The sialylation of the oligosaccharides from small-intestinal mucins during a 13-day infectious cycle was studied in Sprague-Dawley rats with the parasite Nippostrongylus brasiliensis. Sialic acid analysis and release, permethylation and analysis by GC-MS of the sialylated oligosaccharides isolated from the 'insoluble' mucin complex revealed a relative decrease (4-7-fold) of N-glycolylneuramini...

This study aimed to compare the metabolic profile of unstimulated (US) and stimulated (SS) saliva samples from pregnant women with/without obesity periodontitis. Ninety-six were divided into: + periodontitis (OP = 20); obesity/no (OWP 27); normal BMI (NP BMI/no (NWP 29). US SS collected by expectoration chewing sterilized parafilm gum, respectively, individually analyzed Proton Nuclear Magnetic...

-l. Detailed chemical analyses are presented of the protein material precipitating from rat milk at pH 4.0. 2. Like bovine and human casein, this material contains carbohydrates (fucose, galactose, galactosamine and N-acetylneuraminic acid) and phosphorus. 3. Its amino acid composition is similar to those of bovine and human casein; but it has much higher levels of alanine and serine and much l...

Permethylated derivatives of N-acetylneuraminic acid-containing GM3, N-glycolylneuraminic acid-containing GM3, GD1a, and GD1b, were analyzed by direct inlet ammonia chemical ionization (CI) mass spectrometry. These compounds were found to yield simple fragmentations, prominent fragment ions in the high mass region, and characteristic fragment ions corresponding to the cleavage of glycosidic lin...

The acquisition of host-derived sialic acid is an important virulence factor for some bacterial pathogens, but in vivo this sugar acid is sequestered in sialoconjugates as the alpha-anomer. In solution, however, sialic acid is present mainly as the beta-anomer, formed by a slow spontaneous mutarotation. We studied the Escherichia coli protein YjhT as a member of a family of uncharacterized prot...

In the present Communication, we propose a quite simple but previously overlooked approach for conveniently analyzing, assigning, and extracting sialic acid-containing N-glycan structures using high-resolution NMR spectroscopy without pre-installing metal chelators. Paramagnetic metals, such as Gd3+, appear to bind to the carboxyl groups of N-acetylneuraminic acid when introduced at room temper...

A simple protocol for the synthesis of N-perfluoroacylated and N-acylated glycals of neuraminic acid, with a secondary cyclic amine (morpholine or piperidine) at the 4α position, has been set-up, starting from peracetylated N-acetylneuraminic acid methyl ester that undergoes, sequentially to its direct N-transacylation followed by a C-4 amination, a β-elimination, and a selective hydrolysis of ...

Considerable interest has been manifest in the biosynthesis of protein-carbohydrate complexes as a result of the demonstration of their wide distribution in mammalian organs and body fluids. In recent years, significant progress has been made toward the elucidation of the chemical structure of plasma glycoproteins (l-5) in which the cardinal role of N-acetylglucosamine and N-acetylneuraminic ac...