Effects of biodiversity,stand factors and functional identity on biomass and productivity during the restoration of subtropical forests in Central China

恢复梯度上华中亚热带森林生物多样性、林分因子及功能特性对生物量、生产力的影响 草地群落上进行的控制实验大都发现生物多样性对生态系统功能有显著促进作用。然而,在天然林中,多样性与林分因子、群落功能特性的相对作用大小仍存在争议。本文在森林恢复梯度上,研究这3类因素对生物量和生产力的相对影响。我们在湖北神农架设置了处于不同恢复阶段的24块(600 m²)亚热 带森林样地,计算了林分生物量和生产力。选择5个关键的植物功能性状,并计算了群落的功能多样性(功能丰富度、功能均匀度和功能离散度)和性状的加权平均值(CWM)。使用一般线性模型(GLMs)、变异分离等方法探究林分因子(密度、林龄、群落最大树高等)、功能特性、物种和功能多样性对生物量和生产力的相对重要性。研究结果表明,随着森林恢复,林分生物量和生产力显著增加,群落物种丰富度显著增加,而功能离散度显著降低。变异分离结果表明,多样性对生物量和生产力的单独效应不显著,但可能通过与林分因子和功能特性的协同效应来影响生物量和生产力。总体而言,我们发现林分因子对亚热带森林生物量和生产力的影响最大,功能特性显著影响生产力,但不影响生物量。这些结果说明,在森林经营中,调整林分结构和群落物种特性是提高森林碳储量和固碳潜力的有效途径。     

肿瘤转移的分子机制及靶向干预研究新进展

肿瘤转移是一个多阶段的恶性进展过程,涉及肿瘤细胞从原发部位逃逸,侵入脉管系统并在其中存活,随循环系统到达远处靶器官并穿出脉管系统播散定植,最终克隆性生长形成转移瘤。转移过程的每一阶段与肿瘤细胞本身遗传和表观遗传改变以及微环境中诸多因素的综合调控密切相关。本综述概要介绍了恶性肿瘤转移多步骤过程中所涉的分子调控机制以及肿瘤转移靶向干预新措施等方面的研究进展;同时,就未来肿瘤转移研究相关的新技术和新方向作一简单的展望。     

适合免疫治疗的大鼠抗肾小球基底膜肾炎模型的建立

以线性表位肽P14（a3_127-148）作为抗原建立适合免疫治疗的抗肾小球基底膜（anti-glomerular basement membrane,GBM）病大鼠模型。采用大鼠后脚垫三点注射P14（a3_127-148）与弗氏佐剂乳化物的方法进行单次免疫,免疫前后每周采集24 h尿样和血样,所有大鼠在免疫后7 w处死。大鼠免疫后,肾炎模型组在各时间点的24 h尿蛋白、尿蛋白肌酐比值（albumin/urine creatinine ratio,ACR）、血肌酐及血尿素氮均明显高于对照组（P<0.05）;循环抗P14（a3_127-148）IgG抗体水平明显高于对照组(P<0.001);PAS染色可见节段性纤维素样坏死,富于细胞型新月体;免疫组化染色可见肾小球有明显的中性粒细胞和巨噬细胞浸润;免疫荧光检测可见IgG沿GBM呈强线性沉积;电镜观察到GBM的断裂和收缩;而对照组均未见改变。HE染色在所有大鼠中均未观察到肺部病变。使用P14（a3_127-148）线性肽免疫WKY大鼠成功建立了大鼠抗GBM病模型,有助于开发更为特异的免疫疗法。     

光信号转导因子HY5调控拟南芥分枝的功能研究

光是影响植物分枝的重要外在环境因素,但光信号因子HY5（ELONGATED HYPOCOTYL5）是否调控植物分枝目前尚不清楚。创制了HY5转基因超表达植株,并获得商业化T-DNA插入突变体纯合植株。通过比较野生型（WT）、超表达植株（HY5-OE）、突变体（hy5-215）的分枝数目发现,与野生型相比,超表达植株分枝数目显著增加,而突变体分枝数目则显著减少。进一步比较这些遗传材料的拟南芥植株分枝的负调控关键因子BRC1（BRANCHED1）转录本水平差异,发现与野生型相比,超表达植株中BRC1转录本显著下调、突变体中显著上调。研究结果表明,HY5通过抑制拟南芥分枝关键负调控因子BRC1的转录水平,进而促进拟南芥的分枝。研究结果为阐明HY5调控分枝的生物学功能提供了一定的理论依据。     

纳木措湖沿岸表层水细菌群落特征及影响因素

为了探究夏季纳木措湖沿岸表层水体细菌群落特征,为以后纳木措湖细菌的研究打下基础,围绕纳木措湖一周选取采样点19个。现场采集水样,进行理化因子测定,运用高通量测序技术获取上述样点的16S rDNA数据,根据多样性指数和丰富度指数计算比较各样点的细菌群落多样性和丰富度,根据各样点细菌群落在门和属水平的分布来研究纳木措各样点细菌分布差异,基于Spearman相关性系数来衡量理化因子与α-多样性指数的相关性,采用冗余分析（redundancy analysis, RDA）探究理化因子与细菌群落分布之间的关系。在纳木措水体中共获得细菌4 137个OTU（operational taxonomic units）,属于87门204纲498目645科1 185属。门水平优势菌群为变形菌门（Proteobacteria,39.61%）、拟杆菌门（Bacteroidetes,13.41%）和厚壁菌门（Firmicutes,12.61%）,其中,变形菌门以γ-变形菌为优势菌群,其次为β-变形菌和α-变形菌。属水平有71.67%的未知细菌菌属。纳木措Shannon多样性指数显示,纳木措细菌种类比较丰富。Spearman相关性系数显示,水体细菌α-多样性指数与环境因子之间没有相关性。RDA分析表明,影响纳木措水体细菌群落结构的主要理化因子为温度（P=0.002,F=5.7）。纳木措沿岸表层水体细菌群落分布差异较为明显,细菌群落比较丰富,有许多未知菌种需进一步鉴定,有广阔的研究前景。     

Two New Sesquiterpenoid Glucosides from the Aerial Parts of Saussurea involucrate

Two new sesqulterpenoid glucosides, namely α-hydroxycostic acid 6-β-D-glucopyranoside （compound 1） and 11 βH-11,13-dlhydrodehydrocostuslactone 8α-O-（6＇-acetyl）-β-D-glucopyranoside （compound 2）, along with 11 known sesqulterpenoids （compounds 3-13） were isolated from the aerial parts of Saussurea involucrate （Kar. et Kir.） Sch.- BIp. The structures of the new sesquiterpenoid glucosides were established by one- and two-dimensional nuclear magnetic resonance and mass spectrometry analysis.     

Inhibition of tumor growth in mice by endostatin derived from abdominal transplanted encapsulated cells

Endostatin,a C-terminal fragment of collagen 18a,inhibits the growth of established tumorsand metastases in vivo by inhibiting angiogenesis.However,the purification procedures required for large-scale production and the attendant cost of these processes,together with the low effectiveness in clinicaltests,suggest that alternative delivery methods might be required for efficient therapeutic use of endostatin.In the present study,we transfected Chinese hamster ovary(CHO)cells with a human endostatin geneexpression vector and encapsulated the CHO cells in alginate-poly-L-lysine microcapsules.The release ofbiologically active endostatin was confirmed using the chicken chorioallantoic membrane assay.The encap-sulated endostatin-expressing CHO cells can inhibit the growth of primary tumors in a subcutaneous B 16tumor model when injected into the abdominal cavity of mouse.These results widen the clinical applicationof the microencapsulated cell endostatin delivery system in cancer treatment.     

Novel tumor-associated antigen of hepatocellular carcinoma defined by monoclonal antibody E4-65

A monoclonal antibody, E4-65, produced by immunizing mice with SMMC-7721 cells, a human hepatocellular carcinoma (HCC) cell line, was used to identify and characterize an unreported HCC-associated antigen. Indirect immunofluorescence studies showed that E4-65 antibody reacted with five out of eight HCC cell lines, but not with 10 non-HCC tumor cell lines or a normal liver cell line. Using immunohistochemical examination, E4-65 antigen was detected on the cell membranes and in the cytoplasm of human liver tumor tissues, but was not found in most other tumors, or normal adult or fetal tissues, except for a weakly positive reaction in tissues of the digestive system. Western blot analysis showed that E4-65 antibody bound to a 45 kDa protein in the human HCC cell line and tissue lysates. Enzyme treatment and lectin blotting did not detect the carbohydrate chain in E4-65 antigen. This HCC-associated protein represents a potentially useful target for diagnoses and immunotherapy of human HCC.