Fernández, L. E.; Lage, A.; Perez, R.; Böhmer, F. D.

    1997-01-01

    Growth of the EGF receptor-expressing non-small-cell lung carcinoma cell line H125 seems to be at least partially driven by autocrine activation of the resident EGF receptors. Thus, the possibility of an EGF receptor-directed antiproliferative treatment was investigated in vitro using a monoclonal antibody (alpha EGFR ior egf/r3) against the human EGF receptor and gangliosides which are known to possess antiproliferative and anti-tyrosine kinase activity. The moderate growth-inhibitory effect of alpha EGFR ior egf/r3 was strongly potentiated by the addition of monosialoganglioside GM3. Likewise, the combination of alpha EGFR ior egf/r3 and GM3 inhibited EGF receptor autophosphorylation activity in H125 cells more strongly than either agent alone. A synergistic inhibition of EGF receptor autophosphorylation by alpha EGFR ior egf/r3 and GM3 was also observed in the human epidermoid carcinoma cell line A431. In both cell lines, the inhibition of EGF receptor autophosphorylation by GM3 was prevented by pretreatment of the cells with pervanadate, a potent inhibitor of protein tyrosine phosphatases (PTPases). Also, GM3 accelerated EGF receptor dephosphorylation in isolated A431 cell membranes. These findings indicate that GM3 has the capacity to activate EGF receptor-directed PTPase activity and suggest a novel possible mechanism for the regulation of cellular PTPases. Images Figure 5 Figure 6 PMID:9010029

  2. Novel Anti-idiotype Antibody Therapy for Lipooligosaccharide-Induced Experimental Autoimmune Neuritis: Use Relevant to Guillain-Barré Syndrome

    PubMed Central

    Usuki, S.; Taguchi, K.; Thompson, S.A.; Chapman, P.B.; Yu, R.K.

    2010-01-01

    Campylobacteriosis is a frequent antecedent event in Guillain-Barré syndrome (GBS), inducing high-titer serum antibodies for ganglioside antigens in the peripheral nervous system (PNS). Molecular mimicry between the lipooligosaccharide (LOS) component of Campylobacter jejuni and human peripheral nerve gangliosides is believed to play an important role in the pathogenesis of GBS. Conventional treatment strategies for patients with GBS include plasmapheresis, intravenous immunoglobulin (IVIG), and immunosuppression, which are invasive or relatively ineffective. In this study, we used our animal model of GBS, in which Lewis rats were immunized with GD3-like LOS isolated from C. jejuni. The animals developed anti-GD3 ganglioside antibodies and manifested neuromuscular dysfunction. To develop novel therapeutic strategies, we treated the animals by intraperitoneal administration of an anti-GD3 antiidiotype monoclonal antibody (BEC2) that specifically interacts with the pathogenic antibody. The treated animals had a remarkable reduction of anti-GD3 antibody titers and improvement of motor nerve functions. The results suggest that ganglioside mimics, such as antiidiotype antibodies, may be powerful reagents for therapeutic intervention in GBS by neutralizing specific pathogenic antiganglioside antibodies. PMID:20077429

  3. Preparation and characterization of [Gd(hfac)3(DTBN)(H2O)] (DTBN = di-t-butyl nitroxide). Ferromagnetic Gd(3+)-Gd3+ super-superexchange.

    PubMed

    Kanetomo, Takuya; Ishida, Takayuki

    2014-03-07

    The intramolecular radical-Gd antiferromagnetic coupling (2J1/k(B) = -11.6 K) is notably strong, as expected from our molecular design, and the intermolecular exchange coupling along the Gd-O-H···O-Gd bridges is unexpectedly ferromagnetic with the largest Gd···Gd coupling ever known (2J2/k(B) = +0.12 K).

  4. Differential Anatomical Expression of Ganglioside GM1 Species Containing d18:1 or d20:1 Sphingosine Detected by MALDI Imaging Mass Spectrometry in Mature Rat Brain

    PubMed Central

    Weishaupt, Nina; Caughlin, Sarah; Yeung, Ken K.-C.; Whitehead, Shawn N.

    2015-01-01

    GM1 ganglioside plays a role in essential neuronal processes, including differentiation, survival, and signaling. Yet, little is known about GM1 species with different sphingosine bases, such as the most abundant species containing 18 carbon atoms in the sphingosine chain (GM1d18:1), and the less abundant containing 20 carbon atoms (GM1d20:1). While absent in the early fetal brain, GM1d20:1 continues to increase throughout pre- and postnatal development and into old age, raising questions about the functional relevance of the GM1d18:1 to GM1d20:1 ratio. Matrix-assisted laser desorption/ionization imaging mass spectrometry is a novel technology that allows differentiation between these two GM1 species and quantification of their expression within an anatomical context. Using this technology, we find GM1d18:1/d20:1 expression ratios are highly specific to defined anatomical brain regions in adult rats. Thus, the ratio was significantly different among different thalamic nuclei and between the corpus callosum and internal capsule. Differential GM1d18:1/GM1d20:1 ratios measured in hippocampal subregions in rat brain complement previous studies conducted in mice. Across layers of the sensory cortex, opposing expression gradients were found for GM1d18:1 and GM1d20:1. Superficial layers demonstrated lower GM1d18:1 and higher GM1d20:1 signal than other layers, while in deep layers GM1d18:1 expression was relatively high and GM1d20:1 expression low. By far the highest GM1d18:1/d20:1 ratio was found in the amygdala. Differential expression of GM1 with d18:1- or d20:1-sphingosine bases in the adult rat brain suggests tight regulation of expression and points toward a distinct functional relevance for each of these GM1 species in neuronal processes. PMID:26648849

  5. Endogenous glycosphingolipid acceptor specificity of sialosyltransferase systems in intact golgi membranes, synaptosomes, and synaptic plasma membranes from rat brain

    SciTech Connect

    Durrie, R.; Saito, M.; Rosenberg, A.

    1988-05-17

    Preparations highly enriched in Golgi complex membranes, synaptosomes, and synaptic plasma membranes (SPM) by marker enzyme analysis and electron microscopic morphology were made from the brains of 28-day-old rats. These were incubated with cytidine 5'-monophosphate-N-acetyl(/sup 14/C)neuraminic acid (CMP-NeuAc) in a physiologic buffer, without detergents. Glycolipid sialosyltransferase activities (SATs) were measured by analyzing incorporation of radiolabeled NeuAc into endogenous membrane gangliosides. Golgi SAT was diversified in producing all the various molecular species of labeled gangliosides. Synaptosomal SAT exhibited a lower activity, but it was highly specific in its labeling pattern, with a marked preference for labeling NeuAc..cap alpha..2 ..-->.. 8NeuAc..cap alpha..2 ..-->.. 3Gal..beta..1 ..-->.. 4Glc..beta..1 ..-->.. 1Cer (GD3 ganglioside). SPM prepared from the synaptosomes retained the GD3-related SAT (or SAT-2), and the total specific activity increased, which suggests that the location of the synaptosomal activity is in the SPM. These results indicate that SAT activity in Golgi membranes differs from that in synaptosomes with regard to endogenous acceptor substrate specificity and SAT activity of synaptosomes should be located in the synaptosomal plasma membrane. This SAT could function as an ectoenzyme in concert with ecto-sialidase to modulate the GD3 and other ganglioside population in situ at the SPM of the central nervous system.

  6. Materials Data on Gd3OsO7 (SG:63) by Materials Project

    DOE Data Explorer

    Kristin Persson

    2016-02-10

    Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

  7. Materials Data on Gd3CuSnS7 (SG:173) by Materials Project

    SciTech Connect

    Kristin Persson

    2014-07-09

    Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

  8. Materials Data on Gd3CuGeS7 (SG:173) by Materials Project

    SciTech Connect

    Kristin Persson

    2014-07-09

    Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

  9. Materials Data on Gd3Co11B4 (SG:191) by Materials Project

    SciTech Connect

    Kristin Persson

    2014-07-09

    Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

  10. Materials Data on Gd3Ni19B10 (SG:12) by Materials Project

    DOE Data Explorer

    Kristin Persson

    2016-02-04

    Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

  11. Materials Data on Gd3CCl3 (SG:214) by Materials Project

    SciTech Connect

    Kristin Persson

    2016-02-05

    Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

  12. Materials Data on Gd3B2(O2F)3 (SG:15) by Materials Project

    SciTech Connect

    Kristin Persson

    2014-07-09

    Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

  13. Materials Data on Gd3Pd2 (SG:127) by Materials Project

    SciTech Connect

    Kristin Persson

    2014-11-02

    Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

  14. [Genetic information from tumor-infiltrating B lymphocytes as a driver tool ("GPS") for anti-tumor T cell CARs].

    PubMed

    Kotlan, Beatrix; Csuka, Orsolya; Tóth, László; Farkas, Emil; Plótár, Vanda; Horváth, Szabolcs; Éles, Klára; Olasz, Judit; Tóth, József; Kásler, Miklós; Liszkay, Gabriella

    2016-03-02

    The rapidly growing field of gene therapy techniques to modify T cells with chimeric antigen receptors (CARs) for cancer care solutions, reached considerable achievements. However, there is an urgent need of reliable, well tolerable tumor-associated antigen specific antibodies. Tumor-infiltrating B (TIL-B) cell originated single chain Fv (scFv) gene regions could be selected with tumor specificity. DNA sequences of these antibody variable regions were subjects to get engineered into new CAR constructs. Our novel strategy harnesses tumor-infiltrating B cells' unique capacity to reveal highly tumor-associated disialylated glycosphingolipids (GD3 gangliosides). We used these human antibody fragments for generating GD3 ganglioside specific CAR gene constructs for potential usage in solid tumors.

  15. Biosignals modulated by tumor-associated carbohydrate antigens: novel targets for cancer therapy.

    PubMed

    Furukawa, Koichi; Hamamura, Kazunori; Aixinjueluo, Wei; Furukawa, Keiko

    2006-11-01

    Based on the remodeling of glycosphingolipids on the human tumor cell lines with manipulation of glycosyltransferase genes, roles of sugar moieties in tumor-associated carbohydrate antigens have been analyzed. Two main topics, that is, the roles of ganglioside GD3 in human malignant melanomas and those of GD2 in small cell lung cancer (SCLC) were reported. GD3 enhances tyrosine phosphorylation of two adaptor molecules, p130Cas and paxillin, resulting in the increased cell growth and invasion in melanoma cells. GD2 also enhances the proliferation and invasion of SCLC cells. GD2 also mediates apoptosis with anti-GD2 monoclonal antibodies (mAbs) via dephosphorylation of the focal adhesion kinase. These approaches have promoted further understanding of mechanisms by which gangliosides modulate malignant properties of human cancer, and the results obtained here propose novel targets for cancer therapy.

  16. Microwave-assisted synthesis of Gd3+ doped PbI2 hierarchical nanostructures for optoelectronic and radiation detection applications

    NASA Astrophysics Data System (ADS)

    Shkir, Mohd.; AlFaify, S.; Yahia, I. S.; Ganesh, V.; Shoukry, H.

    2017-03-01

    In this work, we report the simple, low temperature and rapid microwave-assisted synthesis of undoped and Gadolinium (III) doped lead iodide with different morphologies, i.e. nanorods of average diameter 200 nm and hierarchical (flower-shaped) nanosheets of thicknesses less than 100 nm. Prepared nanostructures were typify in details using a variety of analytical techniques that reveal the well crystallinity with hexagonal structure. We found that by changing the concentrations of Gadolinium (III) one can tailor the size and shape of nanostructures of lead iodide. The presence of Gadolinium (III) doping was assessed by energy dispersive X-ray analysis. Optical band gap and Photoluminescence intensity are found to be enhanced due to Gadolinium (III) doping. The value of Gamma linear absorption coefficient is found to be enriched with doping, which suggests its application in radiation detection.

  17. Gd(3+)-Yb(3+) Exchange Interactions in LiYb(x)Y(1-x)F4 Single Crystals

    DTIC Science & Technology

    2001-01-01

    fluorolanthanate phases," Inorg. Chem. 9, pp. 1096-1101, 1970. 6. L. E. Misiak, P. Mikolajczak and M. Subotowicz, "Lithium rare-earth fluoride crystal growth and...of Gd 34 in LiYF 4 determined by EPR," Solid State Commun. 45, pp. 1093-1098, 1983. 8. S. K. Misra, M. Kahrizi, P. Mikolajczak and L. E. Misiak, "EPR...and P. Mikolajczak , "EPR of Gd34 -doped single crystals of LiYbxY_,-F 4," Phys. Rev. B 38, pp. 8673-8682, 1988. 10. M. R. St. John and R. J. Myers

  18. Evidence for the involvement of lipid rafts localized at the ER-mitochondria associated membranes in autophagosome formation.

    PubMed

    Garofalo, Tina; Matarrese, Paola; Manganelli, Valeria; Marconi, Matteo; Tinari, Antonella; Gambardella, Lucrezia; Faggioni, Alberto; Misasi, Roberta; Sorice, Maurizio; Malorni, Walter

    2016-06-02

    Mitochondria-associated membranes (MAMs) are subdomains of the endoplasmic reticulum (ER) that interact with mitochondria. This membrane scrambling between ER and mitochondria appears to play a critical role in the earliest steps of autophagy. Recently, lipid microdomains, i.e. lipid rafts, have been identified as further actors of the autophagic process. In the present work, a series of biochemical and molecular analyses has been carried out in human fibroblasts with the specific aim of characterizing lipid rafts in MAMs and to decipher their possible implication in the autophagosome formation. In fact, the presence of lipid microdomains in MAMs has been detected and, in these structures, a molecular interaction of the ganglioside GD3, a paradigmatic "brick" of lipid rafts, with core-initiator proteins of autophagy, such as AMBRA1 and WIPI1, was revealed. This association seems thus to take place in the early phases of autophagic process in which MAMs have been hypothesized to play a key role. The functional activity of GD3 was suggested by the experiments carried out by knocking down ST8SIA1 gene expression, i.e., the synthase that leads to the ganglioside formation. This experimental condition results in fact in the impairment of the ER-mitochondria crosstalk and the subsequent hindering of autophagosome nucleation. We thus hypothesize that MAM raft-like microdomains could be pivotal in the initial organelle scrambling activity that finally leads to the formation of autophagosome.

  19. Crystal Field Study of Gd(3+)-Doped La(x)RE(1-x)F3 (RE=Ce,Pr,Nd) Single Crystals

    DTIC Science & Technology

    2001-01-01

    the vacuum ultraviolet:LalCeF 3 " Appl. Optics 12, pp. 138-139, 1973. 6. W. Korczak and P. Mikolajczak , "Crystal growth and temperature variation of...spin-phonon interactions and spin-lattice relaxations" Acta Phys. Pol. A 95, pp. 367-380, 1999. 12. L. E. Misiak, S. K. Misra and P. Mikolajczak

  20. Multifunctional Magnetic Gd(3+) -Based Coordination Polymer Nanoparticles: Combination of Magnetic Resonance and Multispectral Optoacoustic Detections for Tumor-Targeted Imaging in vivo.

    PubMed

    An, Qiao; Liu, Jing; Yu, Meng; Wan, Jiaxun; Li, Dian; Wang, Changchun; Chen, Chunying; Guo, Jia

    2015-11-11

    To overcome traditional barriers in optical imaging and microscopy, optoacoustic-imaging has been changed to combine the accuracy of spectroscopy with the depth resolution of ultrasound, achieving a novel modality with powerful in vivo imaging. However, magnetic resonance imaging provides better spatial and anatomical resolution. Thus, a single hybrid nanoprobe that allows for simultaneous multimodal imaging is significant not only for cutting edge research in imaging science, but also for accurate clinical diagnosis. A core-shell-structured coordination polymer composite microsphere has been designed for in vivo multimodality imaging. It consists of a Fe3 O4 nanocluster core, a carbon sandwiched layer, and a carbocyanine-Gd(III) (Cy-Gd(III) ) coordination polymer outer shell (Fe3 O4 @C@Cy-Gd(III) ). Folic acid-conjugated poly(ethylene glycol) chains are embedded within the coordination polymer shell to achieve extended circulation and targeted delivery of probe particles in vivo. Control of Fe3 O4 core grain sizes results in optimal r2 relaxivity (224.5 × 10(-3) m(-1) s(-1) ) for T2 -weighted magnetic resonance imaging. Cy-Gd(III) coordination polymers are also regulated to obtain a maximum 25.1% of Cy ligands and 5.2% of Gd(III) ions for near-infrared fluorescence and T1 -weighted magnetic resonance imaging, respectively. The results demonstrate their impressive abilities for targeted, multimodal, and reliable imaging.

  1. 5 d-4 f luminescence of Nd3+, Gd3+, Er3+, Tm3+, and Ho3+ ions in crystals of alkaline earth fluorides

    NASA Astrophysics Data System (ADS)

    Radzhabov, E. A.; Prosekina, E. A.

    2011-09-01

    The vacuum ultraviolet emission spectra of alkaline-earth fluoride (CaF2, SrF2, BaF2) crystals with rare earth impurity ions (Nd, Gd, Er, Tm, Ho) have been investigated. The main luminescence bands are described well by the transitions from the lowest excited 5 d state to different 4 f levels of rare earth ions.

  2. Luminescence (M=Mn2+, Cu2+) and Esr (M=Gd3+, Mn2+, Cu2+) of Na2ZnP2O7: M

    NASA Astrophysics Data System (ADS)

    Kumar, B. Vijaya; Vithal, M.

    2012-06-01

    We report the synthesis of sodium zinc diphosphate (Na2ZnP2O7) using a domestic microwave oven (2.45 GHz) and metal ion doped sodium zinc diphosphate (Na1.88Gd0.04ZnP2O7/Na1.92M0.04ZnP2O7 (M=Mn and Cu)) by a solid state metathesis reaction. All the materials were characterized by powder X-ray diffraction (XRD) and infrared spectroscopy (IR). These metal doped diphosphates were crystallized in a tetragonal lattice with space group P42/mnm. The IR spectra of all the samples were characterized by bands due to the P2O74- group. The powder electron spin resonance (ESR) spectrum of Na1.88Gd0.04ZnP2O7 gave a characteristic “U” type spectrum. The powder ESR spectrum of Na1.92Mn0.04ZnP2O7 consists of six lines while Na1.92Cu0.04ZnP2O7 gave a broad profile. All the doped metal ions occupy the Na+ site in the diphosphate lattice. The broad emission band at 614 nm (red band) observed for Na1.92Mn0.04ZnP2O7 is assigned to an electronic transition T14(G4)→A16(S6) of Mn2+ in distorted octahedral coordination.

  3. Magnetization dynamics in rare earth Gd3+ doped Mn(0.5)Zn(0.5)Fe2O4 magnetic fluid: electron spin resonance study.

    PubMed

    Parekh, Kinnari; Upadhyay, R V

    2012-12-01

    The electron spin resonance (ESR) technique has been applied to study the spin dynamics in broad temperature range for rare earth doped Mn(0.5)Zn(0.5)Fe(1.9)Gd(0.1)O(4) (MZG5) magnetic fluid. Zero field cooled (ZFC) ESR spectra of MZG5 fluid exhibit an isotropic shift in the resonance field below 40 K, while the field cooled (FC) ESR spectra show a deviation from sin(2)θ behavior and an angle dependent hysteresis, this unambiguously points to the dominating unidirectional freezing of surface spins below 40 K. Above 60 K, the resonance field exhibits sin(2)θ behavior, indicating the uniaxial anisotropy contribution of core spin. This indicates that surface spin freezing temperature is around 40 K. The presence of surface spin freezing and the coupling between core and surface spins are further supported by cycle dependent FC ESR spectra measured at 20 K, which show the systematic increase in resonance field (H(res)) and intensity. The double peak behavior of blocking temperature distribution retrieved from ZFC-FC magnetization measurement is an additional corroboration of the existence of surface spin glass like layer.

  4. Co-doping effects on luminescence and scintillation properties of Ce doped (Lu,Gd)3(Ga,Al)5O12 scintillator

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Hiroaki; Kamada, Kei; Kurosawa, Shunsuke; Pejchal, Jan; Shoji, Yasuhiro; Yokota, Yuui; Ohashi, Yuji; Yoshikawa, Akira

    2016-11-01

    Mg co-doping effects on scintillation properties of Ce:Lu1Gd2(Ga,Al)5O12 (LGGAG) were investigated. Mg 200 ppm co-doped Ce:LGGAG single crystals were prepared by micro pulling down method. Absorption and luminescence spectra were measured together with several other scintillation characteristics, namely the scintillation decay and light yield to reveal the effect of Mg co-doping. Ce4+ charge transfer absorption was observed below 300 nm in Mg,Ce:LGGAG which is in good agreement with previous reports. The scintillation decay times were accelerated by Mg co-doping.

  5. Serotype-specific differences in inhibition of reovirus infectivity by human-milk glycans are determined by viral attachment protein σ1.

    PubMed

    Iskarpatyoti, Jason A; Morse, E Ashley; McClung, R Paul; Ikizler, Miné; Wetzel, J Denise; Contractor, Nikhat; Dermody, Terence S

    2012-11-25

    Human milk contains many bioactive components, including secretory IgA, oligosaccharides, and milk-associated proteins. We assessed the antiviral effects of several components of milk against mammalian reoviruses. We found that glucocerebroside (GCB) inhibited the infectivity of reovirus strain type 1 Lang (T1L), whereas gangliosides GD3 and GM3 and 3'-sialyllactose (3SL) inhibited the infectivity of reovirus strain type 3 Dearing (T3D). Agglutination of erythrocytes mediated by T1L and T3D was inhibited by GD3, GM3, and bovine lactoferrin. Additionally, α-sialic acid, 3SL, 6'-sialyllactose, sialic acid, human lactoferrin, osteopontin, and α-lactalbumin inhibited hemagglutination mediated by T3D. Using single-gene reassortant viruses, we found that serotype-specific differences segregate with the gene encoding the viral attachment protein. Furthermore, GD3, GM3, and 3SL inhibit T3D infectivity by blocking binding to host cells, whereas GCB inhibits T1L infectivity post-attachment. These results enhance an understanding of reovirus cell attachment and define a mechanism for the antimicrobial activity of human milk.

  6. Microarray analysis of differentially expressed genes regulating lipid metabolism during melanoma progression.

    PubMed

    Sumantran, Venil N; Mishra, Pratik; Sudhakar, N

    2015-04-01

    A new hallmark of cancer involves acquisition of a lipogenic phenotype which promotes tumorigenesis. Little is known about lipid metabolism in melanomas. Therefore, we used BRB (Biometrics Research Branch) class comparison tool with multivariate analysis to identify differentially expressed genes in human cutaneous melanomas, compared with benign nevi and normal skin derived from the microarray dataset (GDS1375). The methods were validated by identifying known melanoma biomarkers (CITED1, FGFR2, PTPRF, LICAM, SPP1 and PHACTR1) in our results. Eighteen genes regulating metabolism of fatty acids, lipid second messengers and gangliosides were 2-9 fold upregulated in melanomas of GDS-1375. Out of the 18 genes, 13 were confirmed by KEGG pathway analysis and 10 were also significantly upregulated in human melanoma cell lines of NCI-60 Cell Miner database. Results showed that melanomas upregulated PPARGC1A transcription factor and its target genes regulating synthesis of fatty acids (SCD) and complex lipids (FABP3 and ACSL3). Melanoma also upregulated genes which prevented lipotoxicity (CPT2 and ACOT7) and regulated lipid second messengers, such as phosphatidic acid (AGPAT-4, PLD3) and inositol triphosphate (ITPKB, ITPR3). Genes for synthesis of pro-tumorigenic GM3 and GD3 gangliosides (UGCG, HEXA, ST3GAL5 and ST8SIA1) were also upregulated in melanoma. Overall, the microarray analysis of GDS-1375 dataset indicated that melanomas can become lipogenic by upregulating genes, leading to increase in fatty acid metabolism, metabolism of specific lipid second messengers, and ganglioside synthesis.

  7. Characterization of moose intestinal glycosphingolipids.

    PubMed

    Johansson, Miralda Madar; Dedic, Benjamin; Lundholm, Klara; Branzell, Filip Berner; Barone, Angela; Benktander, John; Teneberg, Susann

    2015-08-01

    As a part of a systematic investigation of the species-specific expression of glycosphingolipids, acid and non-acid glycosphingolipids were isolated from three small intestines and one large intestine of the moose (Alces alces). The glycosphingolipids were characterized by binding of monoclonal antibodies, lectins and bacteria in chromatogram binding assays, and by mass spectrometry. The non-acid fractions were complex mixtures, and all had glycosphingolipids belonging to the lacto- and neolactoseries (lactotriaosylceramide, lactotetraosylceramide, neolactotetraosylceramide, Galα3-Le(x) hexaosylceramide, and lacto-neolactohexaosylceramide), globo-series (globotriaosylceramide and globotetraosylceramide), and isogloboseries (isoglobotriaosylceramide). Penta- and heptaglycosylceramides with terminal Galili determinants were also characterized. Furthermore, glycosphingolipids with terminal blood group O determinants (H triaosylceramide, H type 2 pentaosylceramide, H type 1 penta- and heptaosylceramide) were characterized in two of the moose small intestines, and in the one large intestine, while the third small intestine had glycosphingolipids with terminal blood group A determinants (A tetraosylceramide, A type 1 hexa- and octaosylceramide, A dodecaosylceramide). The acid glycosphingolipid fractions of moose small and large intestine contained sulfatide, and the gangliosides GM3, GD3, GD1a, GD1b, and also NeuGc and NeuAc variants of the Sd(a) ganglioside and the sialyl-globopenta/SSEA-4 ganglioside. In humans, the NeuAc-globopenta/SSEA-4 ganglioside is a marker of embryonic and adult stem cells, and is also expressed in several human cancers. This is the first time sialyl-globopentaosylceramide/SSEA-4 has been characterized in a fully differentiated normal tissue, and also the first time NeuGc-globopentaosylceramide has been characterized.

  8. The mechanism of PDT-induced apoptosis

    NASA Astrophysics Data System (ADS)

    Cai, Xiongwei; Liu, Timon C.; Ding, Xin-Min; Gu, Ying; Liu, Fan-Guang; Liu, Song-Hao

    2003-12-01

    Photodynamic therapy (PDT) can induce apoptosis in many cancer cells in vitro and in tumors in vivo. Cells become more oxidation with PDT, and maintain differentiation and proliferation, go apoptosis and necrosis with the increase of reactive oxygen species (ROS) concentration. ROS can induce apoptosis through mitochondria by inhibiting respiration chain or oxidative phosphorylation or damaging mitochondrial membrane. ROS can initiate apoptosis through endoplamic reticulum(ER) by opening Ca2+ channel or starting unfold protein response (UPR). ROS can also induce apoptosis through Golgi by producing ganglioside GD3 by use of ceramide, which induces apoptosis by activating caspase-3, JNK and p38 MAPK. It can also induce apoptosis by activating Bip (mitochondria-dependant) or preocaspase-12 (mitochondria- independent) or inhibiting protein synthesizing. There are so complicated cross-talking among different signal pathways or organnells that we think PDT-induced apoptosis is mediated by multiplex pathways and excessive levels in a refined network.

  9. GM1 ganglioside reduces ethanol intoxication and the development of ethanol dependence.

    PubMed

    Wallis, C J; Rezazadeh, S M; Lal, H

    1995-01-01

    The monosialoganglioside, GM1, protects the nervous system against a variety of insults. In this study, we evaluated the protective properties of GM1 on ethanol intoxication and development of dependence. GM1 (20-40 mg/kg, IP) reduced the extent and duration of ataxia produced by ethanol (2 g/kg, IP, 15-95 min), and delayed the onset of loss and reduced the duration of the righting reflex (LORR) produced by ethanol (4.2 g/kg, IP). GM1 did not alter ethanol-induced hypothermia or the rate of ethanol clearance. Rather, GM1 increased the waking blood ethanol concentration. In animals fed a complete liquid diet containing 4.5% ethanol, concurrent administration of GM1 (40 mg/kg/day) blocked the tremors, hypolocomotion, and anxiety-like behavior associated with ethanol withdrawal. These findings demonstrate that GM1 reduces both ethanol's acute intoxication and the signs and symptoms of ethanol withdrawal by a mechanism not related to ethanol pharmacokinetics.

  10. Immunopotentiation of Mucosal Secretory IgA Responses by Use of a Ganglioside Binding Probe

    DTIC Science & Technology

    1984-09-25

    8217- products of which, when tested at high concentrations, retained a residual toxicity of undetermined nature. Since any contamination would adversely effect...were then tested for production of LT using the YJ adrenal cell system and an Enzyme Linked Immunosorbent Assay (ELISA). Subsequent analysis of pDF82...34, -- bND, None Detected when tested at 25,000 ng per well. -...-..--..--. -. .. .. .... .. The cloned LT-B DNA was recloned from pDF87 into the single

  11. Targeting and killing glioblastoma with monoclonal antibody to O-acetyl GD2 ganglioside

    PubMed Central

    Fougeray, Sophie; Oliver, Lisa; Geraldo, Fanny; Terme, Mickaël; Dorvillius, Mylène; Loussouarn, Delphine; Vallette, François; Paris, François; Birklé, Stéphane

    2016-01-01

    There are still unmet medical needs in the treatment of glioblastoma, the most common and the most aggressive glioma of all brain tumors. Here, we found that O-acetyl GD2 is expressed in surgically resected human glioblastoma tissue. In addition, we demonstrated that 8B6 monoclonal antibody specific for O-acetylat GD2 could effectively inhibit glioblastoma cell proliferation in vitro and in vivo. Taken together, these results indicate that O-acetylated GD2 represents a novel antigen for immunotherapeutic-based treatment of high-grade gliomas. PMID:27172791

  12. Radioimmune assay of ganglioside GM/sub 1/ synthase using cholera toxin

    SciTech Connect

    Honke, K.; Taniguchi, N.; Makita, A.

    1986-01-01

    A radioimmune assay for uridine 5'-diphosphate-galactose (UDP-Gal):GM/sub 2/ galactosyltransferase, which synthesizes GM/sub 1/, has been developed utilizing cholera toxin. This assay is more sensitive and simpler than previously used assays. Radioactive nucleotide substrate and GM/sub 2/ were incubated with an enzyme sample, and a radiolabeled product, GM/sub 1/, was reacted with cholera toxin. The GM/sub 1/-cholera toxin complex was further reacted with anti-cholera toxin and Staphylococcus aureus cell suspension. The resulting complex was transferred onto a nitrocellulose membrane and quantitated by liquid scintillation counting. This assay was found to be sensitive for the detection of 100 pmol of the reaction product, GM/sub 1/. With this assay method, some properties of the crude enzyme extracts from rat liver were studied. The enzyme had a pH optimum of 6.5-7.0 and required Mn/sup 2 +/. The K/sub m/ values for UDP-Gal and GM/sub 2/ were 0.12 mM and 6 ..mu..M, respectively.

  13. Nile Tilapia Neu3 sialidases: molecular cloning, functional characterization and expression in Oreochromis niloticus.

    PubMed

    Chigwechokha, Petros Kingstone; Komatsu, Masaharu; Itakura, Takao; Shiozaki, Kazuhiro

    2014-11-15

    Mammalian Neu3 is a ganglioside specific sialidase. Gangliosides are involved in various physiological events such as cell growth, differentiation and diseases. Significance of Neu3 and gangliosides is still unclear in aquaculture fish species. To gain more insights of fish Neu3 sialidases, molecular cloning and characterization were carried out in tilapia (Oreochromis niloticus). A tilapia genome-wide search for orthologues of human NEU1, NEU2, NEU3 and NEU4 yielded eight putative tilapia sialidases, five of which were neu3-like and designated as neu3a, neu3b, neu3c, neu3d and neu3e. Among five neu3 genes, neu3a, neu3d and neu3e were amplified by PCR from adult fish brain cDNA with consensus sequences of 1227bp, 1194bp and 1155bp, respectively. Multiple alignments showed conserved three Asp-boxes (SXDXGXTW), YRIP and VGPG motifs. The molecular weights for Neu3a, Neu3d and Neu3e were confirmed using immunoblotting analysis as 45.9kDa, 44.4kDa and 43.6kDa, respectively. Lysate from neu3 genes transfected HEK293 cells showed sialidase activity in Neu3a towards ganglioside mix optimally at pH4.6. Using pure gangliosides as substrates, highest sialidase activity for Neu3a was observed towards GD3 followed by GD1a and GM3, but not GM1. On the other hand, sialidase activities were not observed in Neu3d and Neu3e towards various sialoglycoconjugates. Indirect immunofluorescence showed that tilapia Neu3a and Neu3d are localized at the plasma membrane, while most Neu3e showed a cytosolic localization. RT-PCR analyses for neu3a showed significant expression in the brain, liver, and spleen tissues, while neu3d and neu3e showed different expression patterns. Based on these results, tilapia Neu3 exploration is an important step towards full understanding of a more comprehensive picture of Neu3 sub-family of proteins in fish.

  14. Lipooligosaccharide of Campylobacter jejuni

    PubMed Central

    Houliston, R. Scott; Vinogradov, Evgeny; Dzieciatkowska, Monika; Li, Jianjun; St. Michael, Frank; Karwaski, Marie-France; Brochu, Denis; Jarrell, Harold C.; Parker, Craig T.; Yuki, Nobuhiro; Mandrell, Robert E.; Gilbert, Michel

    2011-01-01

    Campylobacter jejuni is well known for synthesizing ganglioside mimics within the glycan component of its lipooligosaccharide (LOS), which have been implicated in triggering Guillain-Barré syndrome. We now confirm that this pathogen is capable of synthesizing a much broader spectrum of host glycolipid/glycoprotein mimics within its LOS. P blood group and paragloboside (lacto-N-neotetraose) antigen mimicry is exhibited by RM1221, a strain isolated from a poultry source. RM1503, a gastroenteritis-associated strain, expresses lacto-N-biose and sialyl-Lewis c units, the latter known as the pancreatic tumor-associated antigen, DU-PAN-2 (or LSTa). C. jejuni GC149, a Guillain-Barré syndrome-associated strain, expresses an unusual sialic acid-containing hybrid oligosaccharide with similarity to both ganglio and Pk antigens and can, through phase variation of its LOS biosynthesis genes, display GT1a or GD3 ganglioside mimics. We show that the sialyltransferase CstII and the galactosyltransferase CgtD are involved in the synthesis of multiple mimic types, with LOS structural diversity achieved through evolving allelic substrate specificity. PMID:21257763

  15. MALDI imaging delineates hippocampal glycosphingolipid changes associated with neurotoxin induced proteopathy following neonatal BMAA exposure.

    PubMed

    Karlsson, Oskar; Michno, Wojciech; Ransome, Yusuf; Hanrieder, Jörg

    2016-12-09

    The environmental toxin β-N-methylamino-L-alanine (BMAA) has been proposed to contribute to neurodegenerative diseases. We have previously shown that neonatal exposure to BMAA results in dose-dependent cognitive impairments, proteomic alterations and progressive neurodegeneration in the hippocampus of adult rats. A high BMAA dose (460mg/kg) also induced intracellular fibril formation, increased protein ubiquitination and enrichment of proteins important for lipid transport and metabolism. The aim of this study was therefore to elucidate the role of neuronal lipids in BMAA-induced neurodegeneration. By using matrix assisted laser desorption/ionization imaging mass spectrometry (MALDI IMS), we characterized the spatial lipid profile in the hippocampus of six month-old rats that were treated neonatally (postnatal days 9-10) with 460mg/kg BMAA. Multivariate statistical analysis revealed long-term changes in distinct ganglioside species (GM, GD, GT) in the dentate gyrus. These changes could be a consequence of direct effects on ganglioside biosynthesis through the b-series (GM3-GD3-GD2-GD1b-GT1b) and may be linked to astrogliosis. Complementary immunohistochemistry experiments towards GFAP and S100β further verified the role of increased astrocyte activity in BMAA-induced brain damage. This highlights the potential of imaging MS for probing chemical changes associated with neuropathological mechanisms in situ. This article is part of a Special Issue entitled: MALDI Imaging, edited by Dr. Corinna Henkel and Prof. Peter Hoffmann.

  16. Study of the tunable structure and two-dimension correlation infrared spectroscopy of Gd/3-methylbenzoic acid with o-phenanthroline, 2,2‧-and 4,4‧-bipyridines

    NASA Astrophysics Data System (ADS)

    Zhao, Lingyan; Chen, Yiping; Chai, Xiaochuan; Cui, Guanghua; Ren, Li; Yang, Yingxin; Zhang, Hao; Deng, Xiao chen

    2013-01-01

    Three rare earth compounds with 3-methylbenzoic acid (HMeBA) have been hydrothermally synthesized directly: Gd2(MeBA)6(o-Phen)21 (o-Phen = o-phenanthroline), [Gd2(MeBA)6(2,2'-bpy)]n2 (2,2'-bpy = 2,2'-bipyridine) and Gd (MeBA)3·(4,4'-bpy)0.53 (4,4'-bpy = 4,4'-bipyridine). These crystal structures were determined by single-crystal X-ray diffraction with the following data: 1: monoclinic, Cc; 2: monoclinic, P21/n; 3: Triclinic, P - 1. The compound 1 is a zero-dimensional Bi-nuclear oligomer and ligand -o- phenanthroline participates in the coordination; the compound 2 is a one-dimensional chain and the second ligand -2,2'-bpy participates in coordinating with the Gd ion; in particular, due to the existence of the second ligand -4,4'-bpy which acts as the bridge, the compound 3 is the two-dimensional layer. Additionally, in order to explore the structural characteristic, photo-luminescent and the 2D-IR correlation spectroscopy containing the temperature-induced structural variations and magnetism-induced structural variations are used.

  17. Nd0.5Bi2.5Fe5- y Ga y O12 thin films on Gd3Ga5O12 substrates prepared by metal-organic decomposition

    NASA Astrophysics Data System (ADS)

    Sasaki, Michimasa; Lou, Gengjian; Liu, Qi; Ninomiya, Minami; Kato, Takeshi; Iwata, Satoshi; Ishibashi, Takayuki

    2016-05-01

    Highly Bi-substituted neodymium iron gallium garnet thin films with a Bi content of 2.5, Nd0.5Bi2.5Fe5- y Ga y O12 (NBIGG) with y = 0-1, on gadolinium gallium garnet (111) and (100) substrates have been prepared by metal-organic decomposition. Magnetic properties and magnetic anisotropy energies were measured using an alternating field gradient magnetometer and by magnetic torque measurement, respectively. Faraday rotation spectra and hysteresis loops were measured using a Faraday rotation spectrometer. The magnetization of NBIGG thin films exhibiting a large Faraday rotation of 10-15°/µm decreased with increasing Ga content, resulting in increased effective magnetic anisotropy energy K eff. The dependence of the magnetic anisotropies on the Ga content is discussed in terms of the reverse magnetostrictive effect caused by thermal stress as well as the magnetocrystalline and shape anisotropies.

  18. Neurotropin promotes NGF signaling through interaction of GM1 ganglioside with Trk neurotrophin receptor in PC12 cells.

    PubMed

    Fukuda, Yu; Fukui, Takao; Hikichi, Chika; Ishikawa, Tomomasa; Murate, Kenichiro; Adachi, Takeshi; Imai, Hideki; Fukuhara, Koki; Ueda, Akihiro; Kaplan, Allen P; Mutoh, Tatsuro

    2015-01-30

    Activation of the high-affinity nerve growth factor (NGF) receptor Trk occurs through multiple processes consisted of translocation and clustering within the plasma membrane lipid rafts, dimerization and autophosphorylation. Here we found that a nonprotein extract of inflamed rabbit skin inoculated with vaccinia virus (Neurotropin(®)) enhanced efficiency of NGF signaling. In rat pheochromocytoma PC12 cells overexpressing Trk (PCtrk cells), Neurotropin augmented insufficient neurite outgrowth observed at suboptimal concentration of NGF (2ng/mL) in a manner depending on Trk kinase activity. Cellular exposure to Neurotropin resulted in an accumulation of Trk-GM1 complexes without affecting dimerization or phosphorylation states of Trk. Following NGF stimulation, Neurotropin significantly facilitated the time course of NGF-induced Trk autophosphorylation. These observations provide a unique mechanism controlling efficiency of NGF signaling, and raise the therapeutic potential of Neurotropin for various neurological conditions associated with neurotrophin dysfunction.

  19. Single chain FV constructs of anti-ganglioside GD2 antibodies for radioimaging and radioimmumotheraphy. Progress report

    SciTech Connect

    Cheung, N.K.V.; Larson, S.M.

    1993-11-01

    For the past several years, we have studied the anti-G{sub D2} murine monoclonal antibody, 3F8, in radiolabeled form, for diagnosis and therapy of neuroblastoma. The targeting properties of this antibody/antigen system are exceptional, with uptakes consistently in the highest range of reported results for in vivo human studies. The radioiodinated antibody 3F8 is now used by us as our criteria for diagnosis and staging of advanced neuroblastoma. This antibody is showing considerable promise also in our Phase I trials in Stage 4 neuroblastoma, and major responses are being seen at current dose level, with manageable marrow toxicity, but no limiting organ toxicity.

  20. Functional role of glycosphingolipids and gangliosides in control of cell adhesion, motility, and growth, through glycosynaptic microdomains.

    PubMed

    Regina Todeschini, Adriane; Hakomori, Sen-itiroh

    2008-03-01

    At cell surface microdomains, glycosyl epitopes, carried either by glycosphingolipids, N- or O-linked oligosaccharides, are recognized by carbohydrate-binding proteins or complementary carbohydrates. In both cases, the carbohydrate epitopes may be clustered with specific signal transducers, tetraspanins, adhesion receptors or growth factor receptors. Through this framework, carbohydrates can mediate cell signaling leading to changes in cellular phenotype. Microdomains involved in carbohydrate-dependent cell adhesion inducing cell activation, motility, and growth are termed "glycosynapse". In this review a historical synopsis of glycosphingolipids-enriched microdomains study leading to the concept of glycosynapse is presented. Examples of glycosynapse as signaling unit controlling the tumor cell phenotype are discussed in three contexts: (i) Cell-to-cell adhesion mediated by glycosphingolipids-to-glycosphingolipids interaction between interfacing glycosynaptic domains, through head-to-head (trans) carbohydrate-to-carbohydrate interaction. (ii) Functional role of GM3 complexed with tetraspanin CD9, and interaction of such complex with integrins, or with fibroblast growth factor receptor, to control tumor cell phenotype and its reversion to normal cell phenotype. (iii) Inhibition of integrin-dependent Met kinase activity by GM2/tetraspanin CD82 complex in glycosynaptic microdomain. Data present here suggest that the organizational status of glycosynapse strongly affects cellular phenotype influencing tumor cell malignancy.

  1. Diagnostic Utility of Auto Antibodies in Inflammatory Nerve Disorders.

    PubMed

    Emilien, Delmont; Hugh, Willison

    2015-06-04

    A wide range of autoantibodies have been described in immune-mediated nerve disorders that target glycans borne by glycolipids and glycoproteins enriched in the peripheral nerves. Their use as diagnostic biomarkers is very widespread, despite some limitations on sensitivity and specificity, and the lack of standardized assays and access to quality assurance schemes. Although many methods have been applied to measurement, ELISA, in the form of commercial kits or in-house assays, still remains the most widely available and convenient assay methodology.Some antibodies have a particularly robust and widely appreciated clinical significance. Thus, the anti-MAG IgM antibodies that are found in IgM paraprotein related neuropathies define a relatively uniform clinical and prognostic phenotype. IgG antibodies against gangliosides GM1 and GD1a are strongly associated with motor axonal variants of Guillain-Barré syndrome, and anti-GQ1b with Miller Fisher syndrome. In other chronic neuropathies, antibodies against disialylated gangliosides including GD1b and GD3 are detected in ataxic neuropathies, usually associated with an IgM paraprotein, and antibodies against GM1 and the complex GM1:GalC are frequently found in multifocal motor neuropathy. Unfortunately, autoantibodies strongly associated with the diagnosis of chronic inflammatory demyelinating polyneuropathies and with demyelinating forms of GBS are still lacking.Identification of autoantibodies that map onto a specific clinical phenotype not only allows for improved classification, but also provides better understanding of the pathophysiology of inflammatory neuropathies and the potential for therapeutic interventions.

  2. A somatically mutated human antiganglioside IgM antibody that induces experimental neuropathy in mice is encoded by the variable region heavy chain gene, V1-18.

    PubMed Central

    Willison, H J; O'Hanlon, G M; Paterson, G; Veitch, J; Wilson, G; Roberts, M; Tang, T; Vincent, A

    1996-01-01

    IgM paraproteins associated with autoimmune peripheral neuropathy and anti-Pr cold agglutinins react with sialic acid epitopes present on disialylated gangliosides including GD1b, GT1b, GQ1b, and GD3. A causal relationship between the paraprotein and the neuropathy has never been proven experimentally. From peripheral blood B cells of an affected patient, we have cloned a human hybridoma secreting an antidisialosyl IgM mAb, termed Ha1, that shows identical structural and functional characteristics to its serum counterpart. Variable region analysis shows Ha1 is encoded by the same VH1 family heavy chain gene, V1-18, as the only other known anti-Pr antibody sequence and is somatically mutated, suggesting that it [correction of is] arose in vivo in response to antigenic stimulation. In the rodent peripheral nervous system, Ha1 immunolocalizes to dorsal root ganglia, motor nerve terminals, muscle spindles, myelinated axons, and nodes of Ranvier. After intraperitoneal injection of affinity-purified antibody into mice for 10 d, electrophysiological recordings from the phrenic nerve-hemidiaphragm preparation demonstrated impairment of nerve excitability and a reduction in quantal release of neurotransmitter. These data unequivocally establish that an antidisialosyl antibody can exert pathophysiological effects on the peripheral nervous system and strongly support the view that the antibody contributes to the associated human disease. PMID:8636426

  3. Cancer Vaccines and Carbohydrate Epitopes

    PubMed Central

    Heimburg-Molinaro, Jamie; Lum, Michelle; Vijay, Geraldine; Jain, Miten; Almogren, Adel; Rittenhouse-Olson, Kate

    2011-01-01

    Tumor-associated carbohydrate antigens (TACA) result from the aberrant glycosylation that is seen with transformation to a tumor cell. The carbohydrate antigens that have been found to be tumor-associated include the mucin related Tn, Sialyl Tn, and Thomsen-Friedenreich antigens, the blood group Lewis related LewisY, Sialyl LewisX and Sialyl LewisA, and LewisX, (also known as stage-specific embryonic antigen-1, SSEA-1), the glycosphingolipids Globo H and stage-specific embryonic antigen-3 (SSEA-3), the sialic acid containing glycosphingolipids, the gangliosides GD2, GD3, GM2, fucosyl GM1, and Neu5GcGM3, and polysialic acid. Recent developments have furthered our understanding of the T-independent type II response that is seen in response to carbohydrate antigens. The selection of a vaccine target antigen is based on not only the presence of the antigen in a variety of tumor tissues but also on the role this antigen plays in tumor growth and metastasis. These roles for TACAs are being elucidated. Newly acquired knowledge in understanding the T-independent immune response and in understanding the key roles that carbohydrates play in metastasis are being applied in attempts to develop an effective vaccine response to TACAs. The role of each of the above mentioned carbohydrate antigens in cancer growth and metastasis and vaccine attempts using these antigens will be described. PMID:21964054

  4. Identification of Small Molecules against Botulinum Neurotoxin B Binding to Neuronal Cells at Ganglioside GT1b Binding Site with Low to Moderate Affinity

    DTIC Science & Technology

    2014-10-01

    recorded using a SpectraMax Plus plate reader with SoftMax ProVer 5.4 software (Molecular Devices, CA). Cell line: Human neuroblastoma cell line SH... neuroblastoma cell line SH-SY5Y (Table 2). Although most of the compounds were found to show some toxicity, three compounds were found to be relatively...50% are shown in red bold. Table 2 Compound toxicity for human neuroblastoma SH-SY5Y cell line. Sigmoidal Dose Response analysis except for

  5. Novel GM1 ganglioside-like peptide mimics prevent the association of cholera toxin to human intestinal epithelial cells in vitro.

    PubMed

    Yu, Robert K; Usuki, Seigo; Itokazu, Yutaka; Wu, Han-Chung

    2016-01-01

    Cholera is an acute diarrheal disease caused by infection in the gastrointestinal tract by the gram-negative bacterium, Vibrio cholerae, and is a serious public health threat worldwide. There has not been any effective treatment for this infectious disease. Cholera toxin (CT), which is secreted by V. cholerae, can enter host cells by binding to GM1, a monosialoganglioside widely distributed on the plasma membrane surface of various animal epithelial cells. The present study was undertaken to generate peptides that are conformationally similar to the carbohydrate epitope of GM1 for use in the treatment of cholera and related bacterial infection. For this purpose, we used cholera toxin B (CTB) subunit to select CTB-binding peptides that structurally mimic GM1 from a dodecamer phage-display library. Six GM1-replica peptides were selected by biopanning based on CTB recognition. Five of the six peptides showed inhibitory activity for GM1 binding to CTB. To test the potential of employing the peptide mimics for intervening with the bacterial infection, those peptides were examined for their binding capacity, functional inhibitory activity and in vitro effects using a human intestinal epithelial cell line, Caco-2 cells. One of the peptides, P3 (IPQVWRDWFKLP), was most effective in inhibiting cellular uptake of CTB and suppressing CT-stimulated cyclic adenosine monophosphate production in the cells. Our results thus provide convincing evidence that GM1-replica peptides could serve as novel agents to block CTB binding on epithelial cells and prevent the ensuing physiological effects of CT.

  6. Involvement of Ganglioside GM3 in G2/M Cell Cycle Arrest of Human Monocytic Cells Induced by Actinobacillus actinomycetemcomitans Cytolethal Distending Toxin

    PubMed Central

    Mise, Koji; Akifusa, Sumio; Watarai, Shinobu; Ansai, Toshihiro; Nishihara, Tatsuji; Takehara, Tadamichi

    2005-01-01

    Actinobacillus actinomycetemcomitans produces a toxin called cytolethal distending toxin (CDT), which causes host cell DNA damage leading to the induction of DNA damage checkpoint pathways. CDT consists of three subunits, CdtA, CdtB, and CdtC. CdtB is the active subunit of CDT and exerts its effect as a nuclease that damages nuclear DNA, triggering cell cycle arrest. In the present study, we confirmed that the only combination of toxin proteins causing cell cycle arrest was that of all three recombinant CDT (rCDT) protein subunits. Furthermore, in order for rCDT to demonstrate toxicity, it was necessary for CdtA and CdtC to access the cell before CdtB. The coexistence of CdtA and CdtC was necessary for these subunits to bind to the cell. Cells treated with the glucosylceramide synthesis inhibitor 1-phenyl-2-palmitoylamino-3-morpholino-1-propanol showed resistance to the cytotoxicity induced by rCDT. Furthermore, LY-B cells, which are deficient in the biosynthesis of sphingolipid, also showed resistance to the cytotoxicity induced by rCDT. To evaluate the binding of each subunit for glucosylceramides, we performed thin-layer chromatography immunostaining. The results indicated that each subunit reacted with the glycosphingolipids GM1, GM2, GM3, Gb3, and Gb4. The rCDT mixture incubated with liposomes containing GM3 displayed partially reduced toxicity. These results indicate that GM3 can act as a CDT receptor. PMID:16040998

  7. Effects of gangliosides from deer bone extract on the gene expressions of matrix metalloproteinases and collagen type II in interleukin-1β-induced osteoarthritic chondrocytes

    PubMed Central

    Suh, Hyung Joo; Lee, Hyunji; Min, Byung Jung; Jung, Sung Ug

    2016-01-01

    BACKGROUND/OBJECTIVES We investigated the anti-osteoarthritic effects of deer bone extract on the gene expressions of matrix metalloproteinases (MMPs) and collagen type II (COL2) in interleukin-1β-induced osteoarthritis (OA) chondrocytes. MATERIALS/METHODS Primary rabbit chondrocytes were treated as follows: CON (PBS treatment), NC (IL-1β treatment), PC (IL-1β + 100 µg/mL glucosamine sulphate/chondroitin sulphate mixture), and DB (IL-1β + 100 µg/mL deer bone extract). RESULTS The results of the cell viability assay indicated that deer bone extract at doses ranging from 100 to 500 µg/mL inhibits cell death in chondrocytes induced by IL-1β. Deer bone extract was able to significantly recover the mRNA expression of COL2 that was down-regulated by IL-1β (NC: 0.79 vs. DB: 0.87, P < 0.05) and significantly decrease the mRNA expression of MMP-3 (NC: 2.24 vs. DB: 1.75) and -13 (NC: 1.28 vs. DB: 0.89) in OA chondrocytes (P < 0.05). CONCLUSIONS We concluded that deer bone extract induces accumulation of COL2 through the down-regulation of MMPs in IL-1β-induced OA chondrocytes. Our results suggest that deer bone extract, which contains various components related to OA, including chondroitin sulphate, may possess anti-osteoarthritic properties and be of value in inhibiting the pathogenesis of OA. PMID:27909553

  8. Measurement of the binding of cholera toxin to GM1 gangliosides on solid supported lipid bilayer vesicles and inhibition by europium (III) chloride.

    PubMed

    Williams, Thomas L; Jenkins, A Toby A

    2008-05-21

    In this paper the immobilization of small unilamellar DMPC/GM1 lipid vesicles containing a water-soluble bodipy dye is described. The binding of the complete alphabeta toxin expressed by Vibrio cholerae to the attached vesicles was measured using Surface Plasmon Resonance (SPR) and a value of the dissociation constant K d obtained. Further measurements showed that the interaction of both the alphabeta-toxin and the beta-subunit alone resulted in the permeation of the lipid membrane, with release of a fluorophore contained within the vesicle being measured by combined SPR and Surface Plasmon enhanced Fluorescence Spectroscopy (SPFS). The leakage of dye through the membrane, measured by following the change in fluorescence, was fitted to a simple diffusion model. Finally, SPFS measurements of the effect of europium(III) chloride (EuCl 3) showed that cholera toxin binding and subsequent membrane permeation could be blocked by 1 micromol dm (-3) europium chloride. In view of the low oral toxicity of europium chloride, we speculate on the potential pharmaceutical applications of this molecule in the treatment of cholera infection.

  9. Immunoreactivity of the 14F7 Mab (Raised against N-Glycolyl GM3 Ganglioside) as a Positive Prognostic Factor in Non-Small-Cell Lung Cancer

    PubMed Central

    Blanco, Rancés; Rengifo, Charles E.; Cedeño, Mercedes; Frómeta, Milagros; Rengifo, Enrique; Carr, Adriana

    2012-01-01

    Lung carcinoma is the leading cause of cancer-related mortality worldwide. Therefore, numerous studies are focusing on the assessment of other biological and molecular prognostic factors in these tumors. We evaluated the relationship between 14F7 Mab reactivity, pathological features, DNA-content and S-phase fraction (SPF), and their impact in the survival of NSCLC patients. Hematoxylin and eosin staining and immunohistochemistry optical microscopy assays as well as DNA content and SPF measuring using flow cytometry were performed. The 14F7 reactivity was widely observed in NSCLC sections, no depending of the clinicopathological characteristics. We also obtained differences in the intensity of reaction with 14F7 as well as in the SPF between diploid and aneuploid carcinomas. Patients with diploid tumors showing higher SPF and 14F7 reaction joint to a low mitotic index displayed higher survival rates. Our results are in agreement with the assumption of the possible positive prognostic value of 14F7 staining in NSCLC. PMID:22482082

  10. Novel GM1 ganglioside-like peptide mimics prevent the association of cholera toxin to human intestinal epithelial cells in vitro

    PubMed Central

    Yu, Robert K; Usuki, Seigo; Itokazu, Yutaka; Wu, Han-Chung

    2016-01-01

    Cholera is an acute diarrheal disease caused by infection in the gastrointestinal tract by the gram-negative bacterium, Vibrio cholerae, and is a serious public health threat worldwide. There has not been any effective treatment for this infectious disease. Cholera toxin (CT), which is secreted by V. cholerae, can enter host cells by binding to GM1, a monosialoganglioside widely distributed on the plasma membrane surface of various animal epithelial cells. The present study was undertaken to generate peptides that are conformationally similar to the carbohydrate epitope of GM1 for use in the treatment of cholera and related bacterial infection. For this purpose, we used cholera toxin B (CTB) subunit to select CTB-binding peptides that structurally mimic GM1 from a dodecamer phage-display library. Six GM1-replica peptides were selected by biopanning based on CTB recognition. Five of the six peptides showed inhibitory activity for GM1 binding to CTB. To test the potential of employing the peptide mimics for intervening with the bacterial infection, those peptides were examined for their binding capacity, functional inhibitory activity and in vitro effects using a human intestinal epithelial cell line, Caco-2 cells. One of the peptides, P3 (IPQVWRDWFKLP), was most effective in inhibiting cellular uptake of CTB and suppressing CT-stimulated cyclic adenosine monophosphate production in the cells. Our results thus provide convincing evidence that GM1-replica peptides could serve as novel agents to block CTB binding on epithelial cells and prevent the ensuing physiological effects of CT. PMID:26405107

  11. Defective macroautophagic turnover of brain lipids in the TgCRND8 Alzheimer mouse model: prevention by correcting lysosomal proteolytic deficits.

    PubMed

    Yang, Dun-Sheng; Stavrides, Philip; Saito, Mitsuo; Kumar, Asok; Rodriguez-Navarro, Jose A; Pawlik, Monika; Huo, Chunfeng; Walkley, Steven U; Saito, Mariko; Cuervo, Ana M; Nixon, Ralph A

    2014-12-01

    Autophagy, the major lysosomal pathway for the turnover of intracellular organelles is markedly impaired in neurons in Alzheimer's disease and Alzheimer mouse models. We have previously reported that severe lysosomal and amyloid neuropathology and associated cognitive deficits in the TgCRND8 Alzheimer mouse model can be ameliorated by restoring lysosomal proteolytic capacity and autophagy flux via genetic deletion of the lysosomal protease inhibitor, cystatin B. Here we present evidence that macroautophagy is a significant pathway for lipid turnover, which is defective in TgCRND8 brain where lipids accumulate as membranous structures and lipid droplets within giant neuronal autolysosomes. Levels of multiple lipid species including several sphingolipids (ceramide, ganglioside GM3, GM2, GM1, GD3 and GD1a), cardiolipin, cholesterol and cholesteryl esters are elevated in autophagic vacuole fractions and lysosomes isolated from TgCRND8 brain. Lipids are localized in autophagosomes and autolysosomes by double immunofluorescence analyses in wild-type mice and colocalization is increased in TgCRND8 mice where abnormally abundant GM2 ganglioside-positive granules are detected in neuronal lysosomes. Cystatin B deletion in TgCRND8 significantly reduces the number of GM2-positive granules and lowers the levels of GM2 and GM3 in lysosomes, decreases lipofuscin-related autofluorescence, and eliminates giant lipid-containing autolysosomes while increasing numbers of normal-sized autolysosomes/lysosomes with reduced content of undigested components. These findings have identified macroautophagy as a previously unappreciated route for delivering membrane lipids to lysosomes for turnover, a function that has so far been considered to be mediated exclusively through the endocytic pathway, and revealed that autophagic-lysosomal dysfunction in TgCRND8 brain impedes lysosomal turnover of lipids as well as proteins. The amelioration of lipid accumulation in TgCRND8 by removing cystatin B

  12. Energy migration in the Ce 3+-doped Na-Gd phosphate glasses

    NASA Astrophysics Data System (ADS)

    Solovieva, Natalia; Nikl, Martin; Nitsch, Karel

    2007-09-01

    Luminescence decay kinetics of Ce3+-doped Gd3+-sensitized Na-phosphate glasses was measured within 4-300 K and analyzed to reveal the mechanism of energy migration through the Gd3+ subsystem to the Ce3+ emission centers. Dependencies of the asymptotic decay rates on the temperature are used to identify the type of phonon assistance in the Gd3+-Gd3+ energy transfer.

  13. Sialidase NEU4 is involved in glioblastoma stem cell survival

    PubMed Central

    Silvestri, I; Testa, F; Zappasodi, R; Cairo, C W; Zhang, Y; Lupo, B; Galli, R; Di Nicola, M; Venerando, B; Tringali, C

    2014-01-01

    The human sialidase, NEU4, has emerged as a possible regulator of neuronal differentiation and its overexpression has been demonstrated to promote the acquisition of a stem cell-like phenotype in neuroblastoma cells. In this paper, we demonstrated that glioblastoma stem cells (GSCs) isolated from glioblastoma multiforme (GBM) cell lines and patients' specimens as neurospheres are specifically marked by the upregulation of NEU4; in contrast, the expression of NEU4 is very low in non-neurosphere-differentiated GBM cells. We showed that NEU4 silencing by miRNA or a chemical inhibitor of its catalytic activity triggered key events in GSCs, including (a) the activation of the glycogen synthase kinase 3β, with the consequent inhibition of Sonic Hedgehog and Wnt/β-catenin signalling pathways; (b) the decrease of the stem cell-like gene expression and marker signatures, evidenced by the reduction of NANOG, OCT-4, SOX-2, CD133 expression, ganglioside GD3 synthesis, and an altered protein glycosylation profile; and (c) a significant decrease in GSCs survival. Consistent with this finding, increased NEU4 activity and expression induced in the more differentiated GBM cells by the NEU4 agonist thymoquinone increased the expression of OCT-4 and GLI-1. Thus, NEU4 expression and activity appeared to help to determine the molecular signature of GSCs and to be closely connected with their survival properties. Given the pivotal role played by GSCs in GBM lethality, our results strongly suggest that NEU4 inhibition could significantly improve current therapies against this tumour. PMID:25144716

  14. A single point mutation of the influenza C virus glycoprotein (HEF) changes the viral receptor-binding activity.

    PubMed

    Szepanski, S; Gross, H J; Brossmer, R; Klenk, H D; Herrler, G

    1992-05-01

    From strain JHB/1/66 of influenza C virus a mutant was derived with a change in the cell tropism. The mutant was able to grow in a subline of Madin-Darby canine kidney cells (MDCK II) which is resistant to infection by the parent virus due to a lack of receptors. Inactivation of cellular receptors by either neuraminidase or acetylesterase and generation of receptors by resialylation of cells with N-acetyl-9-O-acetylneuraminic acid (Neu5,9Ac2) indicated that 9-O-acetylated sialic acid is a receptor determinant for both parent and mutant virus. However, the mutant required less Neu5,9Ac2 on the cell surface for virus attachment than the parent virus. The increased binding efficiency enabled the mutant to infect cells with a low content of 9-O-acetylated sialic acid which were resistant to the parent virus. By comparing the nucleotide sequences of the glycoprotein (HEF) genes of the parent and the mutant virus only a single point mutation could be identified on the mutant gene. This mutation at nucleotide position 872 causes an amino acid exchange from threonine to isoleucine at position 284 on the amino acid sequence. Sequence similarity with a stretch of amino acids involved in the receptor-binding pocket of the influenza A hemagglutinin suggests that the mutation site on the influenza C glycoprotein (HEF) is part of the receptor-binding site.

  15. A case of severe chronic inflammatory demyelinating polyradiculoneuropathy with monoclonal gammopathy of undetermined significance with alternating immunoglobulin class to IgM from IgA.

    PubMed

    Hayashi, Shintaro; Nagamine, Shun; Makioka, Kouki; Kusunoki, Susumu; Okamoto, Koichi

    2016-09-29

    A 71-year-old woman with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) with IgA-λ monoclonal gammopathy of undetermined significance (MGUS) showed the acute development of tetraplegia, respiratory failure, and a marked fluctuation of the blood pressure. Intravenous (IV) high-dose steroid therapy (methylprednisolone: 1 g/day × 3 days), followed by oral prednisolone (PSL) (40 mg/day), and IV immunoglobulin (IVIg, 0.4 g/kg/day × 5 days) administrations resulted in the amelioration of these symptoms. However, they soon relapsed, which eventually led to complete tetraplegia and the need for mechanical ventilation. At this time, serum components of IgA-λ and IgM-λ were biclonally positive. Seven courses of plasma exchange and the alternative administration of dexamethasone (12 mg/day) and methtorexate (15 mg/week) were conducted, but with no significant improvement. Nine months after admission, she showed totally-locked in syndrome. Cryo-preserved serum obtained at this time showed high titers of IgM class antibodies against ganglioside (GD3 +++, GT1a ++++, GT1b ++, GQ1b +++, and GD1b +++), which had been negative on admission. Biopsy of the left sural nerve showed moderate reductions of large and small myelinated fibers with no inflammation, no depositions of amyloid, IgG, IgA, or IgM, and teased fiber findings revealed neither myelin ovoids nor segmental demyelination. Alternatively, melphalan at 5 mg and PSL at 32 mg were administered, with no amelioration, while serum IgA-λ monoclonal protein diminished, and IgM-λ M protein positivity was continuously observed. She frequently developed sepsis; therefore, we could no longer continue any immunosupressive therapies, but monthly IVIg administrations were given. Twelve months after admission, her neurological symptoms gradually improved and she was weaned off of mechanical ventilation. Eighteen months after admission, her muscle strength corresponded to 2 on manual muscle testing

  16. Neurobiology and cellular pathogenesis of glycolipid storage diseases.

    PubMed Central

    Walkley, Steven U

    2003-01-01

    Disorders of lysosomal metabolism often involve the accumulation of specific types of glycolipid, particularly gangliosides, because of either degradative failure or other currently unknown mechanisms. Although the precise role of gangliosides in cells remains enigmatic, the presence of specific abnormalities secondary to ganglioside accumulation in lysosomal diseases has suggested important biological functions. Chief among these is the growth of new dendrites on particular classes of mature neurons secondary to an increase in GM2 ganglioside. That GM2 has also been shown to be elevated in normal immature neurons coincident with dendritic sprouting provides a compelling argument that this ganglioside plays a role in dendritic initiation. This discovery has led to the search for other regulators of dendritic differentiation that may in some way be linked to the expression and/or function of GM2 ganglioside. Principal candidates that have emerged include tyrosine kinase receptors, small GTPases and calcium/calmodulin-dependent protein kinase II. Understanding the mechanism underlying ectopic dendritogenesis in lysosomal diseases can be expected to generate significant insight into the control of dendritic plasticity in normal brain. The detrimental aspects of ganglioside accumulation in storage diseases as well as the potential link between gangliosides and dendritogenesis also provide a strong rationale for developing pharmacological means to manipulate ganglioside expression in neurons. PMID:12803923

  17. Research and Development on Laser, Semiconducting and Magnetic Materials

    DTIC Science & Technology

    studied included YAl 03:Er(3+), SrF2 :(Gd(3+), and Ce(3+), CdF2: (Gd(3+), Ce(3+)) . High-resolution optical spectroscopy and EPR studies were carried...system. Extensive theoretical and computational studies were carried out on the YAl03 and SrF2 doped materials. An experimental facility for the

  18. Construction of Synthetic Immunogens in View of Developing Orally-Active Anti-Enterotoxigenic E. coli Vaccines

    DTIC Science & Technology

    1989-05-31

    The aim of this research was to build immunogens susceptible of inducing a response against enterotoxigenic E . coli (Escherichia coli) (ETEC...ganglioside which represents the toxin receptor. Two different E . coli peptides have been analyzed by HPLC (high performance liquid chromatography). Eight...enterotoxigenic E . coli immunogens, 3-Muramyl dipeptides, 4-Synthetic cholera toxin receptor, 5-GM1 ganglioside, RA 1.

  19. An Open Receptor-Binding Cavity of Hemagglutinin-Esterase-Fusion Glycoprotein from Newly-Identified Influenza D Virus: Basis for Its Broad Cell Tropism.

    PubMed

    Song, Hao; Qi, Jianxun; Khedri, Zahra; Diaz, Sandra; Yu, Hai; Chen, Xi; Varki, Ajit; Shi, Yi; Gao, George F

    2016-01-01

    Influenza viruses cause seasonal flu each year and pandemics or epidemic sporadically, posing a major threat to public health. Recently, a new influenza D virus (IDV) was isolated from pigs and cattle. Here, we reveal that the IDV utilizes 9-O-acetylated sialic acids as its receptor for virus entry. Then, we determined the crystal structures of hemagglutinin-esterase-fusion glycoprotein (HEF) of IDV both in its free form and in complex with the receptor and enzymatic substrate analogs. The IDV HEF shows an extremely similar structural fold as the human-infecting influenza C virus (ICV) HEF. However, IDV HEF has an open receptor-binding cavity to accommodate diverse extended glycan moieties. This structural difference provides an explanation for the phenomenon that the IDV has a broad cell tropism. As IDV HEF is structurally and functionally similar to ICV HEF, our findings highlight the potential threat of the virus to public health.

  20. An Open Receptor-Binding Cavity of Hemagglutinin-Esterase-Fusion Glycoprotein from Newly-Identified Influenza D Virus: Basis for Its Broad Cell Tropism

    PubMed Central

    Song, Hao; Qi, Jianxun; Khedri, Zahra; Diaz, Sandra; Yu, Hai; Chen, Xi; Varki, Ajit; Shi, Yi; Gao, George F.

    2016-01-01

    Influenza viruses cause seasonal flu each year and pandemics or epidemic sporadically, posing a major threat to public health. Recently, a new influenza D virus (IDV) was isolated from pigs and cattle. Here, we reveal that the IDV utilizes 9-O-acetylated sialic acids as its receptor for virus entry. Then, we determined the crystal structures of hemagglutinin-esterase-fusion glycoprotein (HEF) of IDV both in its free form and in complex with the receptor and enzymatic substrate analogs. The IDV HEF shows an extremely similar structural fold as the human-infecting influenza C virus (ICV) HEF. However, IDV HEF has an open receptor-binding cavity to accommodate diverse extended glycan moieties. This structural difference provides an explanation for the phenomenon that the IDV has a broad cell tropism. As IDV HEF is structurally and functionally similar to ICV HEF, our findings highlight the potential threat of the virus to public health. PMID:26816272

  1. Advanced Technologies in Sialic Acid and Sialoglycoconjugate Analysis.

    PubMed

    Kitajima, Ken; Varki, Nissi; Sato, Chihiro

    2015-01-01

    Although the structural diversity of sialic acid (Sia) is rapidly expanding, understanding of its biological significance has lagged behind. Advanced technologies to detect and probe diverse structures of Sia are absolutely necessary not only to understand further biological significance but also to pursue medicinal and industrial applications. Here we describe analytical methods for detection of Sia that have recently been developed or improved, with a special focus on 9-O-acetylated N-acetylneuraminic acid (Neu5,9Ac), N-glycolylneuraminic acid (Neu5Gc), deaminoneuraminic acid (Kdn), O-sulfated Sia (SiaS), and di-, oligo-, and polysialic acid (diSia/oligoSia/polySia) in glycoproteins and glycolipids. Much more attention has been paid to these Sia and sialoglycoconjugates during the last decade, in terms of regulation of the immune system, neural development and function, tumorigenesis, and aging.

  2. Upconverting rare-earth nanoparticles with a paramagnetic lanthanide complex shell for upconversion fluorescent and magnetic resonance dual-modality imaging

    NASA Astrophysics Data System (ADS)

    Wang, Yan; Ji, Lei; Zhang, Bingbo; Yin, Peihao; Qiu, Yanyan; Song, Daqian; Zhou, Juying; Li, Qi

    2013-05-01

    Multi-modal imaging based on multifunctional nanoparticles is a promising alternative approach to improve the sensitivity of early cancer diagnosis. In this study, highly upconverting fluorescence and strong relaxivity rare-earth nanoparticles coated with paramagnetic lanthanide complex shells and polyethylene glycol (PEGylated UCNPs@DTPA-Gd3+) are synthesized as dual-modality imaging contrast agents (CAs) for upconverting fluorescent and magnetic resonance dual-modality imaging. PEGylated UCNPs@DTPA-Gd3+ with sizes in the range of 32-86 nm are colloidally stable. They exhibit higher longitudinal relaxivity and transverse relaxivity in water (r1 and r2 values are 7.4 and 27.8 s-1 per mM Gd3+, respectively) than does commercial Gd-DTPA (r1 and r2 values of 3.7 and 4.6 s-1 per mM Gd3+, respectively). They are found to be biocompatible. In vitro cancer cell imaging shows good imaging contrast of PEGylated UCNPs@DTPA-Gd3+. In vivo upconversion fluorescent imaging and T1-weighted MRI show excellent enhancement of both fluorescent and MR signals in the livers of mice administered PEGylated UCNPs@DTPA-Gd3+. All the experimental results indicate that the synthesized PEGylated UCNPs@DTPA-Gd3+ present great potential for biomedical upconversion of fluorescent and magnetic resonance dual-modality imaging applications.

  3. Gadolinium-hydrogen ion exchange of zirconium phosphate

    NASA Technical Reports Server (NTRS)

    Liu, D. C.; Power, J. L.

    1972-01-01

    The Gd(+3)/H(+) ion exchange on a commercial zirconium phosphate ion exchanger was investigated in chloride, sulfate, and phosphate solutions of Gd(+3) at gadolinium concentrations of 0.001 to 1 millimole per cc and in the pH range of 0 to 3.5. Relatively low Gd(+3) capacities, in the range of 0.01 to 0.1 millimole per g of ion exchanger were found at room temperature. A significant difference in Gd(+3) sorption was observed, depending on whether the ion exchanger was converted from initial conditions of greater or lesser Gd(+3) sorption than the specific final conditions. Correlations were found between decrease in Gd(+3) capacity and loss of exchanger phosphate groups due to hydrolysis during washing and between increase in capacity and treatment with H3PO4. Fitting of the experimental data to ideal ion exchange equilibrium expressions indicated that each Gd(+3) ion is sorbed on only one site of the ion exchanger. The selectivity quotient was determined to be 2.5 + or - 0.4 at room temperature on gadolinium desorption in chloride solutions.

  4. Microcalorimetric studies on the energy release of isolated rat mitochondria under different concentrations of gadolinium (III).

    PubMed

    Zhao, Jie; Ma, Long; Xiang, Xun; Guo, Qing-Lian; Jiang, Feng-Lei; Liu, Yi

    2016-06-01

    Gadolinium-based compounds are most widely utilized for paramagnetic contrast agents, but, the toxicological mechanism of gadolinium (Gd) had not been fully elucidated since the first report about Gd anomaly. In this work, we analyzed the effect of Gd(3+) on mitochondria in vitro by microcalorimetry. Microcalorimetry can provide detailed kinetic and thermodynamic information from thermogenic curve. At the tested concentration, Gd(3+) induced the increase of growth rate constant (k1). At high concentration (100-500 μM), the maximum power output time (tm), the decline rate constant (-k2) and the time of activity recovery phase (tR) decreased with the addition of Gd(3+) and the maximum power output (Pm) increased. At low concentration (0-100 μM), the changes were different from high concentration. From the results we concluded that the effect of different concentrations of Gd(3+) had a relationship with time, high concentration of Gd(3+) induced mitochondrial energy metabolism disturb however low concentration may promote mitochondrial adaption to physiological stresses. The effect of low concentration of Gd(3+) need more work to elucidate the mechanism. The results of total heat output (Q) and mitochondrial respiratory activities suggested high concentrations of Gd(3+) could accelerate adenosine triphosphate (ATP) consumption under respiratory system damaged.

  5. Clinical phenotype of patients with neuropathy associated with monoclonal gammopathy: a comparative study and a review of the literature.

    PubMed

    Stork, Abraham C J; van der Pol, W-Ludo; Franssen, Hessel; Jacobs, Bart C; Notermans, Nicolette C

    2014-07-01

    The objective of this study was to investigate if the clinical and electrophysiological phenotype of patients with polyneuropathy associated with IgM monoclonal gammopathy (IgM-PNP) is related to the presence of antibodies against gangliosides or myelin-associated glycoprotein (MAG). We compared clinical and nerve conduction study (NCS) characteristics of 11 IgM-PNP patients with antibodies against asialo-GM1 or gangliosides (GM1, GD1a, GD1b, GM2 or GQ1b) to 11 consecutive IgM-PNP patients with anti-MAG neuropathy and to 9 IgM-PNP patients without antibodies against either MAG or gangliosides. Patients with anti-ganglioside antibodies could not be differentiated from those with anti-MAG antibodies based on clinical characteristics. However, within the group of anti-ganglioside antibody positive patients, antibodies against GD1b and GQ1b were associated with a purely sensory neuropathy (p = 0.002), while asymmetric weakness with symmetric sensory loss was associated with anti-asialo-GM1 antibodies. In conclusion, polyneuropathy associated with IgM monoclonal gammopathy and anti-ganglioside antibodies clinically resembles anti-MAG neuropathy. Pure sensory neuropathy and marked asymmetry may suggest the presence of anti-ganglioside rather than anti-MAG antibodies.

  6. Dysregulated Expression of Glycolipids in Tumor Cells: From Negative Modulator of Anti-tumor Immunity to Promising Targets for Developing Therapeutic Agents

    PubMed Central

    Daniotti, Jose Luis; Lardone, Ricardo D.; Vilcaes, Aldo A.

    2016-01-01

    Glycolipids are complex molecules consisting of a ceramide lipid moiety linked to a glycan chain of variable length and structure. Among these are found the gangliosides, which are sialylated glycolipids ubiquitously distributed on the outer layer of vertebrate plasma membranes. Changes in the expression of certain species of gangliosides have been described to occur during cell proliferation, differentiation, and ontogenesis. However, the aberrant and elevated expression of gangliosides has been also observed in different types of cancer cells, thereby promoting tumor survival. Moreover, gangliosides are actively released from the membrane of tumor cells, having a strong impact on impairing anti-tumor immunity. Beyond the undesirable effects of gangliosides in cancer cells, a substantial number of cancer immunotherapies have been developed in recent years that have used gangliosides as the main target. This has resulted in successful immune cell- or antibody-responses against glycolipids, with promising results having been obtained in clinical trials. In this review, we provide a general overview on the metabolism of glycolipids, both in normal and tumor cells, as well as examining glycolipid-mediated immune modulation and the main successes achieved in immunotherapies using gangliosides as molecular targets. PMID:26779443

  7. Novel insights into the lipidome of glioblastoma cells based on a combined PLSR and DD-HDS computational analysis

    NASA Astrophysics Data System (ADS)

    Lespinats, S.; Meyer-Bäse, Anke; He, Huan; Marshall, Alan G.; Conrad, Charles A.; Emmett, Mark R.

    2009-05-01

    Partial Least Square Regression (PLSR) and Data-Driven High Dimensional Scaling (DD-HDS) are employed for the prediction and the visualization of changes in polar lipid expression induced by different combinations of wild-type (wt) p53 gene therapy and SN38 chemotherapy of U87 MG glioblastoma cells. A very detailed analysis of the gangliosides reveals that certain gangliosides of GM3 or GD1-type have unique properties not shared by the others. In summary, this preliminary work shows that data mining techniques are able to determine the modulation of gangliosides by different treatment combinations.

  8. A novel cryogenic magnetic refrigerant metal-organic framework based on 1D gadolinium(III) chain

    NASA Astrophysics Data System (ADS)

    Tang, Qun; Li, Peng-Fei; Zou, Zhi-Ming; Liu, Zheng; Liu, Shu-Xia

    2017-02-01

    A metal-organic framework (MOF) based on gadolinium ion (Gd3+) and tricarboxylate ligand, [Gd(BTPCA)(H2O)]·2DMF·3H2O (Gd-BTPCA) (H3BTPCA =1,1‧,1‧-(benzene-1,3,5-triyl)tripiperidine-4-carboxylic acid; DMF=dimethylformamide), was synthesized and structurally characterized. The adjacent Gd3+ ions are intraconnected by the carboxylate groups of the BTPCA3- ligands to form a 1D Gd3+ ion chain. The 1D Gd3+ ion chains are interconnected by the BTPCA3- ligands, giving rise to a 3D framework with 1D open channel. The magnetic studies indicate that Gd-BTPCA exhibits weak ferromagnetic interactions, and acts as a cryogenic magnetic refrigerant having the magnetic entropy change (-ΔSm) of 20.40 J kg-1 K-1 for ΔH =7 T at 3 K.

  9. Optical and Mechanical Properties of Infrared Materials.

    DTIC Science & Technology

    1980-07-01

    Eagle- Picher Co. The crystals were grown under an inert gas pressure by using a modified Bridgeman technique. The ingots are polycrystalline with large...ZnSe:Al samples which were annealed under different Se pressures (see part III-A of this report) prior to Li diffusion showed bands after Li diffusion which...grains CaF2 + 0.1% Gd 3+Optovac Crystal CaF2 + 1.0% Gd 3 + ofofo CaF2 + 1.0% Ce3+iiso SrF2 + 1.0% Gd 3 ifofo BaF2 + 1.0% Gd 3+ ’ tII CaF2 + Th 3

  10. Magnetic and dielectric properties and Raman spectroscopy of GdCrO3 nanoparticles

    NASA Astrophysics Data System (ADS)

    Jaiswal, Adhish; Das, Raja; Vivekanand, K.; Maity, Tuhin; Abraham, Priya Mary; Adyanthaya, Suguna; Poddar, Pankaj

    2010-01-01

    The rare earth orthochromites are extremely interesting due to the richness of their optical, dielectric, and magnetic properties as well as due to their multiferroic properties which make them suitable materials to study in the nanoregime. However, the wet-chemical synthesis of these materials in nanosize is nontrivial. Here, we report for the first time, the detailed Raman spectra as well as magnetic and dielectric properties of chemically synthesized GdCrO3 nanoparticles of size ranging from 40 to 60 nm. The magnetic properties are dictated by competing Cr3+-Cr3+, Gd3+-Cr3+, and Gd3+-Gd3+ superexchange interactions in different temperature regions, resulting into an antiferromagnetic ordering at 167 K due to the Cr3+-Cr3+ followed by weak ferromagnetic ordering due to the onset of Cr3+-Gd3+ interactions. At lower temperature, it shows weak antiferromagnetic ordering due to Gd3+-Gd3+ interaction. Below 95 K, GdCrO3 nanoparticles showed the presence of negative magnetization due to Gd3+ and Cr3+ interactions resulting into weak ferromagnetic coupling. The Raman spectroscopy shows the characteristic Raman shifts indicating that below 450 cm-1, Gd3+ ions play a dominant role in determining the phonon frequencies of GdCrO3, and above 450 cm-1, the Cr+3 ions dominate. We also present for the first time the low temperature dielectric constant and loss tangent data for GdCrO3 in a broad temperature and frequency range. The dielectric constant shows a decrease in comparison to the bulk values due to the size dependent effects. It also shows a peak centered at around 320 K above which it shows a sharp decrease. The dielectric loss value in GdCrO3 nanoparticles is quite small and shows an interesting frequency dependent anomaly at lower temperature which might be due to the coupling between magnetic and dielectric order parameters.

  11. Neuronal expression of glucosylceramide synthase in central nervous system regulates body weight and energy homeostasis.

    PubMed

    Nordström, Viola; Willershäuser, Monja; Herzer, Silke; Rozman, Jan; von Bohlen Und Halbach, Oliver; Meldner, Sascha; Rothermel, Ulrike; Kaden, Sylvia; Roth, Fabian C; Waldeck, Clemens; Gretz, Norbert; de Angelis, Martin Hrabě; Draguhn, Andreas; Klingenspor, Martin; Gröne, Hermann-Josef; Jennemann, Richard

    2013-01-01

    Hypothalamic neurons are main regulators of energy homeostasis. Neuronal function essentially depends on plasma membrane-located gangliosides. The present work demonstrates that hypothalamic integration of metabolic signals requires neuronal expression of glucosylceramide synthase (GCS; UDP-glucose:ceramide glucosyltransferase). As a major mechanism of central nervous system (CNS) metabolic control, we demonstrate that GCS-derived gangliosides interacting with leptin receptors (ObR) in the neuronal membrane modulate leptin-stimulated formation of signaling metabolites in hypothalamic neurons. Furthermore, ganglioside-depleted hypothalamic neurons fail to adapt their activity (c-Fos) in response to alterations in peripheral energy signals. Consequently, mice with inducible forebrain neuron-specific deletion of the UDP-glucose:ceramide glucosyltransferase gene (Ugcg) display obesity, hypothermia, and lower sympathetic activity. Recombinant adeno-associated virus (rAAV)-mediated Ugcg delivery to the arcuate nucleus (Arc) significantly ameliorated obesity, specifying gangliosides as seminal components for hypothalamic regulation of body energy homeostasis.

  12. Neuronal Expression of Glucosylceramide Synthase in Central Nervous System Regulates Body Weight and Energy Homeostasis

    PubMed Central

    Nordström, Viola; Willershäuser, Monja; Herzer, Silke; Rozman, Jan; von Bohlen und Halbach, Oliver; Meldner, Sascha; Rothermel, Ulrike; Kaden, Sylvia; Roth, Fabian C.; Waldeck, Clemens; Gretz, Norbert; de Angelis, Martin Hrabě; Draguhn, Andreas; Klingenspor, Martin

    2013-01-01

    Hypothalamic neurons are main regulators of energy homeostasis. Neuronal function essentially depends on plasma membrane-located gangliosides. The present work demonstrates that hypothalamic integration of metabolic signals requires neuronal expression of glucosylceramide synthase (GCS; UDP-glucose:ceramide glucosyltransferase). As a major mechanism of central nervous system (CNS) metabolic control, we demonstrate that GCS-derived gangliosides interacting with leptin receptors (ObR) in the neuronal membrane modulate leptin-stimulated formation of signaling metabolites in hypothalamic neurons. Furthermore, ganglioside-depleted hypothalamic neurons fail to adapt their activity (c-Fos) in response to alterations in peripheral energy signals. Consequently, mice with inducible forebrain neuron-specific deletion of the UDP-glucose:ceramide glucosyltransferase gene (Ugcg) display obesity, hypothermia, and lower sympathetic activity. Recombinant adeno-associated virus (rAAV)-mediated Ugcg delivery to the arcuate nucleus (Arc) significantly ameliorated obesity, specifying gangliosides as seminal components for hypothalamic regulation of body energy homeostasis. PMID:23554574

  13. Bottom-Up Synthesis of Metal-Ion-Doped WS₂ Nanoflakes for Cancer Theranostics.

    PubMed

    Cheng, Liang; Yuan, Chao; Shen, Sida; Yi, Xuan; Gong, Hua; Yang, Kai; Liu, Zhuang

    2015-11-24

    Recently, two-dimensional transition metal dichalcogenides (TMDCs) have received tremendous attention in many fields including biomedicine. Herein, we develop a general method to dope different types of metal ions into WS2 nanoflakes, a typical class of TMDCs, and choose Gd(3+)-doped WS2 (WS2:Gd(3+)) with polyethylene glycol (PEG) modification as a multifunctional agent for imaging-guided combination cancer treatment. While WS2 with strong near-infrared (NIR) absorbance and X-ray attenuation ability enables contrasts in photoacoustic (PA) imaging and computed tomography (CT), Gd(3+) doping offers the nanostructure a paramagnetic property for magnetic resonance (MR) imaging. As revealed by trimodal PA/CT/MR imaging, WS2:Gd(3+)-PEG nanoflakes showed efficient tumor homing after intravenous injection. In vivo cancer treatment study further uncovered that WS2:Gd(3+)-PEG could not only convert NIR light into heat for photothermal therapy (PTT) but also enhance the ionizing irradiation-induced tumor damage to boost radiation therapy (RT). Owing to the improved tumor oxygenation after the mild PTT, the combination of PTT and RT induced by WS2:Gd(3+)-PEG resulted in a remarkable synergistic effect to destroy cancer. Our work highlights the promise of utilizing inherent physical properties of TMDC-based nanostructures, whose functions could be further enriched by elementary doping, for applications in multimodal bioimaging and synergistic cancer therapy.

  14. Geometrical confinement of gadolinium-based contrast agents in nanoporous particles enhances T1 contrast

    PubMed Central

    Ananta, Jeyarama S.; Godin, Biana; Sethi, Richa; Moriggi, Loick; Liu, Xuewu; Serda, Rita E.; Krishnamurthy, Ramkumar; Muthupillai, Raja; Bolskar, Robert D.; Helm, Lothar; Ferrari, Mauro; Wilson, Lon J.; Decuzzi, Paolo

    2010-01-01

    Magnetic resonance imaging contrast agents are currently designed by modifying their structural and physiochemical properties in order to improve relaxivity and to enhance image contrast. Here we show a general method for increasing relaxivity by confining contrast agents inside the nanoporous structure of silicon particles. Magnevist, gadofullerenes and gadonanotubes were loaded inside the pores of quasi-hemispherical and discoidal particles. For all combinations of nanoconstructs, a boost in longitudinal proton relaxivity r1 was observed: for Magnevist, r1~14 mM-1s-1/Gd3+ion (~8.15×10+7 mM-1s-1/construct); for gadofullerenes, r1~200 mM-1s-1/Gd3+ion (~7×10+9 mM-1s-1/construct); for gadonanotubes, r1~150 mM-1s-1/Gd3+ion (~2×10+9 mM-1s-1/construct). These relaxivity values are about 4 to 50 times larger than that of clinically-available gadolinium-based agents (~4 mM-1s-1 /Gd3+ion). The enhancement in contrast is attributed to the geometrical confinement of the agents, which influences the paramagnetic behavior of the Gd3+ions. Thus, nanoscale confinement offers a new and general strategy for enhancing the contrast of gadolinium-based contrast agents. PMID:20972435

  15. Evidence for Extracellular ATP as a Stress Signal in a Single-Celled Organism

    PubMed Central

    Sivaramakrishnan, Venketesh

    2015-01-01

    ATP is omnipresent in biology and acts as an extracellular signaling molecule in mammals. Information regarding the signaling function of extracellular ATP in single-celled eukaryotes is lacking. Here, we explore the role of extracellular ATP in cell volume recovery during osmotic swelling in the amoeba Dictyostelium. Release of micromolar ATP could be detected during cell swelling and regulatory cell volume decrease (RVD) phases during hypotonic challenge. Scavenging ATP with apyrase caused profound cell swelling and loss of RVD. Apyrase-induced swelling could be rescued by 100 μM βγ-imidoATP. N-Ethylmalemide (NEM), an inhibitor of vesicular exocytosis, caused heightened cell swelling, loss of RVD, and inhibition of ATP release. Amoebas with impaired contractile vacuole (CV) fusion (drainin knockout [KO] cells) displayed increased swelling but intact ATP release. One hundred micromolar Gd3+ caused cell swelling while blocking any recovery by βγ-imidoATP. ATP release was 4-fold higher in the presence of Gd3+. Cell swelling was associated with an increase in intracellular nitric oxide (NO), with NO-scavenging agents causing cell swelling. Swelling-induced NO production was inhibited by both apyrase and Gd3+, while NO donors rescued apyrase- and Gd3+-induced swelling. These data suggest extracellular ATP released during cell swelling is an important signal that elicits RVD. Though the cell surface receptor for ATP in Dictyostelium remains elusive, we suggest ATP operates through a Gd3+-sensitive receptor that is coupled with intracellular NO production. PMID:26048010

  16. Structures and dynamics of glycosphingolipid-containing lipid mixtures as raft models of plasma membrane

    NASA Astrophysics Data System (ADS)

    Hirai, M.; Koizumi, M.; Hirai, H.; Hayakawa, T.; Yuyama, K.; Suzuki, N.; Kasahara, K.

    2005-08-01

    The structure and function of mammalian plasma membrane microdomains, so-called rafts, are among the hot topics in cell biology, since it is suggested that these domains are involved in important membrane-associated events, especially ones such as signal transduction, which were frequently seen in physiological and immunological studies. In spite of the accumulation of large amounts of evidence, results on physical properties of the structure and dynamics of membranes such as those in intact cells are less abundant. In this report we treat the structure and dynamics of glycosphingolipid (ganglioside)-cholesterol and glycosphingolipid (ganglioside)-cholesterol-phospholipid mixtures used as models of rafts and plasma membranes. The present results clearly show that the incorporation of cholesterol with ganglioside aggregates is limited to a maximum miscibility of the molar ratio between the ganglioside and cholesterol ranging from ~1/1 to 1/3 and that small vesicles with diameters of about 250-300 Å form. These molar ratios and sizes agree well with the reported constituent ratio and minimum size for the rafts. In the vesicle systems containing ganglioside, cholesterol, and phospholipid (PC, DSPC, DOPC, POPC), the bending modulus tends to take the smallest value at the molar ratio of [gang]/[chol]/[phospholipid] = 0.1/0.1/1. The present results would strongly support a functional physical property of the raft model: sphingolipids and cholesterol clustering to form rafts that move within the fluid lipid bilayer.

  17. Brucella melitensis infection associated with Guillain-Barré syndrome through molecular mimicry of host structures.

    PubMed

    Watanabe, Kenta; Kim, Suk; Nishiguchi, Megumi; Suzuki, Hiroshi; Watarai, Masahisa

    2005-08-01

    Brucella melitensis is a facultative intracellular bacterium that can survive inside macrophages and the causative agent of brucellosis. In the present study, we found that a lipooligosaccharide of B. melitensis has a GM1 ganglioside-like structure and shows a strong antibody response in mice. The cholera toxin B subunit, which binds to GM1 ganglioside specifically, reacted with the surface of B. melitensis. Immunization with B. melitensis induced the production of anti-GM1 ganglioside antibodies in mice and serum from immunized mice showed a cross-reaction with Guillain-Barré syndrome (GBS)-associated Campylobacter jejuni, but not non-GBS-associated C. jejuni. When B. melitensis was treated with a neuraminidase, antibody responses disappeared. B. melitensis immunization induced the production of anti-GM1 ganglioside antibodies in BALB/c mice but not in C57BL/6 and ddY mice, and for BALB/c mice, immunization with B. melitensis induced much greater production of anti-GM1 ganglioside than GBS-associated C. jejuni. Flaccid limb weakness was observed in B. melitensis immunized mice. These results suggest that B. melitensis is a new etiological agent for GBS and that immunological responses between it and GBS-associated C. jejuni in the mouse model may be different.

  18. Two carbohydrate binding sites in the H(CC)-domain of tetanus neurotoxin are required for toxicity.

    PubMed

    Rummel, Andreas; Bade, Steffen; Alves, Jürgen; Bigalke, Hans; Binz, Thomas

    2003-02-21

    Tetanus neurotoxin binds via its carboxyl-terminal H(C)-fragment selectively to neurons mediated by complex gangliosides. We investigated the lactose and sialic acid binding pockets of four recently discovered potential binding sites employing site-directed mutagenesis. Substitution of residues in the lactose binding pocket drastically decreased the binding of the H(C)-fragment to immobilized gangliosides and to rat brain synaptosomes as well as the inhibitory action of recombinant full length tetanus neurotoxin on exocytosis at peripheral nerves. The conserved motif of S(1287)XWY(1290) em leader G(1300) assisted by N1219, D1222, and H1271 within the lactose binding site comprises a typical sugar binding pocket, as also present, for example, in cholera toxin. Replacement of the main residue of the sialic acid binding site, R1226, again caused a dramatic decline in binding affinity and neurotoxicity. Since the structural integrity of the H(C)-fragment mutants was verified by circular dichroism and fluorescence spectroscopy, these data provide the first biochemical evidence that two carbohydrate interaction sites participate in the binding and uptake process of tetanus neurotoxin. The simultaneous binding of one ganglioside molecule to each of the two binding sites was demonstrated by mass spectroscopy studies, whereas ganglioside-mediated linkage of native tetanus neurotoxin molecules was ruled out by size exclusion chromatography. Hence, a subsequent displacement of one ganglioside by a glycoprotein receptor is discussed.

  19. Sialylation regulates brain structure and function

    PubMed Central

    Yoo, Seung-Wan; Motari, Mary G.; Susuki, Keiichiro; Prendergast, Jillian; Mountney, Andrea; Hurtado, Andres; Schnaar, Ronald L.

    2015-01-01

    Every cell expresses a molecularly diverse surface glycan coat (glycocalyx) comprising its interface with its cellular environment. In vertebrates, the terminal sugars of the glycocalyx are often sialic acids, 9-carbon backbone anionic sugars implicated in intermolecular and intercellular interactions. The vertebrate brain is particularly enriched in sialic acid-containing glycolipids termed gangliosides. Human congenital disorders of ganglioside biosynthesis result in paraplegia, epilepsy, and intellectual disability. To better understand sialoglycan functions in the nervous system, we studied brain anatomy, histology, biochemistry, and behavior in mice with engineered mutations in St3gal2 and St3gal3, sialyltransferase genes responsible for terminal sialylation of gangliosides and some glycoproteins. St3gal2/3 double-null mice displayed dysmyelination marked by a 40% reduction in major myelin proteins, 30% fewer myelinated axons, a 33% decrease in myelin thickness, and molecular disruptions at nodes of Ranvier. In part, these changes may be due to dysregulation of ganglioside-mediated oligodendroglial precursor cell proliferation. Neuronal markers were also reduced up to 40%, and hippocampal neurons had smaller dendritic arbors. Young adult St3gal2/3 double-null mice displayed impaired motor coordination, disturbed gait, and profound cognitive disability. Comparisons among sialyltransferase mutant mice provide insights into the functional roles of brain gangliosides and sialoglycoproteins consistent with related human congenital disorders.—Yoo, S.-W., Motari, M. G., Susuki, K., Prendergast, J., Mountney, A., Hurtado, A., Schnaar, R. L. Sialylation regulates brain structure and function. PMID:25846372

  20. Use of influenza C virus glycoprotein HEF for generation of vesicular stomatitis virus pseudotypes.

    PubMed

    Hanika, Andrea; Larisch, Birthe; Steinmann, Eike; Schwegmann-Wessels, Christel; Herrler, Georg; Zimmer, Gert

    2005-05-01

    Influenza C virus contains two envelope glycoproteins: CM2, a putative ion channel protein; and HEF, a unique multifunctional protein that performs receptor-binding, receptor-destroying and fusion activities. Here, it is demonstrated that expression of HEF is sufficient to pseudotype replication-incompetent vesicular stomatitis virus (VSV) that lacks the VSV glycoprotein (G) gene. The pseudotyped virus showed characteristic features of influenza C virus with respect to proteolytic activation, receptor usage and cell tropism. Chimeric glycoproteins composed of HEF ectodomain and VSV-G C-terminal domains were efficiently incorporated into VSV particles and showed receptor-binding and receptor-destroying activities but, unlike authentic HEF, did not mediate efficient infection, probably because of impaired fusion activity. HEF-pseudotyped VSV efficiently infected polarized Madin-Darby canine kidney cells via the apical plasma membrane, whereas entry of VSV-G-complemented virus was restricted to the basolateral membrane. These findings suggest that pseudotyping of viral vectors with HEF might be useful for efficient apical gene transfer into polarized epithelial cells and for targeting cells that express 9-O-acetylated sialic acids.

  1. Role of sialidase in glycoprotein utilization by Tannerella forsythia.

    PubMed

    Roy, Sumita; Honma, Kiyonobu; Douglas, C W Ian; Sharma, Ashu; Stafford, Graham P

    2011-11-01

    The major bacterial pathogens associated with periodontitis include Tannerella forsythia. We previously discovered that sialic acid stimulates biofilm growth of T. forsythia, and that sialidase activity is key to utilization of sialoconjugate sugars and is involved in host-pathogen interactions in vitro. The aim of this work was to assess the influence of the NanH sialidase on initial biofilm adhesion and growth in experiments where the only source of sialic acid was sialoglycoproteins or human oral secretions. After showing that T. forsythia can utilize sialoglycoproteins for biofilm growth, we showed that growth and initial adhesion with sialylated mucin and fetuin were inhibited two- to threefold by the sialidase inhibitor oseltamivir. A similar reduction (three- to fourfold) was observed with a nanH mutant compared with the wild-type. Importantly, these data were replicated using clinically relevant serum and saliva samples as substrates. In addition, the ability of the nanH mutant to form biofilms on glycoprotein-coated surfaces could be restored by the addition of purified NanH, which we show is able to cleave sialic acid from the model glycoprotein fetuin and, much less efficiently, 9-O-acetylated bovine submaxillary mucin. These data show for the first time that glycoprotein-associated sialic acid is likely to be a key in vivo nutrient source for T. forsythia when growing in a biofilm, and suggest that sialidase inhibitors might be useful adjuncts in periodontal therapy.

  2. Thermodynamic stability and kinetic inertness of a Gd-DTPA bisamide complex grafted onto gold nanoparticles.

    PubMed

    Mogilireddy, Vijetha; Déchamps-Olivier, Isabelle; Alric, Christophe; Laurent, Gautier; Laurent, Sophie; Vander Elst, Luce; Muller, Robert; Bazzi, Rana; Roux, Stéphane; Tillement, Olivier; Chuburu, Françoise

    2015-01-01

    Gold nanoparticles coated by gadolinium (III) chelates (Au@DTDTPA) where DTDTPA is a dithiolated bisamide derivative of diethylenetriamine-N,N,N',N'',N''-pentaacetic acid (DTPA), constituted contrast agents for both X-ray computed tomography and magnetic resonance imaging. In an MRI context, highly stable Gd(3+) complexes are needed for in vivo applications. Thus, knowledge of the thermodynamic stability and kinetic inertness of these chelates, when grafted onto gold nanoparticles, is crucial since bisamide DTPA chelates are usually less suited for Gd(3+) coordination than DTPA. Therefore, these parameters were evaluated by means of potentiometric titrations and relaxivity measurements. The results showed that, when the chelates were grafted onto the nanoparticle, not only their thermodynamic stability but also their kinetic inertness were improved. These positive effects were correlated to the chelate packing at the nanoparticle surface that stabilized the corresponding Gd(3+) complexes and greatly enhanced their kinetic inertness.

  3. The appearance of newly identified intraocular lesions in Gaucher disease type 3 despite long-term glucocerebrosidase replacement therapy

    PubMed Central

    Sawicka-Gutaj, Nadia; Machaczka, Maciej; Kulińska-Niedziela, Izabela; Bernardczyk-Meller, Jadwiga; Gutaj, Paweł; Sowiński, Jerzy; Ruchała, Marek

    2016-01-01

    Background Gaucher disease (GD) is an autosomal recessive lipid storage disorder caused by the deficient activity of the lysosomal enzyme glucocerebrosidase. The presence of central nervous system disease is a hallmark of the neuronopathic forms of GD (types 2 and 3). Intraocular lesions (e.g. corneal clouding, retinal lesions, and vitreous opacities) have been infrequently reported in GD type 3 (GD3). Moreover, there are virtually no published data on the occurrence and natural course of intraocular lesions in GD3 patients treated with enzyme replacement therapy (ERT). Case presentation We describe the case of a 26-year-old Polish male with L444P homozygous GD3 (mutation c.1448T > C in the GBA1 gene) who developed fundus lesions despite 10 years of ERT. At the age of 23 years, a spectral domain optical coherence tomography (OCT) examination was performed which disclosed the presence of discrete lesions located preretinally, intraretinally in the nerve fiber layer, and in the vitreous body. A 3-year follow-up OCT examination has not shown any significant progression of the fundus lesions. Conclusions To the best of our knowledge, this is the first published report describing the occurrence of newly identified retinal and preretinal lesions occurring during long-term ERT in GD3. We recommend that a careful ophthalmic assessment, including a dilated fundus examination, should be included as part of annual follow-up in patients with GD3. Further studies are needed to understand the nature and clinical course of these changes and whether or not these intraocular findings have any predictive value in the context of neurologic and skeletal progression in GD3. PMID:27064303

  4. Lectin-mediated attachment of liposomes to cornea: influence on transcorneal drug flux

    SciTech Connect

    Schaeffer, H.E.; Breitfeller, J.M.; Krohn, D.L.

    1982-10-01

    A method to enhance retention of drug-bearing liposomes at the corneal surface under conditions of tear flow was investigated. Mixed brain gangliosides were incorporated into the membranes of phosphatidyl choline liposomes to provide receptor sites for wheat germ agglutinin, a plant lectin that binds strongly to both human and rabbit corneal epithelium. Ganglioside-containing liposomes showed a 2.5-fold increase in their binding to rabbit cornea in vitro when corneas were pretreated with wheat germ agglutinin (500 micrograms/ml), suggesting that the lectin mediates specific binding of these liposomes to the corneal surface. In addition, under conditions of continuous tear flow (1 ml/hr), ganglioside-containing liposomes with entrapped carbachol significantly enhanced carbachol flux across isolated rabbit corneas pretreated with wheat germ agglutinin 90 min after drug delivery. The data support the potential use of liposomes as a vehicle for topical drug flux enhancement.

  5. Membrane raft disruption promotes axonogenesis in n2a neuroblastoma cells.

    PubMed

    Petro, Kimberly A; Schengrund, Cara-Lynne

    2009-01-01

    Membrane rafts are discrete microdomains found in cell membranes that contain cholesterol and glycosphingolipids such as gangliosides. As cholesterol is a major component of membrane rafts, its sequestration by the polyene filipin can be used to disrupt them. In previous work we observed that membrane raft disruption by filipin treatment of murine neuroblastoma N2a cells led to changes in expression of cell processes. In this study, we determined the type of process formation induced by filipin treatment as well as whether their expression was accompanied by changes in ganglioside content or subcellular distribution. The results indicate that the processes formed were axonal in nature and their expression was accompanied by changes in both ganglioside content as well as the subcellular localization of GM1.

  6. The beta-hexosaminidase deficiency disorders: development of a clinical paradigm in the mouse.

    PubMed

    Tifft, C J; Proia, R L

    1997-12-01

    Tay-Sachs disease and Sandhoff disease are severe neurodegenerative disorders caused by a deficiency of beta-hexosaminidase A and resultant accumulation of its substrate, GM2 ganglioside, in neuronal lysosomes. The three clinical forms of the disorders (infantile, juvenile and adult) are of varying severity and onset, and have been correlated with the amount of residual GM2 ganglioside-degrading activity present in patients' cells. Through targeted disruption of the murine beta-hexosaminidase genes in embryonic stem cells, we have developed a set of mice that vary in their GM2 ganglioside-degrading capacity and exhibit many of the clinical features of the human diseases. These mice are valuable for the study of pathogenic mechanisms and for devising novel therapeutic strategies in these disorders.

  7. Association of endogenous substrate with solubilized bovine brain sialidase.

    PubMed

    Schengrund, C L; Repman, M A

    1986-01-01

    Nonidet P40 solubilized up to 90% of the sialidase, active towards added ganglioside substrate, that was associated with the total membrane fraction prepared from gray matter of bovine brains. Solubilized sialidase acted upon endogenous substrate (sialic acid containing compounds solubilized with the enzyme), hydrolyzing approximately 50% of the readily available sialosyl residues within 20 min. During a 2-hr reaction time 80% of the polysialylated gangliosides solubilized with the enzyme were acted upon. A 20-min lag was observed before sialidase acted upon added ganglioside substrate. The lag could be reduced to less than 2 min when the enzyme was allowed to act on endogenous substrate prior to exposure to exogenous substrate, suggesting that the solubilized enzyme acted preferentially on endogenous substrate. A protease inhibitor prevented much of the 86% loss of activity towards added substrate that was seen when the enzyme was stored at 4 degrees C for 6 days; activity towards endogenous substrate decreased only 34%.

  8. Probing Biological Processes on Supported Lipid Bilayers with Single-Walled Carbon Nanotube Field-Effect Transistors

    NASA Astrophysics Data System (ADS)

    Zhou, Xinjian; Moran-Mirabal, Jose Manuel; Craighead, Harold; McEuen, Paul

    2006-03-01

    We have formed supported lipid bilayers (SLBs) by small unilamellar vesicle fusion on substrates containing single-walled carbon nanotube field-effect transistors (SWNT-FETs). We are able to detect the self-assembly of SLBs electrically with SWNT-FETs since their threshold voltages are shifted by this event. The SLB fully covers the NT surface and lipid molecules can diffuse freely in the bilayer surface across the NT. To study the interactions of important biological entities with receptors imbedded within the membrane, we have also integrated a membrane protein, GT1b ganglioside, in the bilayer. While bare gangliosides can diffuse freely across the NT, interestingly the NT acts as a diffusion barrier for the gangliosides when they are bound with tetanus toxin. This experiment opens the possibility of using SWNT-FETs as biosensors for label-free detection.

  9. Mechanism for the thermal dependence of the Cr to Nd energy transfer in garnets

    NASA Technical Reports Server (NTRS)

    Armagan, Guzin; Di Bartolo, Baldassare

    1988-01-01

    The temperature dependence of the Cr-Nd energy transfer is found to be due to the thermal variation of the radiative decay probability of Cr. The validity of this conjecture is checked in the Gd3Sc2Ga3O12 and CaMg2Y2Ge3O12 crystals. It is also found that above 200 K, the nonradiative energy transfer rate from Cr to Nd is greater in Gd3Sc2Ga3O12 than in CaMg2Y2Ge3O12.

  10. Gd-Si Oxide Nanoparticles as Contrast Agents in Magnetic Resonance Imaging

    PubMed Central

    Cabrera-García, Alejandro; Vidal-Moya, Alejandro; Bernabeu, Ángela; Pacheco-Torres, Jesús; Checa-Chavarria, Elisa; Fernández, Eduardo; Botella, Pablo

    2016-01-01

    We describe the synthesis, characterization and application as contrast agents in magnetic resonance imaging of a novel type of magnetic nanoparticle based on Gd-Si oxide, which presents high Gd3+ atom density. For this purpose, we have used a Prussian Blue analogue as the sacrificial template by reacting with soluble silicate, obtaining particles with nanorod morphology and of small size (75 nm). These nanoparticles present good biocompatibility and higher longitudinal and transversal relaxivity values than commercial Gd3+ solutions, which significantly improves the sensitivity of in vivo magnetic resonance images. PMID:28335240

  11. Optical Investigations of Rare-Earth Orthochromites. III. GdCrO3 and Summary of the R' Band in RCrO3

    NASA Astrophysics Data System (ADS)

    Kojima, Norimichi; Tsujikawa, Ikuji; Tsushima, Kuniro

    1985-12-01

    Optical absorption spectrum corresponding to the 4A2g→2Eg transition of Cr3+ in GdCrO3 was studied. The R' band was observed in the lower energy side of the R exciton band. The temperature and magnetic field dependences of the R' band imply that the R' band is the combined excitation of a Cr3+ exciton and a Gd3+ spin flip induced by the isotropic part of the Cr3+-Gd3+ exchange interaction. As the summary of the successive papers, the classification of the R' band in RCrO3(R=Yb, Tm, Er, No, Dy, Tb and Gd) was undertaken.

  12. Analytical Interference in Serum Iron Determination Reveals Iron Versus Gadolinium Transmetallation With Linear Gadolinium-Based Contrast Agents

    PubMed Central

    Fretellier, Nathalie; Poteau, Nathalie; Factor, Cécile; Mayer, Jean-François; Medina, Christelle; Port, Marc; Idée, Jean-Marc; Corot, Claire

    2014-01-01

    Objectives The purposes of this study were to evaluate the risk for analytical interference with gadolinium-based contrast agents (GBCAs) for the colorimetric measurement of serum iron (Fe3+) and to investigate the mechanisms involved. Materials and Methods Rat serum was spiked with several concentrations of all molecular categories of GBCAs, ligands, or “free” soluble gadolinium (Gd3+). Serum iron concentration was determined by 2 different colorimetric methods at pH 4.0 (with a Vitros DT60 analyzer or a Cobas Integra 400 analyzer). Secondly, the cause of interference was investigated by (a) adding free soluble Gd3+ or Mn2+ to serum in the presence of gadobenic acid or gadodiamide and (b) electrospray ionization mass spectrometry. Results Spurious decrease in serum Fe3+ concentration was observed with all linear GBCAs (only with the Vitros DT60 technique occurring at pH 4.0) but not with macrocyclic GBCAs or with free soluble Gd3+. Spurious hyposideremia was also observed with the free ligands present in the pharmaceutical solutions of the linear GBCAs gadopentetic acid and gadodiamide (ie, diethylene triamine pentaacetic acid and calcium-diethylene triamine pentaacetic acid bismethylamide, respectively), suggesting the formation of Fe-ligand chelate. Gadobenic acid-induced interference was blocked in a concentration-dependent fashion by adding a free soluble Gd3+ salt. Conversely, Mn2+, which has a lower affinity than Gd3+ and Fe3+ for the ligand of gadobenic acid (ie, benzyloxypropionic diethylenetriamine tetraacetic acid), was less effective (interference was only partially blocked), suggesting an Fe3+ versus Gd3+ transmetallation phenomenon at pH 4.0. Similar results were observed with gadodiamide. Mass spectrometry detected the formation of Fe-ligand with all linear GBCAs tested in the presence of Fe3+ and the disappearance of Fe-ligand after the addition of free soluble Gd3+. No Fe-ligand chelate was found in the case of the macrocyclic GBCA gadoteric

  13. Effect of protein-encapsulation on thermal structural stability of liposome composed of glycosphingolipid/cholesterol/phospholipid.

    PubMed

    Hirai, Mitsuhiro; Sato, Shoki; Kimura, Ryota; Hagiwara, Yoshihiko; Kawai-Hirai, Rika; Ohta, Noboru; Igarashi, Noriyuki; Shimizu, Nobutaka

    2015-02-26

    We have studied the thermal structural stability of liposomes encapsulating proteins by using synchrotron radiation small- and wide-angle X-ray scattering (SR-SWAXS). Liposomes are known to be effective drug-delivery systems (DDSs) because they can reduce drug toxicity due to biodegradability and biocompatibility and can offer promising carriers of various types of drugs. However, in spite of numerous studies of liposomes, physicochemical characteristics of liposomes entrapping proteins are rarely known. The liposome studied is characterized by the lipid composition (mixture of acidic glycosphingolipid (ganglioside)/cholesterol/phospholipid). Gangliosides are one of the major constituents of so-called lipid rafts playing the role of a platform of cell-signaling. We have found that the encapsulation of proteins elevates the thermal transition temperature of the liposome membrane and suppresses the deformation of its shape. The present results suggest that not only membrane proteins, but also water-soluble proteins affect liposome stability through the revalence between osmotic pressure and membrane elasticity. In addition, we have found the presence of the size-effect depending on the molar content of gangliosides in the liposome, indicating the ability of ganglioside molecule controlling both the size and effective surface charge of the liposome. The present results would have significance from two different points of view. One is the confinement effect of proteins within a limited space like cell, and the other is a stability of a new type of DDS using gangliosides. Due to the intrinsic properties, gangliosides are expected to be promising agents for targeting and long-circulation properties of liposomal DDSs.

  14. Sialosyl-fucosyl Poly-LacNAc without the sialosyl-Lex epitope as the physiological myeloid cell ligand in E-selectin-dependent adhesion: studies under static and dynamic flow conditions.

    PubMed

    Handa, K; Stroud, M R; Hakomori, S

    1997-10-14

    The majority of E- and P-selectin ligands in leukocytes and myelocytic or monocytic leukemia cells are carried by transmembrane glycoproteins having a tandem repeat mucin-like domain through which O-linked carbohydrate ligands are carried. However, determination of structure and adhesive function of carbohydrates in glycoproteins is extremely difficult because of the extensive structural heterogeneity and the scarcity of material for functional analysis. We have overcome this difficulty through use of poly-LacNAc gangliosides isolated from a large quantity of ( approximately 1.2 L packed) HL60 cells [Stroud, M. R., Handa, K., Salyan, M. E. K., Ito, K., Levery, S. B., Hakomori, S., Reinhold, B. B., & Reinhold, V. N. (1996) Biochemistry 35, 758-769, 770-778]. We identified two major types of poly-LacNAc gangliosides without the sialosyl-Lex epitope as being capable of binding to E-selectin: (i) those having a single alpha1-->3 fucosylation at internal GlcNAcs but not at the penultimate GlcNAc and (ii) those having double alpha1-->3 fucosylation at internal GlcNAcs, excluding the penultimate GlcNAc. Gangliosides from group i above did not show any adhesion under static conditions, but showed strong adhesion under dynamic flow conditions. Gangliosides from group ii above showed adhesion under both static and dynamic conditions, as did sialosyl-Lex (SLex)-containing structures in previous studies. However, SLex-containing poly-LacNAc gangliosides are virtually absent or present in only trace quantities in leukocytes and HL60 cells. Poly-LacNAc gangliosides from groups i and ii above, lacking SLex structure, are the major membrane components of leukocytes and HL60 cells. These carbohydrates, bound to lipid or to protein, may therefore be the physiological epitope for E-selectin-dependent binding of these cells, particularly under dynamic flow conditions.

  15. GM2A — EDRN Public Portal

    Cancer.gov

    GM2A, a small glycolipid transport protein, acts as a substrate specific co-factor for the lysosomal enzyme beta-hexosaminidase A. Beta-hexosaminidase A, together with GM2 ganglioside activator, catalyzes the degradation of the ganglioside GM2, and other molecules containing terminal N-acetyl hexosamines. Mutations in this gene result in GM2-gangliosidosis type AB or the AB variant of Tay-Sachs disease. Alternative splicing of the GM2A gene results in multiple transcript variants. In post-translational modification the serines in positions 32 and 33 are absent in 80% of the sequenced protein.

  16. Immunological reaction of the demyelinating Semliki Forest virus with immune serum to glycolipids and its possible importance to central nervous system viral auto-immune disease.

    PubMed

    Webb, H E; Mehta, S; Gregson, N A; Leibowitz, S

    1984-01-01

    The avirulent demyelinating strain A7(74) of Semliki Forest virus after passage through mouse brain in vivo and mouse brain cell cultures has been shown to react immunologically with immune sera against galactocerebroside, glucocerebroside, total ganglioside and GT1b ganglioside but not against myelin or sulphatide . Semliki Forest virus is known to take host membrane glycolipid into its coat. The importance of the findings is discussed in relation to the production of a possible anti-brain cell auto-immune phenomenon and its implication in a disease such as multiple sclerosis.

  17. Synthesis, crystal structure and fluorescence properties of terbium complexes with phenoxyacetic acid and 2,4,6-tris-(2-pyridyl)-s-triazine.

    PubMed

    Wang, Zhong-Xia; Wang, Ai-Ling; Wei, Xiao-Yan; Qu, Yan-Rong; Yue, Bin; Kang, Jie; Chu, Hai-Bin; Zhao, Yong-Liang

    2015-09-01

    Two complexes of Tb(3+), Gd(3+) /Tb(3+) and one heteronuclear crystal Gd(3+)/Tb(3+) with phenoxyacetic acid (HPOA) and 2,4,6-tris-(2-pyridyl)-s-triazine (TPTZ) have been synthesized. Elemental analysis, rare earth coordination titration, inductively coupled plasma atomic emission spectrometry (ICP-AES) and thermogravimetric analysis-differential scanning calorimetry (TG-DSC) analysis show that the two complexes are Tb2 (POA)6 (TPTZ)2 · 6H2O and TbGd(POA)6 (TPTZ)2 · 6H2O, respectively. The crystal structure of TbGd(POA)6 (TPTZ)2 · 2CH3OH was determined using single-crystal X-ray diffraction. The monocrystal belongs to the triclinic system with the P-1 space group. In particular, each metal ion is coordinately bonded to three nitrogen atoms of one TPTZ and seven oxygen atoms of three phenoxyacetic ions. Furthermore, there exist two coordinate forms between C6H5OCH2COO(-) and the metal ions in the crystal. One is a chelating bidentate, the other is chelating and bridge coordinating. Fluorescence determination shows that the two complexes possess strong fluorescence emissions. Furthermore, the fluorescence intensity of the Gd(3+)/Tb(3+) complex is much stronger than that of the undoped complex, which may result from a decrease in the concentration quench of Tb(3+) ions, and intramolecular energy transfer from the ligands coordinated with Gd(3+) ions to Tb(3+) ions.

  18. Facile Preparation of a New Gadofullerene-Based Magnetic Resonance Imaging Contrast Agent with High 1H Relaxivity

    PubMed Central

    Shu, Chunying; Corwin, Frank D.; Zhang, Jianfei; Chen, Zhijian; Reid, Jonathan E.; Sun, Minghao; Xu, Wei; Sim, Jae Hyun; Wang, Chunru; Fatouros, Panos P.; Esker, Alan R.; Gibson, Harry W.; Dorn, Harry C.

    2009-01-01

    A new magnetic resonance imaging (MRI) contrast agent based on the trimetallic nitride templated (TNT) metallofullerene, Gd3N@C80, was synthesized by a facile method in high yield. The observed longitudinal and transverse relaxivities, r1 and r2, for water hydrogens in the presence of the water-soluble gadofullerene 2, Gd3N@C80(OH)~26(CH2CH2COOM)~16 (M = Na or H), are 207 and 282 mM-1s-1 (per C80 cage) at 2.4 T, respectively; these values are 50 times larger than those of Gd3+ poly(aminocarboxylate) complexes, such as commercial Omniscan® and Magnevist®. This high 1H relaxivity for this new hydroxylated and carboxylated gadofullerene derivative provides high signal enhancement at significantly lower Gd concentration as demonstrated by in vitro and in vivo MRI studies. Dynamic light scattering data reveal a unimodal size distribution with an average hydrodynamic radius of ca. 78 nm in pure water (pH = 7), which is significantly different from other hydroxylated or carboxylated fullerene and metallofullerene derivatives reported to date. Agarose gel infusion results indicate that the gadofullerene 2 displayed diffusion properties different from that of commercial Omniscan® and those of PEG5000 modified Gd3N@C80. The reactive carboxyl functionality present on this highly efficient contrast agent may also serve as a precursor for biomarker tissue-targeting purposes. PMID:19445504

  19. Experimental optimum design and luminescence properties of NaY(Gd)(MoO4)2:Er3+ phosphors

    NASA Astrophysics Data System (ADS)

    Jia-Shi, Sun; Sai, Xu; Shu-Wei, Li; Lin-Lin, Shi; Zi-Hui, Zhai; Bao-Jiu, Chen

    2016-06-01

    Three-factor orthogonal design (OD) of Er3+/Gd3+/T (calcination temperature) is used to optimize the luminescent intensity of NaY(Gd)(MoO4)2:Er3+ phosphor. Firstly, the uniform design (UD) is introduced to explore the doping concentration range of Er3+/Gd3+. Then OD and range analysis are performed based on the results of UD to obtain the primary and secondary sequence and the best combination of Er3+, Gd3+, and T within the experimental range. The optimum sample is prepared by the high temperature solid state method. Photoluminescence excitation and emission spectra of the optimum sample are detected. The intense green emissions (530 nm and 550 nm) are observed which originate from Er3+ 2H11/2→ 4I15/2 and 4S3/2→4I15/2, respectively. Thermal effect is investigated in the optimum NaY(Gd3+)(MoO4)2:Er3+ phosphors, and the green emission intensity decreases as temperature increases. Project supported by Education Reform Fund of Dalian Maritime University, China (Grant No. 2015Y37), the Natural Science Foundation of Liaoning Province, China (Grant Nos. 2015020190 and 2014025010), the Open Fund of the State Key Laboratory on Integrated Optoelectronics, China (Grant No. IOSKL2015KF27), and the Fundamental Research Funds for the Central Universities, China (Grant No. 3132016121).

  20. Effects of gadolinium and tetrodotoxin on the response of slowly adapting type I mechanoreceptors to mechanical stimulation in frog dorsal skin.

    PubMed

    Takeda, Mamoru; Nishikawa, Toshimi; Sato, Sumie; Aiyama, Shigeo; Matsumoto, Shigeji

    2003-12-01

    To elucidate the excitatory mechanism of mechanoreceptors innervating the frog skin, we examined the effects of gadolinium (Gd3+) and tetrodotoxin (TTX) on the response of single-unit activity of slowly adapting type I mechanoreceptors to mechanical stimulation topically applied to the receptive field (RF). Recordings were made from 46 fibers responding to mechanical stimulation with von Frey hairs, which caused an irregular firing pattern with slow adaptation. Application of a mechanically gated channel blocker, Gd3+ (30 microM), and a Na+ channel blocker, TTX (3 microM), caused the suppression of discharge rates, which was characterized by the conversion of a slowly adapting to a rapidly adapting discharge pattern. The administration of a high-voltage-activated (HVA) Ca2+ channel blocker, Cd2+ (100 microm), inhibited the unit discharge and caused the conversion of a slowly adapting to a rapidly adapting discharge pattern. Tonic discharges evoked by anodal electrical stimulation were inhibited by the application of Gd3+ or TTX. Electron microscopic examination showed that the cytoplasm of Merkel cells seen in the RF contained numerous Merkel granules. These results suggest that the excitatory mechanism of frog cutaneous mechanoreceptors may be mediated by the activation of Gd(3+)-sensitive stretch-activated channels in the Merkel cell-neurite complex, which are related to the Na+ influx via voltage-gated Na+ channels and/or the Ca2+ influx through HVA Ca2+ channels.

  1. Encapsulation of α-Particle–Emitting 225Ac3+ Ions Within Carbon Nanotubes

    PubMed Central

    Matson, Michael L.; Villa, Carlos H.; Ananta, Jeyarama S.; Law, Justin J.; Scheinberg, David A.; Wilson, Lon J.

    2016-01-01

    225Ac3+ is a generator of α-particle–emitting radionuclides with 4 net α-particle decays that can be used therapeutically. Targeting 225Ac3+ by use of ligands conjugated to traditional bifunctional chelates limits the amount of 225Ac3+ that can be delivered. Ultrashort, single-walled carbon nanotubes (US-tubes), previously demonstrated as sequestering agents of trivalent lanthanide ions and small molecules, also successfully incorporate 225Ac3+. Methods Aqueous loading of both 225Ac3+ ions and Gd3+ ions via bath sonication was used to construct 225Ac@gadonanotubes (225Ac@GNTs). The 225Ac@GNTs were subsequently challenged with heat, time, and human serum. Results US-tubes internally loaded with both 225Ac3+ ions and Gd3+ ions show 2 distinct populations of 225Ac3+ ions: one rapidly lost in human serum and one that remains bound to the US-tubes despite additional challenge with heat, time, and serum. The presence of the latter population depended on cosequestration of Gd3+ and 225Ac3+ ions. Conclusion US-tubes successfully sequester 225Ac3+ ions in the presence of Gd3+ ions and retain them after a human serum challenge, rendering 225Ac@GNTs candidates for radioimmunotherapy for delivery of 225Ac3+ ions at higher concentrations than is currently possible for traditional ligand carriers. PMID:25931476

  2. Metal-promoted synthesis, characterization, crystal structure and RNA cleavage ability of 2,6-diacetylpyridine bis(2-aminobenzoylhydrazone) lanthanide complexes.

    PubMed

    Kozłowski, Michał; Kierzek, Ryszard; Kubicki, Maciej; Radecka-Paryzek, Wanda

    2013-09-01

    New 2,6-diacetylpyridine bis(2-aminobenzoylhydrazone) lanthanide complexes were formed in the metal-induced one-step [1+2] condensation reaction between 2,6-diacetylpyridine and 2-aminobenzoylhydrazide in the presence of lanthanide (La(3+), Pr(3+), Nd(3+), Sm(3+), Eu(3+), Gd(3+), Tb(3+), Dy(3+), Ho(3+), Er(3+), Tm(3+) or Yb(3+)) nitrates as template agents. The analytical and spectral characterizations of all the compounds were correlated with the single crystal X-ray structural determination of Eu(3+), Gd(3+), Tb(3+), Dy(3+) and Er(3+) nitrate complexes. The Eu(3+), Gd(3+), Tb(3+)and Dy(3+) complexes of pentadentate 2,6-diacetylpyridine bis(2-aminobenzoylhydrazone) with the N3O2 set of donor atoms display a high and relatively rare coordination number of 11, whereas the Er(3+) ion complex is 9-coordinated, which is consistent with the lanthanide contraction phenomenon. The scission of 21-mer RNA was assessed for Eu(3+), Gd(3+) and Tb(3+) nitrate complexes. Lanthanide complexes not covalently attached to the oligonucleotide are able to cleave RNA at the target site in a sequence-selective or non-selective manner depending on the presence of protecting 12-mer 2'OMe RNA.

  3. Age-dependent changes in diastolic Ca(2+) and Na(+) concentrations in dystrophic cardiomyopathy: Role of Ca(2+) entry and IP3.

    PubMed

    Mijares, Alfredo; Altamirano, Francisco; Kolster, Juan; Adams, José A; López, José R

    2014-10-03

    Duchenne muscular dystrophy (DMD) is a lethal X-inherited disease caused by dystrophin deficiency. Besides the relatively well characterized skeletal muscle degenerative processes, DMD is also associated with a dilated cardiomyopathy that leads to progressive heart failure at the end of the second decade. The aim of the present study was to characterize the diastolic Ca(2+) concentration ([Ca(2+)]d) and diastolic Na(+) concentration ([Na(+)]d) abnormalities in cardiomyocytes isolated from 3-, 6-, 9-, and 12-month old mdx mice using ion-selective microelectrodes. In addition, the contributions of gadolinium (Gd(3+))-sensitive Ca(2+) entry and inositol triphosphate (IP3) signaling pathways in abnormal [Ca(2+)]d and [Na(+)]d were investigated. Our results showed an age-dependent increase in both [Ca(2+)]d and [Na(+)]d in dystrophic cardiomyocytes compared to those isolated from age-matched wt mice. Gd(3+) treatment significantly reduced both [Ca(2+)]d and [Na(+)]d at all ages. In addition, blockade of the IP3-pathway with either U-73122 or xestospongin C significantly reduced ion concentrations in dystrophic cardiomyocytes. Co-treatment with U-73122 and Gd(3+) normalized both [Ca(2+)]d and [Na(+)]d at all ages in dystrophic cardiomyocytes. These data showed that loss of dystrophin in mdx cardiomyocytes produced an age-dependent intracellular Ca(2+) and Na(+) overload mediated at least in part by enhanced Ca(2+) entry through Gd(3+) sensitive transient receptor potential channels (TRPC), and by IP3 receptors.

  4. Exploratory Development on Laser and Optical Materials.

    DTIC Science & Technology

    Judd-Ofelt theory, Quantum efficiencies); Laser materials evaluation; Studies of rare-earth doped CdF2, SrF2 , and BaF2 -- (Electroluminescence of semiconducting CdF2, Analyses of the optical spectra of Gd(3+) and Ce(3+)).

  5. Development of scintillating screens based on the single crystalline films of Ce doped (Gd,Y)3(Al,Ga,Sc)5O12 multi-component garnets

    NASA Astrophysics Data System (ADS)

    Zorenko, Yuriy; Gorbenko, Vitaliy; Savchyn, Volodymyr; Zorenko, Tanya; Fedorov, Alexander; Sidletskiy, Oleg

    2014-09-01

    The paper is dedicated to development of scintillators based on single crystalline films of Ce doped (Gd,Y)3(Al,Ga,Sc)5O12 multi-component garnets onto Gd3Ga5O12 substrates using the liquid phase epitaxy method.

  6. Effect of gadolinium on the ryanodine receptor/sarcoplasmic reticulum calcium release channel of skeletal muscle.

    PubMed

    Sárközi, Sándor; Szegedi, Csaba; Lukács, Balázs; Ronjat, Michel; Jóna, István

    2005-01-01

    The effect of gadolinium ions on the sarcoplasmic reticulum (SR) calcium release channel/ryanodine receptor (RyR1) was studied using heavy SR (HSR) vesicles and RyR1 isolated from rabbit fast twitch muscle. In the [(3)H]ryanodine binding assay, 5 microM Gd(3+) increased the K(d) of the [(3)H]ryanodine binding of the vesicles from 33.8 nM to 45.6 nM while B(max), referring to the binding capacity, was not affected significantly. In the presence of 18 nM[(3)H]ryanodine and 100 microM free Ca(2+), Gd(3+) inhibited the binding of the radiolabeled ryanodine with an apparent K(d) value of 14.7 microM and a Hill coefficient of 3.17. In (45)Ca(2+) experiments the time constant of (45)Ca(2+) efflux from HSR vesicles increased from 90.9 (+/- 11.1) ms to 187.7 (+/- 24.9) ms in the presence of 20 microM gadolinium. In single channel experiments gadolinium inhibited the channel activity from both the cytoplasmic (cis) (IC(50) = 5.65 +/- 0.33 microM, n(Hill) = 4.71) and the luminal (trans) side (IC(50) = 5.47 +/- 0.24 microM, n(Hill) = 4.31). The degree of inhibition on the cis side didn't show calcium dependency in the 100 microM to 1 mM Ca(2+) concentration range which indicates no competition with calcium on its regulatory binding sites. When Gd(3+) was applied at the trans side, EGTA was present at the cis side to prevent the binding of Gd(+3) to the cytoplasmic calcium binding regulatory sites of the RyR1 if Gd(3+) accidentally passed through the channel. The inhibition of the channel did not show any voltage dependence, which would be the case if Gd(3+) exerted its effect after getting to the cis side. Our results suggest the presence of inhibitory binding sites for Gd(3+) on both sides of the RyR1 with similar Hill coefficients and IC(50) values.

  7. Electrospray mass spectrometry of NeuAc oligomers associated with the C fragment of the tetanus toxin

    SciTech Connect

    Prieto, M C; Whittal, R M; Baldwin, M A; Burlingame, A L; Balhorn, R

    2005-04-03

    The Clostridial neurotoxins, botulinum and tetanus, gain entry into neuronal cells by protein recognition involving cell specific binding sites. The sialic or N-acetylneuraminic acid (NeuAc) residues of gangliosides attached to the surface of motor neurons are the suspected recognition and interaction points with Clostridial neurotoxins, although not necessarily the only ones. We have used electrospray ionization mass spectrometry (ESIMS) to examine formation of complexes between the tetanus toxin C fragment, or targeting domain, and carbohydrates containing NeuAc groups to determine how NeuAc residues contribute to ganglioside binding. ESI-MS was used to rapidly and efficiently measure dissociation constants for a number of related NeuAc-containing carbohydrates and NeuAc oligomers, information that has helped identify the structural features of gangliosides that determine their binding to tetanus toxin. The strength of the interactions between the C fragment and (NeuAc){sub n}, are consistent with the topography of the targeting domain of tetanus toxin and the nature of its carbohydrate binding sites. The results suggest that the targeting domain of tetanus toxin contains two binding sites that can accommodate NeuAc (or a dimer). This study also shows that NeuAc must play an important role in ganglioside binding and molecular recognition, a process critical for normal cell function and one frequently exploited by toxins, bacteria and viruses to facilitate their entrance into cells.

  8. IgM binding to sialosyllactosaminylparagloboside in a patient with polyradiculoneuropathy due to Mycoplasma pneumoniae infection.

    PubMed

    Inuzuka, T; Miyatani, N; Baba, H; Tanaka, M; Tanaka, K; Sato, S; Nakamura, K; Miyatake, T

    1988-07-01

    IgM in serum without paraprotein in a patient with polyradiculoneuropathy due to a Mycoplasma pneumoniae infection reacted specifically with a ganglioside, sialosyllactosaminylparagroboside (SLPG), in a human peripheral nerve on a thin-layer chromatogram plate by an immunostaining technique. This finding suggests the possibility that anti-SLPG antibody in the patient's serum may play a role in the pathogenesis of neuropathy.

  9. In Vivo Phase Variation and Serologic Response to Lipooligosaccharide of Campylobacter jejuni i