Heterologous signals allow efficient targeting of a nuclear-encoded fusion protein to plastids and endoplasmic reticulum in diverse plant species

Approximately 30% of plant nuclear genes appear to encode proteins targeted to the plastids or endoplasmic reticulum (ER). The signals that direct proteins into these compartments are diverse in sequence, but, on the basis of a limited number of tests in heterologous systems, they appear to be functionally conserved across species. To further test the generality of this conclusion, we tested the ability of two plastid transit peptides and an ER signal peptide to target green fluorescent protein (GFP) in 12 crops, including three monocots (barley, sugarcane, wheat) and nine dicots ( Arabidopsis , broccoli, cabbage, carrot, cauliflower, lettuce, radish, tobacco, turnip). In all species, transient assays following microprojectile bombardment or vacuum infiltration using Agrobacterium showed that the plastid transit peptides from tomato DCL (defective chloroplast and leaves) and tobacco RbcS [ribulose bisphosphate carboxylase (Rubisco) small subunit] genes were effective in targeting GFP to the leaf plastids. GFP engineered as a fusion to the N-terminal ER signal peptide from Arabidopsis basic chitinase and a C-terminal HDEL signal for protein retention in the ER was accumulated in the ER of all species. The results in tobacco were confirmed in stably transformed cells. These signal sequences should be useful to direct proteins to the plastid stroma or ER lumen in diverse plant species of biotechnological interest for the accumulation of particular recombinant proteins or for the modification of particular metabolic streams.     

女性冠心病患者的危险因素分析及与冠脉病变严重程度的关系

目的:了解女性冠心病患者的危险因素及与冠脉病变严重程度的关系。方法:随机选取本院2012年至2014年心血管科住院治疗的疑似冠心病女性患者150例,经冠脉造影确诊冠心病患者105例,非冠心病患者45例。对患者的临床资料和冠脉病变严重程度进行单因素和多因素分析。结果:冠心病患者高血压与糖尿病百分比、甘油三酯(TG)、总胆固醇(TC)、低密度脂蛋白(LDL-C)及纤维蛋白原水平均高于非冠心病患者,而高密度脂蛋白(HDL-C)和血红蛋白水平均低于非冠心病患者(P0.05);年龄、高血压与糖尿病百分比、血脂上升百分比(高TC、高TG、低HDL-C、高LDL-C)、高尿酸百分比和纤维蛋白原水平均随冠状动脉病变支数及Gensini积分的增加而增加(P0.05);多因素分析发现女性冠心病的影响因素分别为高LDL-C、糖尿病、低HDL-C、TG和高血压,其中高LDL-C的影响最为显著(P0.05)。结论:高血压、糖尿病史、血脂水平为女性冠心病的影响因素,其中高LDL-C的影响最显著,各影响因素均与冠脉病变程度紧密相关。     

宫颈特殊染色技术对子宫颈癌及宫颈上皮内瘤变初筛的临床研究

目的:探讨宫颈特殊染色技术筛查方法对宫颈癌及癌前病变的筛查意义。方法:本研究通过对1963例就诊我院妇科门诊的患者进行宫颈特殊染色检查(FRD),以组织病理学检查结果为标准,分析FRD宫颈特殊染色的临床意义。结果:1963例患者行宫颈特殊染色检查及对初筛阳性患者行阴道镜下活检,根据活检病理结果进行分析,CINI阳性率80.77%℅,CINII81.25%,CINIII100%℅,侵润癌100%,总阳性率90.50%。结论:利用亚甲蓝显色和醋酸白化反应双重定位及指示,不仅可提高宫颈癌及癌前病变的检出率,而且操作简便,判读容易,结果快速,成本低廉。     

Hotspot Scenario Analysis

Increasingly, organizations are working to reduce the environmental footprint of their supply chains. The use of environmentally preferable purchasing criteria is one strategy organizations use to address this goal. However, evaluating the environmental performance of these criteria (e.g., recycled content, biodegradable, renewable, and so on) has remained elusive. Life cycle assessment (LCA) can measure the impact reduction potential of sourcing strategies. However, full process‐based LCAs are time‐consuming and costly across multiple criteria of thousands of products and inputs purchased in an organizational setting. A streamlined “hotspot” methodology is presented using a combination of environmentally extended economic input‐output (EEIO) approaches and extant literature to identify hotspots in which to constrain a parameterized process‐based LCA. A case study of breakfast cereal manufacturing is developed to (1) assess the efficiencies associated with the hotspotting approach and (2) demonstrate its applicability in generating comparable decision signals of environmentally preferable sourcing criteria for procurement and supply‐chain managers along the dimensions of global warming potential and water use.     

Temperature and snowfall trigger alpine vegetation green‐up on the world's roof

Rapid temperature increase and its impacts on alpine ecosystems in the Qinghai–Tibetan Plateau, the world's highest and largest plateau, are a matter of global concern. Satellite observations have revealed distinctly different trend changes and contradicting temperature responses of vegetation green‐up dates, leading to broad debate about the Plateau's spring phenology and its climatic attribution. Large uncertainties in remote‐sensing estimates of phenology significantly limit efforts to predict the impacts of climate change on vegetation growth and carbon balance in the Qinghai–Tibetan Plateau, which are further exacerbated by a lack of detailed ground observation calibration. Here, we revealed the spatiotemporal variations and climate drivers of ground‐based herbaceous plant green‐up dates using 72 green‐up datasets for 22 herbaceous plant species at 23 phenological stations, and corresponding daily mean air temperature and daily precipitation data from 19 climate stations across eastern and southern parts of the Qinghai–Tibetan Plateau from 1981 to 2011. Results show that neither the continuously advancing trend from 1982 to 2011, nor a turning point in the mid to late 1990s as reported by remote‐sensing studies can be verified by most of the green‐up time series, and no robust evidence for a warmer winter‐induced later green‐up dates can be detected. Thus, chilling requirements may not be an important driver influencing green‐up responses to spring warming. Moreover, temperature‐only control of green‐up dates appears mainly at stations with relatively scarce preseason snowfall and lower elevation, while coupled temperature and precipitation controls of green‐up dates occur mostly at stations with relatively abundant preseason snowfall and higher elevation. The diversified interactions between snowfall and temperature during late winter to early spring likely determine the spatiotemporal variations of green‐up dates. Therefore, prediction of vegetation growth and carbon balance responses to global climate change on the world's roof should integrate both temperature and snowfall variations.     

Overexpressed GRP78 affects EMT and cell-matrix adhesion via autocrine TGF-β/Smad2/3 signaling

Glucose-regulated protein of 78 kD (GRP78) is a multifunctional protein belonging to the heat shock protein 70 family. Overexpression of GRP78 triggered by environmental and physiological stresses is positively correlated with the occurrence and progression of various tumors, but the molecular mechanisms have not been well established. The present study indicated that overexpression of GRP78 in colon cancer cells could promote cell-matrix adhesion through the upregulation of fibronectin, integrin-β1 and phosphorylated FAK. Meanwhile, it resulted in a visible epithelial–mesenchymal transition in DLD1 cells, and the Snail-2 played the key role during the process. More importantly, the data indicated that GRP78 overexpression facilitated the expression and secretion of TGF-β1, which further activated the downstream Smad2/3 signaling module to effectuate the cell-matrix adhesion and epithelial–mesenchymal transition. Taken together, this study provides a novel molecular mechanism involving in the effects of GRP78 on colon cancer metastasis.     

Field trapping of the flathead oak borer Coroebus undatus (Coleoptera: Buprestidae) with different traps and volatile lures

The flathead oak borer Coroebus undatus F. (Coleoptera: Buprestidae) is one of the primary pests of cork oak Quercus suber L. in the Mediterranean region causing great economic losses to the cork industry. Very little is known about its biology and behavior and, so far, no control measures have been established. We present the results of a pilot study aimed to develop an efficient trapping method for monitoring this harmful pest. In a 3‐year field study, purple‐colored prism traps baited with a mixture of green leaf volatiles (GLVs) from the host have been shown the most effective combination to catch C. undatus adults (solely females) compared to other trap and lure types tested. Wavelength and reflectance measurements revealed that purple traps exhibit reflectance peak values similar to those found in the abdominal and elytral cuticle of both sexes, suggesting the involvement of visual cues for mate location in this species. The data presented are the first to demonstrate captures of adults of the genus Coroebus by an attractant‐based trapping method.     

从绿色荧光蛋白的发现谈如何提出新颖的科研问题

为了使研究生在获得专业知识的同时,还可以依据文献提出新的科研问题,并设计实验方案来解决提出的问题,我们以绿色荧光蛋白为案例教学,谈谈在其发现过程中是如何提出问题以及提出问题所用的思维方式。启发研究生运用求异和置换的思维方式来提出新颖的科研问题,并设计实验来回答提出的问题,从而为研究生完成学术论文奠定良好的基础。     

全球气候变化与粮食安全——2012年Planet Under Pressure国际会议述评

"Planet Under Pressure 2012——NEW KNOWLEDGE TOWARDS SOLUTIONS"会议于2012年3月26日至3月29日在英国首都伦敦召开,来自全球100多个国家和地区的科学家共同讨论减轻地球压力的新方法,为6月将要举办的Rio+20可持续发展大会提供科学的理念和建议。会上,粮食安全方面的相关研究主要探讨了气候变化、城市化、全球化、人口增长、疾病、食物消费结构、经济发展水平等因素对粮食安全的影响,并讨论了全球气候变化条件下实现粮食安全的可能的途径,诸如扩大高产农用地面积、发展以农户为基本单位的农业、推行基因农业、提高农业信息化水平、制定合理的政策等。会议表现出三大特点:(1)多尺度、多领域信息的充分交流;(2)提出了绿色经济、绿色发展等新的科学理念;(3)强调科学和政策的结合。四个方面的启示:(1)加强各学科的结合,不断开拓新的研究领域,提出新的研究思路;(2)全面考虑,将理论和实际有效结合;(3)增强政府与科学家的沟通与交流;(4)拓展国际视野,加强全球方面的研究,提高参与全球活动的主动性和积极性。     

不同管理方式下橡胶林土壤氮动态特征

对西双版纳割胶、未割胶条件下橡胶林种植带土壤及其保护带土壤氮素动态变化特征进行了研究,并比较了不同保护带种植方式(距瓣豆绿肥覆盖与野生杂草覆盖)对土壤氮素动态的影响。结果表明,橡胶林种植带土壤全氮、碱解氮和硝态氮含量低于保护带。橡胶林土壤全氮、碱解氮、铵态氮、硝态氮均呈现明显的动态变化,种植距瓣豆绿肥覆盖与野生杂草生长覆盖的橡胶林土壤氮变化趋势一致。土壤全氮随时间逐渐下降,碱解氮含量先升后降,铵态氮和硝态氮含量变化幅度较大。橡胶林土壤全氮和碱解氮含量呈现表层(0～20cm)>中层(20～40cm)>底层(40～60cm)的趋势,且未割胶处理全氮和碱解氮含量>割胶处理,而保护带为距瓣豆绿肥覆盖的割胶橡胶林>杂草生长覆盖的橡胶林。距瓣豆绿肥覆盖的保护带土壤硝态氮含量高于杂草生长覆盖。碱解氮与铵态氮含量呈显著的负相关、与硝态氮呈显著正相关。割胶橡胶林土壤氮养分含量最低。橡胶林土壤种植豆科距瓣豆绿肥能够改善土壤氮素肥力。