黄土高原丘陵区不同生境小叶杨人工林物种多样性及其群落稳定性分析

通过样地调查,对黄土高原丘陵沟壑区处于阴坡、半阴坡、半阳坡、阳坡4种生境条件下,经过30年发育的小叶杨人工林物种多样性,群落结构动态和土壤水分养分效应进行了系统研究,结果表明:(1)不同生境小叶杨人工林总体上物种丰富度、多样性指数和均匀度指数均呈现出阴坡>半阴坡>半阳坡>阳坡的趋势,且林内物种多样性指数表现为:草本层>灌木层;(2)不同生境条件下的小叶杨人工林年龄结构分析表明,尽管阴坡小叶杨长势相对较好,但更新幼苗数量相当有限,很难实现种群的自我更新,不适合作为人工林培育;(3)土壤含水量和养分因坡向不同而呈现出明显的差异,尽管阴坡和半阴坡的水分、养分条件相对较好,但也出现了枯梢、病虫害等衰老特征,因此阴坡、半阴坡的生境对小叶杨来说也不合适.未来应该对现有林地在保护的前提下,间伐衰老个体,补植和引入乡土物种,进行天然化培育.     

辣椒雄性不育系SDH4基因的表达特性分析

为了探究线粒体电子传递复合体Ⅱ的关键酶基因(SDH4)与辣椒细胞质雄性不育的关系,该试验通过GenBank报道的辣椒线粒体基因组序列,特异引物扩增SDH4基因,并通过分析SDH4基因的时空表达及转录本编辑位点,以期找到辣椒细胞质雄性不育系9704A和保持系9704B的差异。结果表明:(1)从辣椒细胞质雄性不育系9704A和保持系9704B中获得的目的基因编码区片段长度一致,全长均为378bp,编码125个氨基酸残基。(2)辣椒保持系不同组织中SDH4基因表达存在差异,种子中表达最高,茎中表达最低。(3)在不同材料花蕾发育的同一时期,SDH4基因表达也不一致,在花粉母细胞减数分裂时期,不育系SDH4基因表达量明显低于保持系;而在造孢细胞增殖期、小孢子单核期和小孢子成熟期的表达量均高于保持系。(4)不育材料中SDH4基因在29位点出现RNA编辑,导致氨基酸由丝氨酸变为亮氨酸,增强了蛋白结构的疏水性能。研究认为,辣椒细胞质雄性不育系9704A和保持系9704B中SDH4基因的表达差异可能引起植物的能量代谢供应出现异常,从而导致雄性不育的产生。     

Neuroprotective effect of formononetin in ameliorating learning and memory impairment in mouse model of Alzheimer’s disease

Alzheimer’s disease (AD) is the most common cause of dementia among elderly population. Deranged β-amyloid (Aβ) trafficking across the blood–brain barrier is known to be a critical element in the pathogenesis of AD. In the vascular endothelial cells of hippocampus, Aβ transport is mainly mediated by low-density lipoprotein-associated protein 1 (LRP1) and the receptor for advanced glycation end (RAGE) products; therefore, LRP1 and RAGE endothelial cells are potential therapeutic targets for AD. In this study, we explored the effects of Formononetin (FMN) on learning and memory improvement in APP/PS1 mice and the related mechanisms. We found that FMN significantly improved learning and memory ability by suppressing Aβ production from APP processing, RAGE-dependent inflammatory signaling and promoted LRP1-dependent cerebral Aβ clearance pathway. Moreover, FMN treatment alleviated ultrastructural changes in hippocampal vascular endothelial cells. In conclusion, we believe that FMN may be an efficacious and promising treatment for AD.     

Preparation of konjac glucomannan hydrogels as DNA-controlled release matrix

In this study, hydrogels for DNA-controlled release was prepared with konjac glucomannan (KGM), a water-soluble non-ionic polysaccharide, by means of deacetylated reaction and physically cross-linking method under mild conditions. The properties of the KGM hydrogels were analyzed by FTIR spectra and scanning electron microscopy (SEM). The integrality of the released DNA was investigated by circular dichroism (CD). The DNA release kinetics was performed using the DNA-loaded KGM gels in buffer solutions of pH 7.4 at 37+/-0.5 degrees C. Peppas model and Higuchi model were used to analysis the DNA release mechanism; the data indicated that the DNA release can be controlled by changing the preparation conditions and the structure parameters of the gels. This study suggested that the KGM hydrogels have a potential use for advanced controlled release.     

叶子花花瓣状苞片和叶片的比较转录组学研究

叶子花(Bougainvillea spectabilis Willd.)的苞片色彩鲜艳,呈花瓣状,在景观园艺和环境美化有着广泛应用。为了进一步了解花瓣状苞片的演化机制,该研究采用RNA-seq技术分别对苞片和叶片进行测序,比较苞片和叶片在基因表达水平的差异。最终获得54.48 M对长度为150bp的双向clean reads,从头拼接出55 782条Unigenes,平均长度为1 003.79bp,N50为1 402bp。共有30 874条Unigenes能被注释到公共数据库,其中有12 631条Unigenes能被注释到基因本体。差异化表达分析确定苞片和叶片差异表达的基因共有456个。该研究分别对不同组织差异表达的基因进行GO富集分析和KEGG富集分析,结果表明,在苞片中高表达的差异化基因有黄酮类合成相关的基因,花色合成关键酶多巴双加氧酶(DODA)以及发现与花瓣发育相关的基因,在叶片中高表达的差异化基因主要是参与光合作用。     

城市生态用地分类及其规划的一般原则

城市生态用地的规划布局是城市规划的难点之一,也是急待解决的问题.本文根据城市生态系统的特点,给出了城市生态用地定义,指出城市生态用地同时具有自然属性和社会属性,依据这个特点,将城市生态用地划分为服务型生态用地和功能型生态用地两大类型,并结合具体的城市生态规划对各种类型的生态用地规划进行了定性分析.     

GSK-3在阿尔茨海默病样细胞骨架蛋白过度磷酸化中的作用(英)

神经原纤维缠结是阿尔茨海默病（Alzheimer disease, AD）的特征性病理改变.蛋白激酶和蛋白磷酸酯酶失衡可导致骨架蛋白的异常过度磷酸化,而异常过度磷酸化的tau 和神经丝 (neurofilament, NF) 是神经原纤维缠结的组成部分.在众多激酶中,糖原合酶激酶-3（glycogen synthase kinase-3,GSK-3）可能是AD神经退行性变起重要作用.为深入探讨GSK-3在AD样神经退行性变中的作用,以磷酯酰肌醇三磷酸激酶（phosphatidylinositol 3-kinase,PI3K）的特异性抑制剂渥曼青霉素（wortmannin,WT）处理野生型鼠成神经瘤细胞株（wild type mouse neuroblastoma cell lines, N2a wt）,系统观察WT处理N2a wt不同时间点（1 h、3 h、6 h）细胞代谢率、细胞形态、细胞骨架蛋白tau和NF的磷酸化状态改变以及细胞的命运,并分析了GSK-3活性与上述参数改变之间的相关性.结果发现：1 μmol/L WT处理细胞1 h,GSK-3活性与未经WT处理的对照组相比明显增高,并伴有Ser9磷酸化的GSK-3水平的降低; NF磷酸化程度增强,tau在Ser198/Ser199/Ser202位点的磷酸化增强. 1 μmol/L WT处理细胞3 h,GSK-3活性与对照组和处理1 h 组相比明显下降,NF磷酸化程度较1 h降低,但仍高于正常水平.1 μmol/L WT处理细胞6 h,细胞形态、GSK-3活性、Ser9磷酸化形式的GSK-3β的表达、NF磷酸化程度与对照组相比均无明显改变.WT呈剂量依赖性降低细胞代谢率.1 μmol/L WT处理细胞1 h和3 h导致细胞变圆,突起变短甚至消失.1 μmol/L WT处理细胞1 h,用TUNEL法和电子显微镜技术未观察到细胞凋亡.研究结果提示：在N2a细胞中过度激活GSK-3可导致神经细丝和tau蛋白的AD样过度磷酸化,从而引起神经细胞的AD样退行性变.     

Expression of chemokine-like factor 1 is upregulated during T lymphocyte activation

Chemokine-like factor 1 (CKLF1) is a cytokine with chemotactic effects on leukocytes and a functional ligand of CCR4. This cytokine is widely expressed and the level of expression is reported to be upregulated in asthma and rheumatoid arthritis (RA), disease conditions in which T lymphocytes are over-activated. In order to determine the expression profile of CKLF1 in activated T lymphocytes, we first employed a PCR-based method on human blood fractions cDNA panels and found that CKLF1 was upregulated in activated CD4+ and CD8+ cells, with no obvious changes in CD19+ cells. We further performed kinetic analyses of CKLF1 expression in phytohemagglutinin (PHA)-stimulated human peripheral blood lymphocytes (PBL) at both the mRNA and protein levels. In resting PBL, the constitutive expression of CKLF1 was low at mRNA level and barely detectable at the protein level; however, both were remarkably upregulated by PHA, appearing at 8h after PHA-stimulation and persisting up to 72h. These results suggest that CKLF1 may be involved in T lymphocyte activation and further study of CKLF1 function will prove valuable.