New triazole derivatives as antifungal agents: synthesis via click reaction, in vitro evaluation and molecular docking studies

A series of 1-(1H-1,2,4-triazol-1-yl)-2-(2,4-difluorophenyl)-3-substituted-2-propanols (5a-5y) which are analogues of fluconazole, have been designed and synthesized via Cu(I)-catalyzed azide-alkyne cycloaddition on the basis of computational docking experiments to the active site of the cytochrome P450 14α-demethylase (CYP51). The in vitro antifungal activities of all the target compounds were evaluated against eight human pathogenic fungi. Compound 5l showed the best antifungal activities.     

不同氮源对球形棕囊藻生长的影响

采用实验室培养的方法比较了6种不同氮源-硝态氮、尿素、甘氨酸、精氨酸、谷氨酸、腺嘌呤对典型赤潮藻球形棕囊藻(Phaeocystis globosa)生长的影响。结果表明,6种氮源均能不同程度地促进球形棕囊藻的生长,但比生长速率和光合作用效率具有显著差异性。将球形棕囊藻在不同浓度氮源下的最大比生长速率分别拟合Monod方程,得出球形棕囊藻在硝态氮、尿素、甘氨酸、精氨酸、谷氨酸和腺嘌呤等6种氮源下的最大比生长率分别为1.05,1.17,0.82,0.87,1.09,0.90d^-1,相应的半饱和常数分别为9.132,23.758,85.519,7.104,23.94,10.959μmol/L。其中,高氮浓度(8820μmol/L)下腺嘌呤对球型棕囊藻的生长具有显著抑制作用。相比较而言,球形棕囊藻对甘氨酸的亲和力最高。当硝态氮、尿素、甘氨酸、精氨酸、谷氨酸和腺嘌呤的浓度分别为8820,882,882,8820,882,0.441μmol/L时,球形棕囊藻的最大光合效率(Fv/Fm)分别为0.619,0.620,0.579,0.595,0.648,0.667。由此可见,氮源对球形棕囊藻的生长和光合作用具有显著影响;球形棕囊藻能够利用多种无机和有机氮源,与其它仅能利用无机氮源的浮游植物相比,更具有竞争优势。     

VEGF165 induces differentiation of hair follicle stem cells into endothelial cells and plays a role in in vivo angiogenesis

Within the vascular endothelial growth factor (VEGF) family of five subtypes, VEGF165 secreted by endothelial cells has been identified to be the most active and widely distributed factor that plays a vital role in courses of angiogenesis, vascularization and mesenchymal cell differentiation. Hair follicle stem cells (HFSCs) can be harvested from the bulge region of the outer root sheath of the hair follicle and are adult stem cells that have multi‐directional differentiation potential. Although the research on differentiation of stem cells (such as fat stem cells and bone marrow mesenchymal stem cells) to the endothelial cells has been extensive, but the various mechanisms and functional forms are unclear. In particular, study on HFSCs’ directional differentiation into vascular endothelial cells using VEGF165 has not been reported. In this study, VEGF165 was used as induction factor to induce the differentiation from HFSCs into vascular endothelial cells, and the results showed that Notch signalling pathway might affect the differentiation efficiency of vascular endothelial cells. In addition, the in vivo transplantation experiment provided that HFSCs could promote angiogenesis, and the main function is to accelerate host‐derived neovascularization. Therefore, HFSCs could be considered as an ideal cell source for vascular tissue engineering and cell transplantation in the treatment of ischaemic diseases.     

官山白颈长尾雉活动区域海拔高度的季节变化及其影响因素

2005年7月至2006年12月,采用无线电遥测的方法在江西官山国家级自然保护区内对5只白颈长尾雉（Syrmaticus ellioti）的活动区域进行了跟踪监测,结合GIS技术和样方法分析其活动区域的海拔高度随季节变化的影响因素。结果表明：海拔400-600m为白颈长尾雉全年最适活动带,其主要活动区域的海拔高度呈现明显的季节变化：夏秋季最高,春季次之,冬季最低。水源是其冬季喜欢在低海拔区域活动的最主要原因;而距林缘距离、灌木数量、灌木种数、灌木盖度等与增加食物丰富度和隐蔽度相关的因子是促使它们在春季和夏秋季倾向于在高海拔区域活动的主要因素。     

四川白水河国家级大熊猫自然保护区生态旅游发展战略研究

通过对白水河国家级自然保护区生态旅游资源的参与式调查与评估,确定了白水河生态旅游的可行的优先区域,比选出本区生态旅游资源特色,提出了白水河生态旅游“以大熊猫栖息地探秘、观鸟、生态教育与体验为核心的生态旅游目的地”的主题定位,以及“飞来的大熊猫原生栖息地”等形象定位,以及生态旅游活动布局,价格策略、营销策略、管理策略等战略。     

Novel symmetric amphiphilic dendritic poly(L-lysine)-b-poly(L-lactide)-b-dendritic poly(L-lysine) with high plasmid DNA binding affinity as a biodegradable gene carrier

This study communicates the molecular design, preparation, and biological application of novel symmetric amphiphilic polycationic dendritic poly(L-lysine)-b-poly(L-lactide)-b-dendritic poly(L-lysine) D2-LLA15-D2 bearing two two-generation poly(L-lysine) PLL dendrons D2 and a central hydrophobic biodegradable poly(L-lactide) block LLA15. First, an amino-protected precursor of L1-OH was designed and synthesized and was further employed to prepare L1-LLA15 with an organic 4-(dimethylamino)-pyridine-mediated living-ring-opening polymerization of l-lactide. Subsequently, the hydroxy end-capped L1-LLA15 was coupled to synthesize a new triblock L1-LLA15-L1 with two one-generation amino-protected PLL dendrons L1. Furthermore, with a repeated trifluoroacetic-acid-mediated amino deprotection-protection cycle, new amphiphilic triblock D2-LLA15-D2 was successfully prepared. By means of NMR, mass spectrometry, and gel permeation chromatography, these synthetic precursors and final amphiphilic product were characterized to bear well-defined triblock structures. In addition, this synthesized amphiphilic triblock polycationic macromolecule was applied as a new polycationic plasmid DNA carrier, and its DNA binding affinity was examined via an agarose electrophoresis and a fluorescence titration assay along with two important references of hydrophilic dendritic D2-HEX-D2 and double-hydrophilic D2-PEG-4K-D2 bearing the same two D2 dendrons; much enhanced DNA binding affinity was interestingly revealed for the new amphiphilic structural D2-LLA15-D2. Moreover, the assembled polyplex microparticles of plasmid DNA/polycationic carrier were further analyzed by dynamic light scattering and transmission electron microscopy, indicating their averaged nanoparticle size around 150-200 nm. As for the cytotoxicity of the new D2-LLA15-D2, MTT assays were conducted with a human hepatocellular carcinoma cell line (SMMC-7721), indicating a very low cytotoxicity as compared with commercial linear PLL-23K and PEI-2K, and a DNase I degradation of the assembled polyplex particles was also done in the HBS buffer solution to evaluate their stabilities. Finally, employing the new amphiphilic D2-LLA15-D2 as gene carrier, in vitro gene transfection experiments were conducted with the SMMC-7721 cell line, indicating a transfection efficiency increase of at least 10 times higher than that of the naked plasmid DNA under a N/P charge ratio of 10. Therefore, these interesting results may provide a new possible way to construct efficient polycationic macromolecular gene carriers with low toxicity and less expensive low-generation PLL dendrons.     

Effect of rock fragments on the percolation and evaporation of forest soil in Liupan Mountains, China

The water-retaining capacity, percolation and evaporation of stony soil in Liupan Mountains, China, were measured in order to understand the effect of rock fragments on soil hydrological processes. The results indicated that the effective water-retaining capacity of soil is positively related with the volumetric content of rock fragments, but there is no relation between saturated water-retaining capacity and rock fragment content. For the soil layers within 0–40 cm, the steady infiltration rate increases with increasing volumetric content of rock fragments until it reaches the range of 15%–20%, and then it decreases when the rock fragment content further increases. For the soil layers below 40 cm, the steady infiltration rate always increases with increasing rock fragment content. The soil evaporation rate decreases with increasing volumetric content of rock fragments when it varies in the range of 0–20%, while the soil evaporation rate keeps basically stable when the rock fragment content is higher than 20%. The soil evaporation rate shows a rising tendency with increasing size of rock fragments.