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Examines the therapeutic agent with oriented carbohydrates in treating infections caused by Shiga toxin-producing (Stx) Escherichia coli. Development of carbosilane dendrimers; Effects of Stx; Degradation of Stx by phagocytic macrophages in reticuloendothelial system.

Graphical abstract Highlights • Sugar-amino acid hybrid monomers were prepared. • Assembly of the monomers was accomplished by radical polymerization. • Affinities of the polymers against Stxs were examined. • High cluster-type polymers showed higher affinity than low cluster-type polymers. Abstract Synthetic assembly of sugar moieties and amino acids in order to create "sugar-amino acid hybrid polymers" was accomplished by means of simple radical polymerization of carbohydrate monomers having an amino acid-modified polymerizable aglycon. Amines derived from globotriaoside and lactoside as glycoepitopes were condensed with known carbobenzyloxy derivatives, including Z-Gly, Z- l -Ala and Z-β-Ala, which had appropriate spacer ability and a chiral center to afford fully protected sugar-amino acid hybrid compounds in good yields. After deprotection followed by acryloylation, the water-soluble glycomonomers were polymerized with or without acrylamide in the presence of a radical initiator in water to give corresponding copolymers and homopolymers, which were shown by SEC analysis to have high molecular weights. Evaluation of the biological activities of the glycopolymers against Shiga toxins (Stxs) was carried out, and the results suggested that glycopolymers having highly clustered globotriaosyl residues had high affinity against Stx2 (K D = 2.7∼4.0 µM) even though other glycopolymers did not show any affinity or showed very weak binding affinity. When Stx1 was used for the same assay, all of the glycopolymers having globotriaosyl residues showed high affinity (K D = 0.30∼1.74 µM). Interestingly, couple of glycopolymers having lactosyl moieties had weaker binding affinity against Stx1. In addition, when cytotoxicity assays were carried out for both Stxs, glycopolymers having highly clustered globotriaosyl residues showed higher affinity than that of the copolymers, and only highly clustered-type glycopolymers displayed neutralization potency against Stx2. [ABSTRACT FROM AUTHOR]

Review: 54 refs. [ABSTRACT FROM AUTHOR]

Abstract: Synthetic construction of fucosyl chitobiose [GlcNAcβ1→4(Fucα1→3)GlcNAc] as an allergy-associated carbohydrate epitope was accomplished from three building blocks. The trisaccharidic unit was further transformed into a carbohydrate monomer and polymerization of the glycomonomer proceeded smoothly to provide a series of glycopolymers having various carbohydrate densities. In addition to the organic syntheses, biological evaluations of the glycomonomer and the polymers were carried out and sugar-clustering effects were observed. [Copyright &y& Elsevier]

Convenient and useful construction of a trisaccharide moiety of globotriaosyl ceramide was performed by means of modified Ogawa’s protocol. In order to evaluate an efficiency of new class of glycopolymers, further chemical transformations of the trisaccharide were accomplished to afford a globotriaosyl carbohydrate monomer, and homopolymerization of the monomer by a general radical polymerization protocol gave a high-density glycopolymer in 84.3% yield after usual work-up procedures. In addition to the homopolymer, a copolymer composed of carbohydrate units and acrylamide units was also synthesized by the radical polymerization in 96.7% yield. [Copyright &y& Elsevier]

As an artificial ligand, a glycoconjugate polymer carrying carbohydrate moiety of lactosyl ceramide or globotriaosyl ceramide (Gb3) was synthesized. Gb3 is known as the receptor of Shiga toxin-producing Escherichia coli O157: H7. The preparation of the glycoconjugate polymer initially involves the construction of the carbohydrate moiety of Gb3 derivative which has n-pentenyl group as polymerizable group. In addition, the n-pentenyl group of the Gb3 derivative was modified and different polymerizable groups such as acrylamide group were introduced at ω-position of the aglycon. Radical polymerization of the synthesized glycosyl monomers with or without acrylamide proceeded smoothly in water using ammonium persulfate and N, N, N′, N′-tetramethylethylenediamine as usual initiator system and gave water-soluble glycoconjugate polymers having various polymer compositions. These polymers have the potential to neutralize Shiga toxin by reason of cluster effect and multivalency. [Copyright &y& Elsevier]