Search results for "Amino Sugars"
showing 3 items of 3 documents
Glycosyl azides as building blocks in convergent syntheses of oligomeric lactosamine and Lewisx saccharides
1997
Abstract Oligosaccharides containing type 2 lactosamine repeating units, e.g. neo-lacto-octaose and trimeric Lewis x derivatives, are constructed using neo-lactosamine azide building blocks. The azido group provides a favorable protection of the anomeric position which is stable to versatile protecting group manipulations and glycosylation reactions. On the other hand, glycosyl azides can be converted into glycosyl fluorides via a 1,3-dipolar cycloaddition with di- tert -butyl-acetylenedicar☐ylate and subsequent treatment of the resulting N -glycosyl triazoles with hydrogen fluoride-pyridine complex. Activation of the lactosamine fluorides with Lewis acids affords the possibility to extend …
Natural Organic Compounds in Soil Solution: Potential Role as Soil Quality Indicators
2013
This review focuses on the chemical nature of that fraction of already dissolved organic matter into soil solution, or extracted by mild extractants, which is truly readily available for microbial activity and, consequently, more sensitive than total soil organic matter to changes in management and/or environmental conditions. In particular, we deal with low molecular weight compounds such as monosaccharides, amino sugars and amino acids. Soil sampling strategy and extraction procedure, prior to analyses, are crucial to make comparable results among laboratories. Although soil management and climatic conditions may cause large variability, extractable organic C and N may indicate the amount…
The lactose operon from Lactobacillus casei is involved in the transport and metabolism of the human milk oligosaccharide core-2 N-acetyllactosamine
2018
The lactose operon (lacTEGF) from Lactobacillus casei strain BL23 has been previously studied. The lacT gene codes for a transcriptional antiterminator, lacE and lacF for the lactose-specific phosphoenolpyruvate: phosphotransferase system (PTS) EIICB and EIIA domains, respectively, and lacG for the phospho-β-galactosidase. In this work, we have shown that L. casei is able to metabolize N-acetyllactosamine (LacNAc), a disaccharide present at human milk and intestinal mucosa. The mutant strains BL153 (lacE) and BL155 (lacF) were defective in LacNAc utilization, indicating that the EIICB and EIIA of the PTS are involved in the uptake of LacNAc in addition to lactose. Inactivation of lacG aboli…