Effects of Revegetation on Soil Microbial Biomass,Enzyme Activities,and Nutrient Cycling on the Loess Plateau in China

Revegetation is a traditional practice widely used for soil and water conservation on the Loess Plateau in China. However, there has been a lack of reports on soil microbial–biochemical indices required for a comprehensive evaluation of the success of revegetation systems. In this study, we examined the effects of revegetation on major soil nutrients and microbial–biochemical properties in an artificial alfalfa grassland, an enclosed natural grassland, and an artificial shrubland (Caragana korshinskii), with an abandoned cropland as control. Results showed that at 0–5, 5–20, and 20–40 cm depths, soil organic carbon, alkaline extractable nitrogen and available potassium were higher in natural grassland and artificial shrubland compared with artificial grassland and abandoned cropland. Soil microbial biomass C (Cmic) and phosphorous (Pmic) substantially decreased with depth at all sites, and in abandoned cropland was significantly lower than those of natural grassland, artificial grassland, and artificial shrubland at the depth of 0–5 cm. Soil microbial biomass N (Nmic) was higher in artificial shrubland and abandoned cropland compared with that in natural and artificial grasslands. Both Cmic and Pmic were significantly different between the 23‐year‐old and the 13‐year‐old artificial shrublands at the 0–5 cm depth. The activities of soil invertase, urease, and alkaline phosphatase in natural grassland and artificial shrubland were higher than those in artificial grassland and abandoned cropland. This study demonstrated that the regeneration of both natural grassland and artificial shrubland effectively preserved and enhanced soil microbial biomass and major nutrient cycling, thus is an ecologically beneficial practice for recovery of degraded soils on the Loess Plateau.     

红藻氨酸癫痫大鼠海马GFAP基因调控蛋白表达的变化

目的和方法：用Southwestern印迹从红藻氨酸（KA）癫痫大鼠海马结构中筛选调控胶质原纤维酸性蛋白（GFAP）基因表达的DNA结合蛋白;并观察其在海马内表达变化的规律,旨在从基因调控水平深入探讨癫痫反复发作形成的神经病理学机制。结果：Southwestern印迹的实验显示海马结构内有两种调控GFAP基因表达的序列特异的DNA结合蛋白,分子量分别为39kDa和35.5kDa;KA后1d,两种调控蛋白的表达即开始增加,5－7d时表达显著增加,3周时表达最多,3个月时表达仍很高。结论：KA通过上调调控GFAP基因表达的转录因子,使海马GFAP过量表达,提示该转录调控因子很可能参与一次KA后癫痫反复发作的形成。     

取食经历对美洲斑潜蝇雌成虫寿命及生殖力的影响

在实验室条件下 ,研究了取食经历对美洲斑潜蝇雌Liriomyzasativae成虫寿命和生殖力的影响。结果表明 ,幼虫期在黄瓜取食而成虫期在四季豆上取食时 ,其雌成虫寿命、总产卵量和日平均产卵量均明显小于幼虫期在长豇豆上取食而成虫期在四季豆上取食时 (P <0 0 1 ) ;当幼虫期同在长豇豆上取食时 ,成虫在黄瓜上取食时的雌成虫寿命、总产卵量和日平均产卵量均明显小于成虫在四季豆取食时 (P<0 0 5或P <0 0 1 )。这说明美洲斑潜蝇幼虫和成虫取食经历对其成虫寿命和生殖力均有显著的影响     

粉防己碱拮抗豚鼠庆大霉素急性肾损伤的实验研究

目的 :探讨粉防己碱 (Tet)在庆大霉素 (GM)急性肾损伤中的拮抗作用。方法 :将豚鼠分为对照组、Tet组、GM组和Tet+GM组 ,于第 1 1d留取尿标本和肾组织 ,测定尿中NAG活性 ,观察肾组织学改变 ,用免疫组化技术测定Actin和TGF β1 在肾脏的表达。结果 :光镜和电镜显示Tet+GM组肾脏病理变化比GM组轻 ,细胞凋亡也明显少于GM组。Tet+GM组NAG活性比GM组低 (P <0 .0 1 ) ,而TGF β1 和Actin的表达在Tet +GM组高于GM组(P <0 .0 1 )。结论 :Tet能明显降低GM所致的急性肾损伤时NAG活性 ,减少Actin的破坏和细胞凋亡 ,诱导内源性TGF β1 蛋白表达水平上调 ,对GM急性肾损伤有拮抗作用     

17个新的C2H2型锌指基因片段的分离与克隆

按照Ｃ２Ｈ２型锌指基因保守结构域的ＤＮＡ序列设计一对简并引物,以人基因组ＤＮＡ为模板进行ＰＣＲ同源扩增,将由此获得的锌指基因片段为探针,从人胎肾、骨骼肌、骨骼组织的ｃＤＮＡ分子库中筛选到２２个Ｃ２Ｈ２型锌指蛋白ｃＤＮＡ片段,经国际ＮＣＢＩ数据库查询检索,其中１７个为新的锌指基因片段。对从胎肾ｃＤＮＡ分子库中分离到的Ｋ３－４和Ｋ５－１２克隆进行了表达谱分析,发现Ｋ３－４在肾脏中的表达量明显高于其他几     

高通量流式荧光微球悬液芯片检测乙肝病毒基因分型

目的:建立HBV基因分型高通量液相芯片检测技术,并探讨其应用价值.方法:对GenBank中收录的明确分型的HBV基因序列进行分析,选择preS2-S区设计引物和A、B、C和D型特异性探针.与荧光编码微球偶联的特异型探针与一条引物生物素标记的PCR产物直接杂交反应,然后结合亲和素标记的藻红蛋白,用流式检测仪(Bio-Plex 200)检测荧光信号.检测182份阳性乙肝患者血清DNA,其中35份样品检测结果与测序法比较.用B、C型质粒DNA倍比稀释及混合样品检测灵敏度来评估该方法.结果:建立了HBV基因分型的快速高通量液相芯片检测方法.182份患者血清检测结果为:B型占24.2％ (44/182),C型占71.4％(130/182),D型为6.6 ％(12/182),BC混合型4.4％(8/182).其中35份样本与测序法比较,除3份混合型测序法未检出外,其它32例结果均相同本方法的灵敏度检测下线为1×103 copies/mL.结论:应用悬液芯片技术进行乙肝病毒的基因分型分析,具有较好的特异性和较高的灵敏度,并有简便、灵活和高通量等优势.该检测系统不仅在科研中有广泛的前景,也有望成为临床推广的多重分子诊断和基因分型的新方法.     

A comprehensive gene network for fine tuning floral development in poplar

Herbaceous model species, especially Arabidopsis has provided a wealth of information about the genes involved in floral induction and development of inflorescences and flowers. While the genus Populus is an important model system for the molecular biology of woody plant. These two genuses differ in many ways. This study was designed to improve understanding of flower development in poplar at a system level, as its regulatory pathway to a large extent remains poorly known, owing to the presently limited mutant pool. To address this issue, a poplar GeneChip was employed to detect genes expressed during the whole floral developmental process. Using the expressed floral genes, a systematic gene network was constructed with the aid of functional association with Arabidopsis. The results suggested that autonomous, gibberellin, vernalization, photoperiod, ethylene, brassinosteroid, stress-induced and floral suppression pathways are involved in poplar flowering. Modularity analysis revealed several pathways in common with Arabidopsis, such as autonomous, gibberellin, vernalization and photoperiod pathways. In addition, brassinosteroid, stress-induced and floral suppression pathways were implicated as additional novel pathways. Notably, a difference in vernalization between Arabidopsis and poplar was revealed. Autonomous, gibberellin, vernalization, photoperiod, ethylene, brassinosteroid, stress-induced and floral suppression pathways integrated into a systematic gene network in floral development of poplar. Compared to Arabidopsis, brassinosteroid, stress-induced and floral suppression pathways are additional in poplar, and FLC is absent in vernalization pathway in poplar. Preliminary conclusions drawn here provide a basis for both identification of key genes and elucidation of molecular mechanisms involved in poplar floral development.     

聚多曲霉菌原生质体和液泡的制备及优化

原生质体的大量制备是研究原生质体转化、诱变、融合等技术的关键,液泡的制备对研究液泡中分解、转运有机物的特性具有重要意义,但目前分离技术还不够成熟.本研究从聚多曲霉菌菌丝中分离原生质体和液泡并对分离条件进行优化,以聚多曲霉菌DJ515-2菌丝为材料,探索不同因素对原生质体和液泡制备分离效果的影响.结果表明,聚多曲霉菌DJ515-2在菌龄42 h,以3％纤维素酶、1％蜗牛酶和3％的溶壁酶组成复合酶液,25℃下酶解4 h,原生质体达到最大产量,为5.167×105个/mL.同时,在此基础上裂解液泡的最优条件为pH7.5、1.0mol/L KCl、0.020％Triton X-10,其产量达2.63×105个/mL,产率为原生质体的50.8％,相比采用多元碱化合物诱导真菌原生质体裂解释放液泡的产率增加了 40％～45％.本研究为真菌和植物的各种原生质体技术及基于亚细胞层面的研究提供了材料基础.     

环境无机汞对泥鳅视网膜S100表达影响

用含低浓度Hg2 的水饲养泥鳅(Misgurnus anguillicaudatus),研究Hg2 污染对视网膜中S100免疫反应阳性结构数量及分布的影响。用免疫组织化学ABC法标记S100免疫阳性(S100-IR)细胞,显微镜下观察S100免疫反应阳性细胞并计数。结果显示,处理组S100首先在神经节细胞层(GCL)、神经纤维层(NFL)表达,然后逐渐在其他各层表达。与对照组相比,处理组S100免疫反应阳性细胞数显著增多,且该变化与环境中无机汞处理时间成正相关;阳性细胞胞体明显膨胀,突起稠密粗大,S100阳性反应强。研究提示,Hg2 的神经毒害作用导致泥鳅视网膜中S100-IR细胞数的增多。推测Hg2 污染可能对视网膜有伤害性影响,而神经胶质细胞在视网膜修复过程中起了重要作用。