Carbohydrate Research 

Abstract: As a result of a study of the permethylation of sugars in such dipolar aprotic solvents as methyl sulphoxide, the hitherto accepted role of the CH3SOCH−2 anion is questioned. The HO− and H− ions appear to be the effective basic agents in these methylation reactions. This conclusion suggested a new method for the permethylation of sugars involving methyl iodide, a solid base (NaOH, KOH, or tert-BuOH/NaOH), and methyl sulphoxide. Excellent yields (98 ±2%) of permethylation products were obtained in a remarkably short (6–7 min) reaction time. The non-sugar peaks that appear in gas chromatograms of the products of Hakomori methylation were absent when the new reagent was used.

Abstract: A simple and rapid method is described for the preparation of alditol acetates from monosaccharides. It can be performed in a single tube without transfers or evaporations. Monosaccharides are reduced with sodium borohydride in dimethyl sulphoxide and the resulting alditols acetylated using 1-methylimidazole as the catalyst. Removal of borate is unnecessary and acetylation is complete in 10 min at room temperature. Monosaccharides are quantitatively reduced and acetylated by this procedure. The alditol acetates are completely separated by glass-capillary, gas-liquid chromatography on Silar 10C. The method has been applied to the analysis of monosaccharides in acid hydrolysates of a plant cell-wall.

Abstract: Chitosan nanoparticles, such as those prepared in this study, may exhibit potential antibacterial activity as their unique character. The purpose of this study was to evaluate the in vitro antibacterial activity of chitosan nanoparticles and copper-loaded nanoparticles against various microorganisms. Chitosan nanoparticles were prepared based on the ionic gelation of chitosan with tripolyphosphate anions. Copper ions were adsorbed onto the chitosan nanoparticles mainly by ion-exchange resins and surface chelation to form copper-loaded nanoparticles. The physicochemical properties of the nanoparticles were determined by size and zeta potential analysis, atomic force microscopy (AFM), FTIR analysis, and XRD pattern. The antibacterial activity of chitosan nanoparticles and copper-loaded nanoparticles against E. coli, S. choleraesuis, S. typhimurium, and S. aureus was evaluated by calculation of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Results show that chitosan nanoparticles and copper-loaded nanoparticles could inhibit the growth of various bacteria tested. Their MIC values were less than 0.25 microg/mL, and the MBC values of nanoparticles reached 1 microg/mL. AFM revealed that the exposure of S. choleraesuis to the chitosan nanoparticles led to the disruption of cell membranes and the leakage of cytoplasm.

Abstract: Plant cell walls consist of carbohydrate, protein, and aromatic compounds and are essential to the proper growth and development of plants. The carbohydrate components make up �90% of the primary wall, and are critical to wall function. There is a diversity of polysaccharides that make up the wall and that are classified as one of three types: cellulose, hemicellulose, or pectin. The pectins, which are most abundant in the plant primary cell walls and the middle lamellae, are a class of molecules defined by the presence of galacturonic acid. The pectic polysaccharides include the galacturonans (homogalacturonan, substituted galacturonans, and RG-II) and rhamnogalacturonan-I. Galacturonans have a backbone that consists of a-1,4-linked galacturonic acid. The identification of glycosyltransferases involved in pectin synthesis is essential to the study of cell wall function in plant growth and development and for maximizing the value and use of plant polysaccharides in industry and human health. A detailed synopsis of the existing literature on pectin structure, function, and biosynthesis is presented.