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Several hydrophobic glycosides of N-acetylglucosamine (GlcNAc) served as primers for polylactosamine synthesis when added to Chinese hamster ovary (CHO) cells. The modified glycosides, containing one to six lactosamine repeats in linear array, were sialylated and secreted into the culture medium. The relative efficiencies of the glycosides to serve as primers were dependent on the nature of the aglycone and on the anomeric configuration of the GlcNAc residue. The same compounds were tested for their effects on glycolipid synthesis in CHO cells. All of the beta-glycosides significantly inhibited the synthesis of the lactoseries glycolipid GM3 whereas the alpha-glycoside was inactive. The compound GlcNAc alpha 1-O-benzyl- was the most efficient primer of polylactosamine synthesis and had no effect on glycolipid synthesis. This compound may have potential for the assay of the polylactosamine synthetic capacity of living cells

Methyl 2-O-α-D-galactopyranosyl-α-D-mannopyranoside coffee bean α-galactosidase sensitivity of a synthetic fragment of a Trypanosoma brucei GPI anchor

The synthesis of methyl 2-O-α-D-galactopyranosyl-α-D-mannopyranoside, a fragment of a Trypanosoma brucei Variant Surface Glycoprotein GPI anchor structure, and its susceptibility to hydrolysis by coffee bean α-galactosidase are reported

Acceptor analogues as potential inhibitors of bovine β-1,4-galactosyl transferase

A series of 4- and 6-substituted derivatives of benzyl N-acetyl-β-D-glucosaminide were prepared and assessed as inhibitors of bovine β-1,4-galactosyl transferase. Of the azido, amino, and acetamido compounds tested, only the 4-amino compound (2) produced significant inhibition of this enzyme

GPI-anchored proteins and free GPI glycolipids of procyclic form Trypanosoma brucei are nonessential for growth, are required for colonization of the Tsetse fly, and are not the only components of the surface coat

The procyclic form of Trypanosoma brucei exists in the midgut of the tsetse fly. The current model of its surface glycocalyx is an array of rod-like procyclin glycoproteins with glycosylphosphatidylinositol (GPI) anchors carrying sialylated poly-N-acetyllactosamine side chains interspersed with smaller sialylated poly-N-acetyllactosamine–containing free GPI glycolipids. Mutants for TbGPI12, deficient in the second step of GPI biosynthesis, were devoid of cell surface procyclins and poly-N-acetyllactosamine–containing free GPI glycolipids. This major disruption to their surface architecture severely impaired their ability to colonize tsetse fly midguts but, surprisingly, had no effect on their morphology and growth characteristics in vitro. Transmission electron microscopy showed that the mutants retained a cell surface glycocalyx. This structure, and the viability of the mutants in vitro, prompted us to look for non-GPI–anchored parasite molecules and/or the adsorption of serum components. Neither were apparent from cell surface biotinylation experiments but [3H]glucosamine biosynthetic labeling revealed a group of previously unidentified high apparent molecular weight glycoconjugates that might contribute to the surface coat. While characterizing GlcNAc-PI that accumulates in the TbGPI12 mutant, we observed inositolphosphoceramides for the first time in this organism