Synthetic mucin fragments. Benzyl O-beta-D-galactopyranosyl-(1----3)-O-(2-acetamido-2-deoxy-beta-D- glucopyranosyl)-(1----6)-2-acetamido-2-deoxy-alpha-D-galactopyranoside and O-alpha-L-fucopyranosyl-(1----3)-O-(2-acetamido-2-deoxy-beta-D- glucopyranosyl)-(1----6)-2-acetamido-2-deoxy-D-galactopyranose

Phenotypic diversity and metabolic specialization of renal endothelial cells

Complex multicellular life in mammals relies on functional cooperation of different organs for the survival of the whole organism. The kidneys play a critical part in this process through the maintenance of fluid volume and composition homeostasis, which enables other organs to fulfil their tasks. The renal endothelium exhibits phenotypic and molecular traits that distinguish it from endothelia of other organs. Moreover, the adult kidney vasculature comprises diverse populations of mostly quiescent, but not metabolically inactive, endothelial cells (ECs) that reside within the kidney glomeruli, cortex and medulla. Each of these populations supports specific functions, for example, in the filtration of blood plasma, the reabsorption and secretion of water and solutes, and the concentration of urine. Transcriptional profiling of these diverse EC populations suggests they have adapted to local microenvironmental conditions (hypoxia, shear stress, hyperosmolarity), enabling them to support kidney functions. Exposure of ECs to microenvironment-derived angiogenic factors affects their metabolism, and sustains kidney development and homeostasis, whereas EC-derived angiocrine factors preserve distinct microenvironment niches. In the context of kidney disease, renal ECs show alteration in their metabolism and phenotype in response to pathological changes in the local microenvironment, further promoting kidney dysfunction. Understanding the diversity and specialization of kidney ECs could provide new avenues for the treatment of kidney diseases and kidney regeneration.

Synthetic antigens as immunogens: Part IV. Specificity of antisera developed to Gal beta 1-3(GlcNAc beta 1-6)GalNAc and GlcNAc beta 1-6GalNAc

Antisera to the chemically synthesized trisaccharide, Gal beta 1-3(GlcNAc beta 1-6)GalNAc, and disaccharide, GlcNAc beta 1-6GalNAc, were developed using the diazophenyl bovine serum albumin derivatives. The binding specificity of the antisera were analyzed by enzyme immunoassays with structurally related, chemically synthesized oligosaccharides. The anti-trisaccharide antibody showed no reactivity to T antigenic structures which bear the Gal beta 1-3GalNAc moiety. The immunodominant area of the Gal beta 1-3(GlcNAc beta 1-6)GalNAc was contained in the GlcNAc beta 1-6GalNAc region of the molecule. The reactivity pattern of the anti-trisaccharide antibody, although directed to the disaccharide, did not exactly duplicate the reactivity pattern of the anti-disaccharide.

Synthesis of some oligosaccharides containing the O-(2-acetamido-2-deoxy- beta-D-glucopyranosyl)-(1----2)-O-alpha-D-mannopyranosyl unit. Potential substrates for UDP-GlcNAc:alpha-D-mannopyranosyl-(1----6)-N-acetyl-beta-D- glucosaminyltransferase (GnT-V)

Four different oligosaccharides containing the 2-acetamido-2-deoxy-beta-D-glucopyranosyl-(1----2)-alpha-D-mannopyran osy l sequence as a terminal disaccharide unit were synthesized, namely: 4-nitrophenyl O-(2-acetamido-2-deoxy-beta-D- glucopyranosyl)-(1----2)-O-alpha-D-mannopyranosyl-(1----6)-beta-D- mannopyranoside (27), 4-nitrophenyl O-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-(1----2)-O-alpha-D-mann opy ranosyl - (1----6)-beta-D-glucopyranoside (29), allyl O-(2-acetamido-2-deoxy-beta-D-glucopyranosyl-(1----2)-alpha-D- mannopyranosyl-(1----6)-beta-D-glucopyranoside (31), and allyl O-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-(1----2)-O-alpha-D- mannopyranosyl-(1----6)-O-beta-D-glucopyranosyl-(1----4)-beta-D-gluco pyr anoside (33). A common glycosyl donor, namely, 2-O-(2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-beta-D- glucopyranosyl)-3,4,6-tri-O-acetyl-alpha-D-mannopyranosyl bromide was employed for the synthesis of 27, 29, 31, and 33, the structures of which were all established by 13C-n.m.r. spectroscopy.

Separation by liquid chromatography (under elevated pressure) of benzyl and nitrophenyl glycosides of oligosaccharides

Liquid chromatography under elevated pressure (l.c.) was employed for the separation of some benzyl and nitrophenyl glycosides of a variety of mono-, di-, tri-, and tetra-saccharides. The separation was conducted on a Waters Carbohydrate Analysis column by use of a mixture of acetonitrile-water as the mobile phase. In general, monosaccharides emerged first from the column, followed sequentially by di-, tri-, and tetra-saccharides. It was observed that the pattern of substitution imparts a noticeable effect on the elution profiles of isomeric oligosaccharides. Also, substitution of a hydroxyl group with a methyl group, or its replacement with a fluorine atom, led to a substantial decrease in retention times of some oligosaccharides. Moreover, resolution was clearly enhanced, and retention times were congruently increased by decreasing the water content of the mobile phase.