radiation degradation of chitosan is one of the most important methods to prepare antibacterial oligochitosans. in this study, the effect of solvent on the reduction of degradation dose and enhancement of the antibacterialactivity of chitosan against pectobacterium carotovorum (pc) has been considered.gamma radiation degradation was applied to chitosan as solid and aqueous solution at dose rang...

Synthesis of amphiphilic, cyclic di- and tetrasaccharides, which incorporate a methylene moiety at the inter-glycosidic bond, is reported. The amphiphilic properties of the new cyclic tetrasaccharide host were identified through assessing the solubilities of guests in aqueous and in organic solvents. The glycosidic bond stability of the cyclic tetrasaccharide under aqueous acidic condition was ...

Two new nikkomycins were isolated from the fermentation broth of Streptomyces tendae Tü 901/PF 53+-3. These new metabolites, nikkomycins pseudo-Z (psi-Z,1) and pseudo-J (psi-J, 2) differ from the corresponding nikkomycins Z and J by a C-glycosidic bond between C-5 of uracil and C-1' of 5-amino-5-deoxy-D-allo-furanuronic acid instead of an N-glycosidic bond. The structure elucidation was achieve...

Patterns of scissile bond twisting have been found in crystal structures of glycoside hydrolases (GHs) that are complexed with substrates and inhibitors. To estimate the increased potential energy in the substrates that results from this twisting, we have plotted torsion angles for the scissile bonds on hybrid Quantum Mechanics::Molecular Mechanics energy surfaces. Eight such maps were construc...

To elucidate the contribution of pyrimidine in DNA strand breaks caused by low-energy electrons (LEEs), theoretical investigations of the LEE attachment-induced C(3')-O(3'), and C(5')-O(5') σ bond as well as N-glycosidic bond breaking of 2'-deoxycytidine-3',5'-diphosphate and 2'-deoxythymidine-3',5'-diphosphate were performed using the B3LYP/DZP++ approach. The base-centered radical anions are ...

The lack of robust, high-throughput, and sensitive analytical strategies that can conclusively map the structure of glycans has significantly hampered progress in fundamental and applied aspects of glycoscience. Resolution of the anomeric α/β glycan linkage within oligosaccharides remains a particular challenge. Here, we show that "memory" of anomeric configuration is retained following gas-pha...

A method is described to obtain multicollision dissociation threshold (MCDT) values. These values provide relative reaction thresholds for dissociation in the three major gas-phase fragmentation reactions of oligosaccharides complexed to alkali metal ions. The quasimolecular ions are produced using matrix-assisted laser desorption/ionization Fourier transform mass spectrometry. The MCDTs for al...

The gas-phase conformations of protonated uridine, [Urd+H](+), and its 2'-deoxy form, protonated 2'-deoxyuridine, [dUrd+H](+), have been examined in detail previously by infrared multiple photon dissociation action spectroscopy techniques. Both 2,4-dihydroxy tautomers and O4 protonated conformers of [Urd+H](+) and [dUrd+H](+) were found to coexist in the experiments with the 2,4-dihydroxy tauto...