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Avadhesha Surolia - One of the best experts on this subject based on the ideXlab platform.
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Comprehensive analysis of α 2-3-linked sialic acid specific Maackia amurensis leukagglutinin reveals differentially occupied N-glycans and C-terminal processing.
International journal of biological macromolecules, 2016Co-Authors: Gnanesh Kumar B.s, Avadhesha SuroliaAbstract:Seeds of Maackia amurensis constitutes two sialic acid specific agglutinins known as leukagglutinin and hemagglutinin. Maackia amurensis leukagglutinin (MAL) recognizes alpha 12-3-linked sialic acid present mainly in N-glycans and composed of two disulfide linked monomers. It exhibits potential N-glycosylation sites (four PNGs) which have been assumed to undergo differential occupancy. In this study we have characterized the site specific macro- and microheterogeneity of monomers in detail by analysing N-glycopeptides and peptides through liquid chromatography coupled to ion trap mass spectrometer in MS3 mode (LC-MSn). We observed the presence of mainly paucimannose N-glycans at Asn(61), Asn(113) and Asn(191) whereas a high mannose type with varying Man(5-9) occurs at Asn(179). Interestingly Asn(179) and Asn(191) exhibited differential occupancy which was evident by the presence of non-glycosylated peptides. This has contributed to the difference in molecular mass of monomers upon SDS-PAGE. Further the presence of disulfide linked peptides confirmed the covalent linkage of monomers which also undergoes uniform C-terminal processing. (C) 2016 Elsevier B.V. All rights reserved.
Tamas F Freund - One of the best experts on this subject based on the ideXlab platform.
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the supramammillary nucleus innervates cholinergic and gabaergic neurons in the medial septum diagonal band of broca complex
Neuroscience, 1997Co-Authors: Zsolt Borhegyi, Laszlo Acsady, Zsofia Magloczky, Tamas F FreundAbstract:In the present study, the connectivity between two subcortical nuclei involved in hippocampal theta activity, the supramammillary nucleus and the medial septum-diagonal band of Broca complex, was examined. Targets of the supramammillary afferents in the medial septum-diagonal band of Broca complex were identified by combining anterograde transport of Phaseolus vulgaris leucoagglutinin with immunostaining for putative postsynaptic neurons, i.e. for parvalbumin and choline acetyltransferase that are known to label the GABAergic and cholinergic neurons, respectively, of the medial septum-diagonal band of Broca complex. Double retrograde transport experiments using the tracers horseradish peroxidase and wheat germ agglutinin-conjugated colloidal gold were employed to identify supramammillary neurons that project both to the hippocampus and the medial septum-diagonal band of Broca complex. Phaseolus vulgaris leucoagglutinin injections into the supramammillary nucleus of the rat resulted in dense fibre and terminal labelling in the medial septum-diagonal band of Broca complex. Labelled terminals formed asymmetric synapses mainly on distal dendrites of medial septal neurons. Proximal dendrites and somata were rarely contacted. The supramammillary afferents showed no target selectivity for a particular cell type; they innervated both cholinergic and GABAergic cells. Occasionally, perisomatic, basket-like terminals of supramammillary origin were found around parvalbumin-containing neurons. Double-retrograde experiments revealed that at least 25% of the supramammillo-hippocampal cells also projected to the medial septum-diagonal band of Broca. These data suggest that the nucleus, known to modulate the hippocampal electrical activity directly by the supramammillo-hippocampal pathway, also has the potential for an indirect action via the innervation of both the GABAergic and cholinergic septohippocampal neurons. This dual modulation may originate, at least in part, from the same population of supramammillary neurons.
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calretinin is present in non pyramidal cells of the rat hippocampus iii their inputs from the median raphe and medial septal nuclei
Neuroscience, 1993Co-Authors: Laszlo Acsady, K Halasy, Tamas F FreundAbstract:The subcortical innervation of a recently described subpopulation of non-pyramidal neurons, containing the calcium binding protein, calretinin, was investigated in the rat hippocampus using the anterograde tracer Phaseolus vulgaris-leucoagglutinin and double immunocytochemistry for calretinin and serotonin at the light and electron microscopic levels. Our results show that the GABAergic component of the septohippocampal pathway and the serotonergic raphe afferents establish multiple synaptic contacts with the calretinin-immunoreactive interneurons. The majority of the targets of both pathways were spine-free calretinin neurons known to innervate the dendritic region of the principal cells, but the GABAergic septal pathway was found to terminate also on the spiny neurons of stratum lucidum of the CA3 region and in the dentate hilus. The present results demonstrate that the serotonergic raphe-hippocampal and the GABAergic septo-hippocampal pathways are able to modulate dendritic inhibition of principal cells via calretinin-containing GABAergic interneurons.
Ha Hyung Kim - One of the best experts on this subject based on the ideXlab platform.
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effects of high mannose type glycans of maackia amurensis Leukoagglutinin on sialic acid binding activity
한국당과학회 학술대회, 2016Co-Authors: Hye Seong Hwang, Heajin Park, Jihye Kim, Haesung Kim, Jai Yeon Choi, Ha Hyung KimAbstract:Maackia amurensis Leukoagglutinin (MAL) is a glycoprotein and sialic acid-binding lectin that is used widely in the detection and characterization of sialoglycoconjugates and human cancer cells. However, its N-linked glycan structure and role have yet to be determined. The N-linked glycans were analyzed using high-performance liquid chromatography with matrix assisted laser desorption/ionization time-of-flight mass spectrometry, and the secondary structure was investigated using circular dichroismanalysis. A hemagglutination assay was performed. Furthermore, surface plasmon resonance analysis, and fluorescence microscopy and fluorescence-activated cell-sorting analysiswere conducted to assess the sialoglycoprotein-binding ability and its usefulness in the detection of human breast cancer MCF-7 cells, respectively. Analysis of the N-linked glycan structure ofMAL confirmed the presence of eight glycans, comprising two α1,3-fucosylated paucimannosidic-type and six high-mannose-type glycans. Glycan analysis of MAL that had been treated with peptide N-glycosidase F (de-M-MAL) revealed that while the two α1,3-fucosylated paucimannosidic glycans remained attached following the treatment, the six high-mannose-type glycans had been completely cleaved from the original MAL. There were almost no secondary structural changes between MAL and de-M-MAL; however, the lectin activities exhibited by MAL, such as hemagglutination and binding to a sialoglycoprotein, were completely absent in de-M-MAL, and the ability to detect human breast cancer MCF-7 cells was 77% lower in de-M-MAL than in MAL. The high-mannose-type glycans in intact MAL are closely associated with its lectin activities. This is the first report of the N-linked glycan structure of MAL and the effect of high mannose-type glycans on lectin activities.
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Effects of selective cleavage of high-mannose-type glycans of Maackia amurensis Leukoagglutinin on sialic acid-binding activity
Biochimica et biophysica acta, 2015Co-Authors: Byung Sun Kim, Hye Seong Hwang, Heajin Park, Ha Hyung KimAbstract:Abstract Background Maackia amurensis Leukoagglutinin (MAL) is a glycoprotein and sialic acid-binding lectin that is used widely in the detection and characterization of sialoglycoconjugates and human cancer cells. However, its N-linked glycan structure and role have yet to be determined. Methods The N-linked glycans were analyzed using high-performance liquid chromatography with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and the secondary structure was investigated using circular dichroism analysis. A hemagglutination assay was performed. Furthermore, surface plasmon resonance analysis, and fluorescence microscopy and fluorescence-activated cell-sorting analysis were conducted to assess the sialoglycoprotein-binding ability and its usefulness in the detection of human breast cancer MCF-7 cells, respectively. Results Analysis of the N-linked glycan structure of MAL confirmed the presence of eight glycans, comprising two α1,3-fucosylated paucimannosidic-type and six high-mannose-type glycans. Glycan analysis of MAL that had been treated with peptide N-glycosidase F (de-M-MAL) revealed that while the two α1,3-fucosylated paucimannosidic glycans remained attached following the treatment, the six high-mannose-type glycans had been completely cleaved from the original MAL. There were almost no secondary structural changes between MAL and de-M-MAL; however, the lectin activities exhibited by MAL, such as hemagglutination and binding to a sialoglycoprotein, were completely absent in de-M-MAL, and the ability to detect human breast cancer MCF-7 cells was 77% lower in de-M-MAL than in MAL. Conclusion The high-mannose-type glycans in intact MAL are closely associated with its lectin activities. General significance This is the first report of the N-linked glycan structure of MAL and the effect of high-mannose-type glycans on lectin activities.
Pgm Luiten - One of the best experts on this subject based on the ideXlab platform.
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patterns of direct projections from the hippocampus to the medial septum diagonal band complex anterograde tracing with phaseolus vulgaris leucoagglutinin combined with immunohistochemistry of choline acetyltransferase
Neuroscience, 1991Co-Authors: R. P. A. Gaykema, J. Van Der Kuil, Louis B Hersh, Pgm LuitenAbstract:The projections from the Ammon's horn to the cholinergic cell groups in the medial septal and diagonal band nuclei were investigated with anterograde tracing of Phaseolus vulgaris leucoagglutinin combined with immunocytochemical detection of choline acetyltransferase, in the rat. Tracer injections were placed into various fields of the septal and temporal parts of the Ammon's horn (CA1-3). These injections revealed differential distributions of Phaseolus vulgaris leucoagglutinin-labeled projections in both the lateral septal area and the medial septum-diagonal band complex. In addition to the labeling of dense axonal networks in the lateral septal area, significant numbers of arborizing fibers were labeled in the medial septal and diagonal band nuclei, in particular after tracer injections into the fields CA2-3. The distributions of the projections to the medial septum-diagonal band complex arising from the septal portion of fields CA1 and CA2-3 are similar. In contrast, the septal part and temporal portion of field CA3 project in a topographically differentiated manner to the medial septum and nuclei of the diagonal band. The septal pole of the Ammon's horn innervates the dorsal and medial parts of the medial septal nucleus and the anterior and dorsal parts of the vertical limb of the diagonal band. Axons of the temporal pole of the hippocampus reach the lateral and ventral parts of the medial septum and the intermediate, caudal and ventral parts of the vertical limb of the diagonal band. These results demonstrate direct feedback projections of the Ammon's horn to the medial septum-diagonal band complex, which show a topographic organization mainly as a function of the septotemporal level of the hippocampus. Within the medial septal and diagonal band nuclei, the labeled varicosities are formed in close proximity to the cell bodies and dendrites of the cholinergic neurons.
Gnanesh Kumar B.s - One of the best experts on this subject based on the ideXlab platform.
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Comprehensive analysis of α 2-3-linked sialic acid specific Maackia amurensis leukagglutinin reveals differentially occupied N-glycans and C-terminal processing.
International journal of biological macromolecules, 2016Co-Authors: Gnanesh Kumar B.s, Avadhesha SuroliaAbstract:Seeds of Maackia amurensis constitutes two sialic acid specific agglutinins known as leukagglutinin and hemagglutinin. Maackia amurensis leukagglutinin (MAL) recognizes alpha 12-3-linked sialic acid present mainly in N-glycans and composed of two disulfide linked monomers. It exhibits potential N-glycosylation sites (four PNGs) which have been assumed to undergo differential occupancy. In this study we have characterized the site specific macro- and microheterogeneity of monomers in detail by analysing N-glycopeptides and peptides through liquid chromatography coupled to ion trap mass spectrometer in MS3 mode (LC-MSn). We observed the presence of mainly paucimannose N-glycans at Asn(61), Asn(113) and Asn(191) whereas a high mannose type with varying Man(5-9) occurs at Asn(179). Interestingly Asn(179) and Asn(191) exhibited differential occupancy which was evident by the presence of non-glycosylated peptides. This has contributed to the difference in molecular mass of monomers upon SDS-PAGE. Further the presence of disulfide linked peptides confirmed the covalent linkage of monomers which also undergoes uniform C-terminal processing. (C) 2016 Elsevier B.V. All rights reserved.