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Galectin-8 Downmodulates TLR4 Activation and Impairs Bacterial Clearance in a Mouse Model of Pseudomonas aeruginosa Keratitis

Pseudomonas aeruginosa provokes a painful, sight-threatening corneal infection. It progresses rapidly and is difficult to treat. In this study, using a mouse model of P. aeruginosa keratitis, we demonstrate the importance of a carbohydrate-binding protein, galectin-8 (Gal-8), in regulation of the innate immune response. First, using two distinct strains of P. aeruginosa, we established that Gal-8−

The role of Galectin-3 in α-synuclein-induced microglial activation

Background: Parkinson's disease (PD) is the most prevalent neurodegenerative motor disorder. The neuropathology is characterized by intraneuronal protein aggregates of α-synuclein and progressive degeneration of dopaminergic neurons within the substantia nigra. Previous studies have shown that extracellular α-synuclein aggregates can activate microglial cells, induce inflammation and contribute to

Ligand binding and complex formation of galectin-3 is modulated by pH variations

Galectin-3-dependent clusters or lattices are formed at the surface as well as in distinct organelles of eukaryotic cells. Incorporation into membrane proximal networks can fix glycoproteins within subcellular domains or sort them into distinct transport pathways. In the present paper we analysed the effect of acidification on the sugar binding and self-oligomerization of galectin-3. Using a fluor

Bacterial adhesion of Streptococcus suis to host cells and its inhibition by carbohydrate ligands

Streptococcus suis is a Gram-positive bacterium, which causes sepsis and meningitis in pigs and humans. This review examines the role of known S. suis virulence factors in adhesion and S. suis carbohydrate-based adhesion mechanisms, as well as the inhibition of S. suis adhesion by anti-adhesion compounds in in vitro assays. Carbohydrate-binding specificities of S. suis have been identified, and th

A study of the donor properties of sialyl phosphites having an auxiliary 3-(S)-phenylseleno group

Two phosphite sialyl donors, each having an auxiliary 3-(S)-phenylseleno group, were prepared and evaluated. The phenylseleno group was introduced via a new mode of generating phenylselenenic acid (‘PhSeOH’). Although the sialyl donors provided fair yields (32–76%) of the desired sialosides in glycosylations of the reactive acceptor 1,2;3,4-di-O-isopropylidene-α-d-galactopyranose, no sialylated pr

An efficient and convergent route towards water-soluble, chiral and amphiphilic macrocycles

A practical procedure for the synthesis of water-soluble, chiral and amphiphilic macrocyclic molecules is described. Acylation of p-xylylene diamine with Fmoc-protected glycine and aspartic acid, followed by removal of the Fmoc moiety afforded amino acid:p-xylene conjugates as free diamines. These diamines were converted to symmetrical and unsymmetrical macrocycles via stepwise urea formation u

The p-methoxybenzyl ether as an in situ-removable carbohydrate-protecting group : A simple one-pot synthesis of the globotetraose tetrasaccharide

A one-pot synthesis of the globotetraose tetrasaccharide is reported. The synthetic method relies on the use of a p-methoxybenzyl ether as an in situ-removable protecting group. N-Iodosuccinimide/trifluoromethanesulfonic acid-promoted glycosylation of 2-bromoethyl-2,3,6-tri-O-benzoyl-4-O-(2,3,6-tri-O-benzoyl-β-D-galactopyranosyl)-β-D-glucopyranoside 5 at −45 °C with phenyl 2,4,6-tri-O-benzyl-3-O-(

Solid-phase extraction for combinatorial libraries

Solid-phase extraction (SPE) has during the last three years emerged as a convenient method for the purification of compound libraries prepared by solution synthesis. The widespread use of SPE in combinatorial chemistry can be explained by straightforward SPE method development facilitated by the availability of numerous commercial SPE resins. High-speed automated SPE is readily accomplished by ta

Conversion of 2-(trimethylsilyl)ethyl sulfides into thioesters

Treatment of 2-(trimethylsilyl)ethyl sulfides with a carboxylic acid chloride and AgBF4 in CH2Cl2 furnishes the corresponding thioesters in high yields and purities. The conversion of 2-(trimethylsilyl)ethyl sulfides into synthetically versatile thioesters allows such sulfides to be used as sulfhydryl protective groups, since such sulfides are easily prepared and are stable towards many reaction c

Parallel solution synthesis of a 'carbohybrid' library designed to inhibit galactose-binding proteins

Parallel solution S-alkylations of a 1-thio-β-D-galactopyranoside derivative with Michael acceptors and α-chloroketones, followed by ketone reductions, reductive aminations, and acylations were developed to yield a library of 1-thio-β-D-galactopyranosides carrying small and diverse polar- neutral, hydrophobic, aromatic, cationic, or anionic non-carbohydrate aglycon structures. Screening of the lib

Comparative 1H NMR study of hydroxy protons in galabioside and its S-linked 4-thiodisaccharide analogue in aqueous solution

The NMR data obtained from hydroxy protons have been used to investigate the presence and absence of intramolecular hydrogen bonding in aqueous solutions of 2-(trimethylsilyl)ethyl galabioside (α-D-Galp-(1→4)-β-D-Galp-O(CH2)2SiMe3) and the S-linked 4-thiodisaccharide analogue. The data show that there is a weak hydrogen bond interaction between O-6H and O-2'H in galabioside, but not in the thio-an

Solid-phase extraction on C18 silica as a purification strategy in the solution synthesis of a 1-Thio-β-D-galactopyranoside library

A novel strategy for the purification of carbohydrate-based chemical libraries synthesized in solution was developed. Purification of reaction products was accomplished by means of solid-phase extraction enabled by protecting the 2-, 3-, 4-, and 6-hydroxyl groups of a galactose derivative as their hydrophobic O-laurates. The presence of multiple O-laurates allowed adsorption of reaction products o

Immobilization of reducing sugars as toxin binding agents

A simple and economical procedure for the attachment of reducing sugars to aminated solid supports has been developed. Reaction of the amino groups on the solid support with p-nitrophenyl chloroformate, followed by 1,6-hexanediamine, yields a chain-extended amine to which reducing sugars can be attached while remaining accessible to macromolecules. Immobilization of the reducing sugars involves a

PapG adhesin from E. coli J96 recognizes the same saccharide epitope when present on whole bacteria and as isolated protein

Purified PapG adhesin from the genetically well-defined uropathogenic Escherichia coli strain J96, as well as whole bacteria, were bound to microtiter plates that carried covalently bound globotetraose and galabiose. The binding was inhibited by soluble saccharide derivatives corresponding to the globoseries of glycolipids, including all di-, tri-, tetra-, and pentasaccharide fragments of the Fors

Determination of the degree of branching in normal and amylopectin type potato starch with 1H-NMR spectroscopy : Improved resolution and two-dimensional spectroscopy

Starch from genetically modified potatoes was found to be highly branched compared with normal potato varieties through the use of 1H-NMR spectroscopy. The average chain length, blue-value,and the wavelength at maximum absorptivity clearly show that the new potato varieties produce amylopectin starch. Correlation between the degree of branching as determined by 1H-NMR and starch-iodine complexatio

Synthesis, conformational analysis and comparative protein binding of a galabioside and its thioglycoside analogues

The two thio analogues (2 and 3) of TMSEt galabioside [2-(trimethylsilyl) ethyl 4-O-(α-D-galactopyranosyl)-β-D-galactopyranoside, 1], having anomeric sulfur instead of anomeric oxygen atoms, were synthesized and their conformations investigated by NMR and computational (MM3) methods. A spacer galabioside was covalently coupled to aminated microtiter plates, and binding of a bacterial pilus adhesin

Major histocompatibility complex class I binding glycopeptides for the estimation of 'empty' class I molecules

Different forms of major histocompatibility complex (MHC) class I heavy chains are known to be expressed on the cell surface, including molecules which are functionally 'empty'. Direct peptide binding to cells is obvious during sensitization of target cells in vitro for cytotoxic T lymphocyte killing and 'empty' MHC-I molecules are comparatively abundant on TAP- 1 2 peptide transporter mutant cell

Body weight at age 20 and in midlife is more important than weight gain for coronary atherosclerosis : results from SCAPIS

Background and aimsElevated body weight in adolescence is associated with early cardiovascular disease, but whether this association is traceable to weight in early adulthood, weight in midlife or to weight gain is not known. The aim of this study is to assess the risk of midlife coronary atherosclerosis being associated with body weight at age 20, body weight in midlife and body weight change.Met