One-pot synthesized neoglycoconjugates with a reactive thiol group are introduced here for functionalization with carbohydrates for solubilization and stabilization of CdSe-ZnS quantum dots in aqueous solution. Three different sizes of quantum dots (QDs) with lactose, melibiose, and maltotriose on their surface have been utilized, for the first time, for lectin detection through agglutination assay. The sugar-QDs thus synthesized were characterized by transmission election microscopy (TEM), fluorescence, and absorption spectroscopy. Agglutination of sugar-QDs by three different lectins occurred through specific multivalent carbohydrate-lectin interactions and was studied extensively by monitoring the scattered light at 600 nm. This assay was very selective, which has been demonstrated by a more selective binding of soybean agglutinin (SBA) with melibiose-QD, as compared to lactose-QD, and specific deagglutination caused by alpha-d-galactose, while alpha-d-mannose did not show any effect. The detection sensitivity of the maltotriose-QD was tested with Concanavalin A (ConA), and as little as 100 nM of the lectin was detected using light scattering. The detection sensitivity of this protocol has been enhanced considerably by the fluorescence properties of QDs. This agglutination process seems to occur through formation of smaller soluble aggregates, which further associate to form larger aggregates.

Neutrophils are the most abundant white blood cells in humans and play a vital role in several aspects of the immune response. Numerous reports have implicated neutrophil glycosylation as an important factor in mediating these interactions. We report here the application of high sensitivity glycomics methodologies, including matrix assisted laser desorption ionisation (MALDI-TOF) and MALDI-TOF/TOF analyses, to the structural analysis of N-and O-linked carbohydrates released from two samples of neutrophils, prepared by two separate and geographically remote laboratories. The data produced demonstrates that the cells display a diverse range of sialylated and fucosylated complex glycans, with a high level of similarity between the two preparations.

The genus Corynebacterium is part of the phylogenetic group nocardioform actinomycetes, which also includes the genus Mycobacterium. Members of this phylogenetic group have a characteristic cell envelope structure, which is dominated by complex lipids and amongst these, lipoglycans are of particular interest. The disruption of NCgl2106 in C. glutamicum resulted in a mutant devoid of monoacylated phosphatidyl-myo-inositol dimannoside (Ac 1 PIM 2 ) resulting in the accumulation of Ac 1 PIM 1 and cessation of phosphatidyl-myo-inositol (PI) based lipomannan (Cg-LM, now also termed 'Cg-LM-A') and lipoarabinomannan (Cg-LAM) biosynthesis. Interestingly, SDS-analysis of the lipoglycan fraction from the mutant revealed the synthesis of a single novel lipoglycan, now termed 'Cg-LM-B'. Further chemical analyses established the lipoglycan possessed an a-D-glucopyranosyluronic acid-(1 ? 3)-glycerol (GlcAGroAc 2 ) based anchor which was then further glycosylated by 8-22 mannose residues, with Man 12-20 GlcAGroAC 2 molecular species being the most abundant, to form a novel lipomannan structure (Cg-LM-B). The deletion of NCgl2106 in C. glutamicum has now provided a useful strain, in addition with a deletion mutant of NCgl0452 in C. glutamicum for the purification of Cg-LM-A and Cg-LM-B. Interestingly, both Cg-LM species induced a similar production of TNF-a by a human macrophage cell line suggesting that the phospho-myo-inositol residue of the PI-anchor does not play a key role in lipoglycan pro-inflammatory activity.

Some bacterial flagellins are O-glycosylated on surface-exposed Serine/Threonine residues with nonulosonic acids such as pseudaminic acid, legionaminic acid, and their derivatives by flagellin nonulosonic acid glycosyltransferases, also called Motility associated factors (Maf). We report here two new glycosidic linkages previously unknown in any organism, Serine/Threonine-O-linked N-Acetylneuraminic acid (Ser/Thr-O-Neu5Ac) and Serine/Threonine-O-linked 3-Deoxy-D-manno-octulosonic acid (Ser/Thr-O-KDO), both catalysed by Geobacillus kaustophilus Maf and Clostridium botulinum Maf. We identified these novel glycosidic linkages in recombinant G. kaustophilus and C. botulinum flagellins that were co-expressed with their cognate recombinant Maf protein in Escherichia coli strains producing the appropriate nucleotide sugar glycosyl donor. Our finding, that both G. kaustophilus Maf (putative flagellin sialyltransferase) and C. botulinum Maf (putative flagellin legionaminic acid transferase) catalyzed Neu5Ac and KDO transfer on to flagellin, indicates that Maf glycosyltransferases display donor substrate promiscuity. Maf glycosyltransferases have the potential to radically expand the scope of neoglycopeptide synthesis and posttranslational protein engineering.

Cell-cell communications, cell-matrix interactions, and cell migrations play a major role in regeneration. However, little is known about the molecular players involved in these critical events, especially cell surface molecules. Here, we demonstrate the role of specific glycan-receptor interactions in the regenerative process using Hydra magnipapillata as a model system. Global characterization of the N- and O-glycans expressed by H. magnipapillata using ultrasensitive mass spectrometry revealed mainly polyfucosylated LacdiNAc antennary structures. Affinity purification showed that a putative C-type lectin (accession number Q6SIX6) is a likely endogenous receptor for the novel polyfucosylated glycans. Disruption of glycan-receptor interactions led to complete shutdown of the regeneration machinery in live Hydra. A time-dependent, lack-of-regeneration phenotype observed upon incubation with exogenous fuco-lectins suggests the involvement of a polyfucose receptor-mediated signaling mechanism during regeneration. Thus, for the first time, the results presented here provide direct evidence for the role of polyfucosylated glycan-receptor interactions in the regeneration of H. magnipapillata.