Properties of resorcinol-tannin-formaldehyde copolymer resins prepared from the bark extracts of Taiwan acacia and China fir

Resorcinol-tannin-formaldehyde copolymer resins (RTF) were prepared by using the bark extracts of Taiwan acacia (Acacia confusa) and China fir (Cunninghamia lanceolata) to substitute part of the resorcinol. From the results, the content of reactive phenolic materials in Taiwan acacia and China fir bark extracts were 51.6% and 46.5%, respectively. Aromatic compounds were the main components in the bark extracts showed by FT-IR analysis. The conventional synthesis condition used for RF resin was certainly not suitable for the RTF copolymer resin. It should be formed the novolak RF prepolymer by reacting the resorcinol with formaldehyde at the first stage, and then the bark extracts added and underwent the copolymerization reaction under acidic condition at the second-stage. The RTF copolymer resins prepared had cold-setting capability. They had higher viscosity, shorter gel time as compared with the RF resin. The RTF copolymer resins could be carried out the gluing application immediately after the hardener was added and had bonding strength the same as RF resin. But the RTF copolymer resins had worse stability and shorter shelf life than RF resin.     

Discovery of potent, selective, and orally bioavailable pyridone-based dipeptidyl peptidase-4 inhibitors

anti-Substituted beta-methylphenylalanine derived amides have been shown to be potent DPP-IV inhibitors exhibiting excellent selectivity over both DPP8 and DPP9. The optimized compound exhibited good pharmacokinetic profiles in three preclinical species.     

N',2-diphenylquinoline-4-carbohydrazide based NK3 receptor antagonists

A new class of potent NK3R antagonists based on the N',2-diphenylquinoline-4-carbohydrazide core is described. In an ex vivo assay in gerbil, the lead compound 2g occupies receptors within the CNS following oral dosing (Occ(90) 30 mg/kg po; plasma Occ(90) 0.95 microM) and has good selectivity and promising PK properties.     

Synthesis and pharmacological activities of xanthone derivatives as alpha-glucosidase inhibitors

Considerable interest has been attracted in xanthone and its derivatives because of their large variety of pharmacological activities. In this project, a series of hydroxylxanthones and their acetoxy and alkoxy derivatives were synthesized and evaluated as alpha-glucosidase inhibitors, aimed at clarifying the structure-activity correlation. The results indicated that these xanthone derivatives were capable of inhibiting in vitro alpha-glucosidase with moderate to good activities. Among them, polyhydroxylxanthones exhibited the highest activities and thus may be exploitable as a lead compound for the development of potent alpha-glucosidase inhibitors.     

Arabidopsis thaliana wild type, pho1, and pho2 mutant plants show different responses to exogenous cytokinins.

Despite the involvement of cytokinins in phosphate (Pi) signaling being highlighted, the physiological processes involved remain unclear. In this study, we have evaluated the effect of cytokinins on different physiological responses using wild type (wt) and two Arabidopsis mutants with altered shoot Pi content (pho1 and pho2). Physiological studies were related with those previously described as cytokinin-regulated: including hypocotyl elongation, root growth, anthocyanin accumulation, senescence and relative gene expression. Generally, pho1 mutants showed decreased sensitivity to cytokinin, whereas pho2 mutants showed increased sensitivity to the hormone. This observation applies to inhibition of hypocotyls and root growth and anthocyanin accumulation. However, this effect was not shown during senescence or in the expression of ARR6 (Arabidopsis response regulator, ARR). Interestingly, Pi content in shoot of pho1 mutants increased to wt levels after treatment with cytokinins. These results suggest that the interaction between phosphate signaling and cytokinin signaling may be bidirectional while the differential behavior in response to cytokinin is discussed further.     

Reovirus mu1 structural rearrangements that mediate membrane penetration

Membrane penetration by nonenveloped reoviruses is mediated by the outer-capsid protein, mu1 (76 kDa). Previous evidence has suggested that an autolytic cleavage in mu1 allows the release of its N-terminally myristoylated peptide, mu1N (4 kDa), which probably then interacts with the target-cell membrane. A substantial rearrangement of the remaining portion of mu1, mu1C (72 kDa), must also have occurred for mu1N to be released, and some regions in mu1C may make additional contacts with the membrane. We describe here a particle-free system to study conformational rearrangements of mu1. We show that removal of the protector protein sigma3 is not sufficient to trigger rearrangement of free mu1 trimer and that free mu1 trimer undergoes conformational changes similar to those of particle-associated mu1 when induced by similar conditions. The mu1 rearrangements require separation of the mu1 trimer head domains but not the mu1N/C autocleavage. We have also obtained a relatively homogeneous form of the structurally rearranged mu1 (mu1*) in solution. It is an elongated monomer and retains substantial alpha-helix content. We have identified a protease-resistant approximately 23-kDa fragment of mu1*, which contains the largely alpha-helical regions designated domains I and II in the conformation of mu1 prior to rearrangement. We propose that the mu1 conformational changes preceding membrane penetration or disruption during cell entry involve (i) separation of the beta-barrel head domains in the mu1 trimer, (ii) autolytic cleavage at the mu1N/C junction, associated with partial unfolding of mu1C and release of mu1N, and (iii) refolding of the N-terminal helical domains of mu1C, with which mu1N was previously complexed, accompanied by dissociation of the mu1 trimer.     

Catalpol protects dopaminergic neurons from LPS-induced neurotoxicity in mesencephalic neuron-glia cultures

Inflammation plays an important role in the pathogenesis of Parkinson's disease (PD). Microglia, the resident immune cells in the central nervous system, are pivotal in the inflammatory reaction. Activated microglia can induce expression of inducible nitric-oxide synthase (iNOS) and release significant amounts of nitric oxide (NO) and TNF-alpha, which can damage the dopaminergic neurons. Catalpol, an iridoid glycoside, contained richly in the roots of Rehmannia glutinosa, was found to be neuroprotective in gerbils subjected to transient global cerebral ischemia. But the effect of catalpol on inflammation-mediated neurodegeneration has not been examined. In this study, microglia in mesencephalic neuron-glia cultures were activated with lipopolysaccharide (LPS) and the aim of the study was to examine whether catalpol could protect dopaminergic neurons from LPS-induced neurotoxicity. The results showed that catalpol significantly reduced the release of reactive oxygen species (ROS), TNF-alpha and NO after LPS-induced microglial activation. Further, catalpol attenuated LPS-induced the expression of iNOS. As determined by immunocytochemical analysis, pretreatment by catalpol dose-dependently protected dopaminergic neurons against LPS-induced neurotoxicity. These results suggest that catalpol exerts its protective effect on dopaminergic neurons by inhibiting microglial activation and reducing the production of proinflammatory factors. Thus, catalpol may possess therapeutic potential against inflammation-related neurodegenerative diseases.     

Development of rabbit monoclonal and polyclonal antibodies for detection of site-specific histone modifications and their application in analyzing overall modification levels

In addition to DNA sequence information,site-specific histone modifications are another important determinant ofgene expression in a eukaryotic organism.We selected four modification sites in common histones that are known tosignificantly impact chromatin function and generated monoclonal or polyclonal antibodies that recognize each of thosesite-specific modifications.We used these antibodies to demonstrate that the site-specific histone modification levelsremain relatively constant in different organs of the same organism.We also compared the levels of selected histonemodifications among several representative organisms and found that site-specific modifications are highly variable amongdifferent organisms,providing new insight into the evolutionary divergence of specific histone modifications.     

滇西北香格里拉县大型真菌资源及其利用现状

香格里拉县（中旬县）位于云南省西北部,该区域内地形地貌复杂,海拔高差悬殊,兼有温带和寒温带高山气候类型。该区具有典型的温性、寒温性针叶林和寒温性常绿阔叶林以及针阔混交林,其中有不少是能与大型真菌形成共生关系的树种,如云南松（Pinus yunnanensis Franch．）、高山松（P．densata Mast．）、川滇高山栎（Quercus aquifolioides Rehd．etWils．）、灰背栎（Q．senescens Hand．-Mazz．）以及高山桦（Betula delavayi Franch．）和白桦（B．platyphylla Suk．）等。     

TBa多克隆抗体的制备及其重组蛋白免疫活性的鉴定

目的:TBa(tartary buckwheat allergen)是苦荞麦中的主要过敏原。为了研究TBa的结构与功能关系并鉴定其重组蛋白的特异性免疫活性。方法:采用之前从种子中分离纯化的天然TBa作为抗原免疫小鼠,制备抗血清,建立了类似竞争酶联免疫吸附检测TBa的分析方法。结果:对重组TBa的免疫活性鉴定表明,采用该方法制备的多克隆抗体能满足重组TBa的免疫活性鉴定,这为下一步研究其免疫学功能奠定了基础。