Background: Salmonella enterica serotype Typhimurium is a nontyphoidal and common foodborne pathogen that causes serious threat to humans. There is no licensed vaccine to prevent the nontyphoid bacterial infection caused by S. Typhimurium.
View Article and Find Full Text PDFFor a detailed examination of the interaction of rhamnose containing derivatives with recombinant horseshoe crab plasma lectin (rHPL), two di-rhamno-di-lipids (an α-1,2- and an α-1,3-linked) were synthesized via a new simple method. The N-iodosuccinimide/triflic acid mediated glycosylation of the methyl (R)-3-hydroxydecanoate with phenyl-1-thio-rhamnobioside donors afforded the mono-lipid disaccharides. Removal of the methyl ester group followed by esterification of the mono-lipids with a second (R)-3-hydroxydecanoate unit resulted in fully protected di-lipid derivatives, transformation of which into the target compounds was accomplished in two steps.
View Article and Find Full Text PDFThis study demonstrates the utilization of a flow chemistry system for continuous glycan hydrolysis and saccharide labeling to assist with the existing methods in glycan structural analysis. Acidic hydrolysis of glycans could be accelerated in a flow system. Aldoses and α-ketoacid-type saccharides were effectively labeled with naphthalene-2,3-diamine (NADA) at 60 °C for 10 min to form the fluorescent naphthimidazole (NAIM) and quinoxalinone (QXO) derivatives, respectively.
View Article and Find Full Text PDFMore than 80% of infectious bacteria form biofilm, which is a bacterial cell community surrounded by secreted polysaccharides, proteins and glycolipids. Such bacterial superstructure increases resistance to antimicrobials and host defenses. Thus, to control these biofilm-forming pathogenic bacteria requires antimicrobial agents with novel mechanisms or properties.
View Article and Find Full Text PDFThe glycan part of glycoproteins is known to be involved in the structure and modulatory functions of glycoproteins, serving as ligands for cell-to-cell interactions, and as specific ligands for cell-to-microbe interactions. It is believed that intraspecies and interspecies variations in glycosylation exist. As an approach to better understand glycan diversity, egg whites (EW) from four different quail species are studied by the well-established glycoblotting procedure, a glycan enrichment and analysis method.
View Article and Find Full Text PDFTo evaluate the molecular interaction of recombinant horseshoe crab plasma lectin (rHPL) with Pseudomonas aeruginosa PAO1, multivalent rhamnobioside derivatives were designed. Eight rhamnoclusters with three or four α(1-3)-rhamnobiosides attached to different central cores, such as methyl gallate, pentaerythritol, and N-Boc Tris, through either an ethylene glycol or a tetraethylene glycol linker, were assembled in two consecutive azide-alkyne cycloaddition click reactions. The synthetic method embraced the preparation of two α(1-3)-rhamnobiosides with different linker arms and their conjugation, in stoichiometric or substoichiometric amounts, to propargyl ether-functionalized tri- or tetravalent scaffolds.
View Article and Find Full Text PDFHorseshoe crab is an ancient marine arthropod that, in the absence of a vertebrate-like immune system, relies solely on innate immune responses by defense molecules found in hemolymph plasma and granular hemocytes for host defense. A plasma lectin isolated from the hemolymph of Taiwanese Tachypleus tridentatus recognizes bacteria and lipopolysaccharides (LPSs), yet its structure and mechanism of action remain unclear, largely because of limited availability of horseshoe crabs and the lack of a heterogeneous expression system. In this study, we have successfully expressed and purified a soluble and functional recombinant horseshoe crab plasma lectin (rHPL) in an Escherichia coli system.
View Article and Find Full Text PDFHuman eosinophil cationic protein (ECP) and eosinophil derived neurotoxin (EDN) are two ribonuclease A (RNaseA) family members secreted by activated eosinophils. They share conserved catalytic triad and similar three dimensional structures. ECP and EDN are heparin binding proteins with diverse biological functions.
View Article and Find Full Text PDFUnlabelled: Signaling of the receptor for advanced glycation end products (RAGE) has been implicated in the development of injury-elicited vascular complications. Soluble RAGE (sRAGE) acts as a decoy of RAGE and has been used to treat pathological vascular conditions in animal models. However, previous studies used a high dose of sRAGE produced in insect Sf9 cells (sRAGE(Sf9))and multiple injections to achieve the therapeutic outcome.
View Article and Find Full Text PDFHuman eosinophil derived neurotoxin (EDN), a granule protein secreted by activated eosinophils, is a biomarker for asthma in children. EDN belongs to the human RNase A superfamily possessing both ribonucleolytic and antiviral activities. EDN interacts with heparin oligosaccharides and heparin sulfate proteoglycans on bronchial epithelial Beas-2B cells.
View Article and Find Full Text PDFThe N-terminal starch binding domain of Rhizopus oryzae glucoamylase (RoSBD) has a high binding affinity for raw starch. RoSBD has two ligand-binding sites, each containing a ligand-binding clamp: a polyN clamp residing near binding site I is unique in that it is expressed in only three members of carbohydrate binding module family 21 (CBM21) members, and a Y32/F58 clamp located at binding site II is conserved in several CBMs. Here we characterized different roles of these sites in the binding of insoluble and soluble starches using an amylose-iodine complex assay, atomic force microscopy, isothermal titration calorimetry, site-directed mutagenesis, and structural bioinformatics.
View Article and Find Full Text PDFAdv Exp Med Biol
October 2011
A large set of glycome information was obtained from egg white proteins of 88 samples from Galloanserae (63 Anseriformes and 25 Galliformes). The data were obtained on whole N-glycan structures and types of sialic acids of these egg whites by glycoblotting-based high-throughput and quantitative glycomics. The results revealed clear trends and complexity patterns as well as diversity among taxonomic groups.
View Article and Find Full Text PDFMALDI-MS provides a rapid and sensitive analysis of large biomolecules such as proteins and nucleic acids. However, oligo- and polysaccharides are less sensitive in MS analysis partly due to their neutral and hydrophilic nature to cause low ionization efficiency. In this study, four types of oligosaccharides including aldoses, aminoaldoses, alduronic acids and α-keto acids were modified by appropriate tags at the reducing termini to improve their ionization efficiency.
View Article and Find Full Text PDFTo understand the roles of species-specific carbohydrates, systematic studies of interspecific glycan analyses are imperative. An extensive series of glycomics studies on approximately 180 kinds of bird eggs have demonstrated that 60-70% of the birds, which are closely related in phylogeny, express the alpha-Galp-(1-->4)-Galp structure on their egg glycoproteins. This prompted us to investigate the glycosylation profiles of eggs from an evolutionarily related organism, a sea turtle (reptilian).
View Article and Find Full Text PDFSo far, there have been only a few matrices reported for detection of polysaccharides with molecular weight higher than 3000 Daltons by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). In this work, we found that 2',4',6'-trihydroxyacetophenone (THAP) is a good matrix for MALDI time-of-flight MS analysis of polysaccharides with broad mass range. Large polysaccharides, dextrans, glycoproteins and polysialic acids have been successfully detected by MALDI-MS with THAP as matrix.
View Article and Find Full Text PDFPurpose: Multidrug resistance (MDR) continues to be a major obstacle for successful anticancer therapy. One of the principal factors implicated in MDR is the over expression of P-glycoprotein (Pgp), the product of the MDR1 gene.
Methods: Here we explore the possibility of using the transcription inhibitor tetra-O-methyl nordihydroguaiaretic acid (M4N) to inhibit Sp1-regulated MDR1 gene expression and restore doxorubicin and paclitaxel sensitivity to multidrug resistant human cancer cells in vitro and in vivo.
An affinity labeling reagent, uridine 5'-(6-amino-{2-[(7-bromomethyl-2-naphthyl)methoxycarbonylmethoxy]ethoxy}acetyl-6-deoxy-alpha-D-galactopyranosyl) diphosphate (1a), was designed on the basis of 3D docking simulation and synthesized to investigate the functional role of Trp310 residue located in the small loop near the active site of human recombinant galactosyltransferase (betaGalT-1). Mass spectrometric analysis revealed that the Trp310 residue of betaGalT1 can be selectively modified with the naphthylmethyl group of compound 1a at the C-3 position of the indole ring. This result motivated us to synthesize novel uridine-5'-diphosphogalactose (UDP-Gal) analogues as candidates for mechanism-based inhibitors for betaGalT-1.
View Article and Find Full Text PDF(4-N-5-Dimethylaminonaphthalene-1-sulfonyl-2-difluoromethylphenyl)-beta-d-galactopyranoside was synthesized and successfully tested on beta-galactosidases from Xanthomonas manihotis (Wong-Madden, S. T., and Landry, D.
View Article and Find Full Text PDFTo evaluate the ability of insect cells to produce complex-type N-glycans, beta-(1 --> 4)-galactosyltransferase (beta4GalT) activity in several insect cell lines was analyzed. For this purpose, we developed a simple and highly sensitive assay for beta-(1 --> 4)-galactosyltransferase (beta4GalT) activity, which is based on time-resolved fluorometry of europium. Bovine serum albumin (BSA) modified with GlcNAc (GlcNAc(44)-BSA) was used as the acceptor.
View Article and Find Full Text PDF