Disentangling the relative importance of climate,size and competition on tree growth in Iberian forests: implications for forest management under global change

Most large‐scale multispecies studies of tree growth have been conducted in tropical and cool temperate forests, whereas Mediterranean water‐limited ecosystems have received much less attention. This limits our understanding of how growth of coexisting tree species varies along environmental gradients in these forests, and the implications for species interactions and community assembly under current and future climatic conditions. Here, we quantify the absolute effect and relative importance of climate, tree size and competition as determinants of tree growth patterns in Iberian forests, and explore interspecific differences in the two components of competitive ability (competitive response and effect) along climatic and size gradients. Spatially explicit neighborhood models were developed to predict tree growth for the 15 most abundant Iberian tree species using permanent‐plot data from the Spanish Second and Third National Forest Inventory (IFN). Our neighborhood analyses showed a climatic and size effect on tree growth, but also revealed that competition from neighbors has a comparatively much larger impact on growth in Iberian forests. Moreover, the sensitivity to competition (i.e. competitive response) of target trees varied markedly along climatic gradients causing significant rank reversals in species performance, particularly under xeric conditions. We also found compelling evidence for strong species‐specific competitive effects in these forests. Altogether, these results constitute critical new information which not only furthers our understanding of important theoretical questions about the assembly of Mediterranean forests, but will also be of help in developing new guidelines for adapting forests in this climatic boundary to global change. If we consider the climatic gradients of this study as a surrogate for future climatic conditions, then we should expect absolute growth rates to decrease and sensitivity to competition to increase in most forests of the Iberian Peninsula (in all but the northern Atlantic forests), making these management considerations even more important in the future.     

利用cDNA微阵列-CGH筛选支气管上皮细胞恶性转化中的扩增基因

目的:基因组不稳定是导致肺癌发生与发展的重要分子机理之一。本研究旨在筛选支气管上皮细胞恶性转化过程中拷贝数扩增的基因。方法:利用业已建立的支气管上皮细胞体外恶性转化模型,通过cDNA微阵列-CGH技术对支气管上皮来源的永生化细胞和癌变细胞的基因拷贝数进行了检测,并对部分结果进行了实时PCR验证。结果:永生化BEP2D细胞染色体中的某些区域存在不同程度的扩增,包括5q31.3、9q32-33.1、14q22.2-23.1、19p13.12-13.13、20q13.12-13.31;恶性转化BERP35T2细胞染色体中的扩增区域集中在1p12-13.1、5q33.1、5q31.3、9q32、19p13.12-13.13;5q31.3、9q32、19q13.12-13.13是以上2种细胞系中的共同扩增区域。共检测到201个基因的拷贝数发生扩增,其中PCNA、TP53及GADD45A基因的异常扩增已经实时PCR进一步验证。结论:在支气管上皮细胞恶性转化过程中,病毒与低剂量辐射的双重作用使得某些重要基因的拷贝数发生扩增,因基因剂量增加而导致某些癌基因高表达可能是细胞恶性转化的重要机制之一。     

濒危植物南方红豆杉濒危原因分析

南方红豆杉是我国第三纪孑遗特有树种,为国家1级濒危保护植物,主要分布于在长江流域、南岭山脉以及广东、广西、江西、河南、陕西、甘肃、台湾和山西等省（区）的山地。南方红豆杉分布区的生态环境特征是：热量充足,温暖潮湿。南方红豆杉濒危的主要原因有：（1）种子产生量少,萌发率和幼苗成活率较低（2）种群缺乏较强的竞争力,（3）地理分布的局限性,（4）对生境要求的特殊性和（5）人为破坏严重。此外,针对南方红豆杉濒危现状和原因,还提出了科学保护和可持续利用的对策。     

mTOR信号通路及其与阿尔茨海默病的关系

哺乳动物雷帕霉素靶蛋白mTOR是一个进化上十分保守的蛋白激酶,属于PIKK超家族。在细胞内mTOR存在两种功能不同的复合体mTORC1和mTORC2。mTOR主要通过接受上游信号分子Rheb、TSC1/TSC2的调控来整合细胞内外信号,其下游效应器是4E-BP和p70S6K,通过影响特定mRNA的翻译调节细胞的生长和增殖。在神经系统方面,神经元的发育、突触可塑性的调节、学习和记忆的形成都依赖于适当的mTOR通路的活化。新近的研究显示,神经退行性疾病阿尔茨海默病患者表现mTOR通路的异常,在双转基因鼠中,APP和PS1表达与mTOR/P70S6K下调关联,并影响精神状态评分。mTOR信号通路生理功能和调节机制的研究对了解AD的发病机理和寻找药物靶点具有重要意义。     

兰属腋花组若干种类的研究

对新种丽花兰Cymbidium concinnum Z. J. Liu &; S. C. Chen和新变种龙州兰C. eburneum var. longzhouense Z. J. Liu &; S. C. Chen进行了描述和绘图; 丽花兰与大雪兰C. mastersii Griff. ex Lindl.有亲缘关系, 区别点在于新种叶片先端不分裂, 花序具18-22朵花, 唇瓣中裂片上有一个V型的紫红色斑块; 龙州兰(变种)与独占春(原变种)的主要区别在于唇瓣中裂片上和侧裂片顶部有较密的紫红色斑。对象牙白C. maguanense的分类问题进行了讨论, 并为其指定了新模式; 还为腋花组sect. Eburnea国产种类提供一个检索表。     

Urinary biomarkers of 1,3-butadiene in environmental settings using liquid chromatography isotope dilution tandem mass spectrometry

Although, 1,3-butadiene is a known human carcinogen emitted from mobile sources, little is known about traffic-related human exposure to this toxicant. This pilot study was designed to characterize traffic-related environmental exposure to 1,3-butadiene and evaluate its urinary mercapturic acids as biomarkers of exposure in these settings. Personal air samples and multiple urine samples were collected on two separate occasions from three groups of individuals that differed by spatial proximity as well as intensity of traffic: (i) toll collectors, (ii) urban-weekday and (iii) suburban-weekend group. Air samples were analyzed using thermal desorption followed by GC/MS and urine samples were analyzed using isotope dilution liquid chromatography tandem mass spectrometry (ID-LC-MS/MS) for two mercapturic acids of 1,3-butadiene: monohydroxy-3-butenyl mercapturic acid (MHBMA) and 1,2-dihydroxybutyl mercapturic acid (DHBMA). Exposure differed between groups (p<0.05) with median values of 2.38, 1.62 and 0.88 microg/m(3) for toll collectors, the urban-weekday group and the suburban-weekend group, respectively. A refined ID-LC-MS/MS method enabled detection of MHBMA, previously detected only in occupational settings, with high frequency. MHBMA and DHBMA were detected in 95 and 100% of urine samples at levels (mean+/-S.D.) of 9.7+/-9.5, 6.0+/-4.3 and 6.8+/-2.6 ng/mL for MHBMA and 378+/-196, 258+/-133 and 306+/-242 ng/mL for DHBMA for the three different groups, respectively. Mean biomarker levels were higher among the toll collectors compared to the other two groups, however, the differences were not statistically significant (p>0.05). This study is the first to evaluate 1,3-butadiene biomarkers for subtle differences in environmental exposures. However, additional research will be required to ascertain whether the lack of statistical association observed here is real or attributable to unexpectedly small differences in exposure between groups (<1 microg/m(3)), non-specificity of the biomarker at low exposure, and/or small sample size.     

重组泛素连接酶SH2-U—box／RING的构建与表达

目的构建重组泛素连接酶SH2-U—box、SH2-RING,并克隆进入pFlag—CMV4真核表达载体,为研究靶向降解慢性粒细胞白血病（chronic myelocytic leukemia,CML）患者瘤细胞中过度活化的BCR／ABL,抑制肿瘤细胞的生长提供基础。方法设计引物,扩增接头分子Grb2的SH2结构域以及E3泛素连接酶CHIP的U—box、Cb1的RING结构域,通过重组PCR,将SH2分别与U—box、RING进行融合,融合片段双酶切之后插入真核表达载体pFlag—CMV4,经过酶切鉴定及测序后,转染HEK293T细胞,Western印迹验证重组质粒的表达。结果PCR结果提示SH2-U—box条带大小888bp,SH2一RING大小为633bp,重组质粒酶切鉴定和测序结果均正确,转染后可见融合蛋白的表达。结论成功构建真核重组表达载体pFlag—CMV4-SH2-U—box和pFlag—CMV4-SH2-RING,转染HEK293T细胞后能够正确表达,为后续研究奠定了基础。     

丹参壮苗指数及其模拟模型

通过对丹参幼苗各数量性状及比值与幼苗质量的相关性分析,确定有代表性的可以反映幼苗质量的数量性状指标,同时结合关联度分析确定适于丹参幼苗的壮苗指数,并依据丹参壮苗指数与气温、光辐射和空气湿度的关系,建立了基于环境影响因子积的丹参幼苗壮苗指数模拟模型,再利用不同播期和试验地试验资料对模型进行检验.结果表明:根粗、茎粗、地上部干质量、根干质量和全株干质量等数量性状与其他性状相关性显著,而且性状稳定,容易测量,可以作为衡量壮苗的指标性状.丹参幼苗的壮苗指数=(茎粗/根粗+根干质量/地上部干质量)×全株干质量.其中,全株干质量、根干质量、地上部干质量和茎粗与壮苗指数的关联度较大,该壮苗指数可以较好地反映丹参幼苗质量.壮苗指数模型对丹参壮苗指数的预测值与实测值之间基于1∶1直线的R2=0.95,RMSE=0.15,模型能较为准确地反映实际壮苗指数与环境因子之间的定量关系.     

革兰阴性菌引起的血培养阳性标本直接细菌鉴定和药敏的应用

目的 评估血培养阳性标本直接细菌鉴定和药敏可行性.方法 将血培养瓶放入Bact/Alert 3D 60血培养系统进行培养筛选.选取78份含革兰阴性杆菌的阳性血培养瓶进行试验.抽取培养液,用BD真空分离管离心血细胞.在收集到足量菌液后,用VITEK-32革兰阴性菌鉴定药敏卡做直接鉴定药敏试验.用标准方法及亚培养后的鉴定药敏试验对直接鉴定药敏试验进行评估.结果 VITEK-32直接鉴定试验,78株中的74株(94.9％)准确鉴定,直接药敏试验标准符合率95.6％.KB法血标本直接药敏试验标准符合率96.2％,但微小错误率高于VITEK-32直接药敏法.结论 Bact/Alert血培养阳性标本直接VITEK-32细菌鉴定和药敏对革兰阴性菌是切实可行的,可大幅度缩短时间,为临床及时修正用药提供依据,具有较高的应用价值.