葡基胺香料化合物的制备及应用研究

采用了一种简单、易控的方法,以葡萄糖和NH4HCO3为原料、NaOH—无水甲醇为溶剂与催化剂合成了在通常条件下较难控制合成的前体香料化合物—葡基胺,并提出了合成葡基胺的较佳条件在该条件下,葡基胺的产率可达73%。利用该产物对造纸法烟草薄片进行加香试验还表明,它具有较好的掩盖薄片木质杂气和增强烟香的效果。

Resolving Ketoprofen Using n-Octyl-d-glucamine as an Optical Resolution Agent

The process of resolution of racemic ketoprofen using n-octyl-d-glucamine as an optical resolution agent was investigated. The process consists of preparation of the diastereomer salt of ketoprofen with n-octyl-d-glucamine, liberation of S-(+)-ketoprofen from its diastereomer salt and recovery of the remaining ketoprofen and n-octyl-d- glucamine. The suitable conditions for preparation of the diastereomer salt were methanol and ethyl acetate (1.1 by volume) as the solvent, the ratio of solvent volume to ketoprofen mass at 8ml:1g, and the molar ratio of ketoprofen to n-octyl-d-glucamine at 1:1. The preferred approach to liberate S-(+)-ketoprofen from its diastereomer salt was alkali dissolution, acid adjustment and ethyl acetate extraction. Racemization of the recovered ketoprofen could be achieved by reacting the recovered ketoprofen with 10% NaOH at 507 kPa for 6h. The recovered n-octyl-d- glucamine could be refined by acid dissolution and alkali adjustment. S-(+)-ketoprofen can be obtained with high optical purity and yield, showing that the present process is a practical and efficient one which can be used in industrial scale for preparation of S-(+)-ketoprofen.

Adsorption Kinetics of Decanoyl-N-methylglucamine at the Expanding Spherical Surface

A general expression of the dynamic surface adsorption [Г（t）] on the expanding spherical surface was derived by solving the corresponding diffusion equation under different initial and boundary conditions. Different from the result of the still spherical surface, two factors （smaller than 1） appeared in the equation for the short time adsorption. Using the derived results, the adsorption kinetics of aqueous decanoyl-N-methylglucamine （Mega-10） solution was studied. In the short time region （t→0）, a good agreement of experimental results with the theory was reached and the adsorption was controlled by diffusion.

HCV NS5A and NS5B Enhance Expression of Human Ceramide Glucosyltransferase Gene

Host genes involved in lipid metabolism are differentially affected during the early stages of hepatitis C virus （HCV） infection. Here we demonstrate that artificial up-regulation of fatty acid biosynthesis has a positive effect on the replication of the HCV full-length replicon when cells were treated with nystatin. Conversely, the HCV RNA replication was decreased when fatty acid biosynthesis was inhibited with 25-hydroxycholesterol and PDMP（D-threo-l-phenyl-2-decanoylamino-3- morpholino-l-propanol）. In agreement with these results, the expression level of GlcT-l（ceramide glucosyltransferase）, a host glucosyltransferase in the first step of GSL （glycosphingolipid） biosynthesis, was found to be closely associated with the expression and replication of HCV RNA. On the other hand, the viral RNA can also activate GlcT-1 in the early stage of viral RNA transfection in vitro. To identify viral factors that are responsible for GlcT-1 activation, we constructed ten stable Vero cell lines that express individual HCV proteins. Based on the analyses of these cell lines and transient transfection assay of the GlcT-1 promoter regions, we conclude that HCV proteins, especially NS5A and NS5B, have positive effects on the expression of GlcT-1. It is possible that NS5A and NS5B stimulate transcription factor（s） to activate the expression of GlcT-1 by increasing its transcription level

O-linked β-N-acetylglucosamine modification and its biological functions

The covalent attachment of O-linked β-N- acetylglucosamine （O-GIcNAc） to Ser/Thr residues of proteins acts as not only a posttranslational modification but also a nutritional sensor in nucleus and cytoplasm, which directly regulates the expression of genes and multiple crucial signal transduction pathways. Dynamic O- GlcNAcylation at Ser/Thr residues is catalyzed by two key enzymes, O-GIcNAc transferase （OGT） and O-GlcNAcase, which are responsible for addition and removal of the O- GlcNAc modification, respectively. O-GlcNAc modifica- tion plays important roles in cellular signaling in animals, especially in human diseases. Two orthologs of OGT in plants, SECRET AGENT and SPINDLY, have been reported to be involved in diverse plant processes. However, compared with the functional mechanisms revealed in animals, the consequences of protein O-GlcNAc modifi- cation in plants is largely unknown, and the relationship between O-GlcNAcylation and cellular processes needs to be explored. In this review, we summarized the recent advances on O-GlcNAc modification and its biological functions in animals and plants, and prospect of more special functions of O-GlcNAc will be revealed in plants.