转Cry1Ab基因水稻分子特征及其特异性PCR检测方法

转Cry1Ab基因水稻Bt01为一种新型的转基因水稻,文章首先利用Southern blotting验证了外源基因Cry1Ab转入了Bt01中,且为单拷贝,再利用TAIL-PCR方法获得了其插入位点信息,根据获得的Bt01的5′端插入位点序列,设计了相应的定性与定量PCR检测体系的引物及探针,实验结果显示,定性PCR检测体系的最低检测极限(LOD)为10个拷贝,定量PCR检测体系的LOD为5拷贝,最低定量极限(LOQ)为10拷贝。同时为了验证建立的定量PCR体系的准确性,利用该体系检测已知转基因水稻Bt01含量分别为3%和0.5%的样品,定量结果分别为2.7%和0.47%。研究结果表明,该转化体特异性定性与定量检测方法具有高度的特异性和良好的灵敏性,为转基因水稻Bt01的身份识别和检测提供了有效的方法。     

转cry1Ac＋cry2Ab基因棉与转cry1Ac＋剧咯邢基因棉荒地的生存竞争能力

【背景】此研究为“十二五”转基因生物新品种培育国家项目中创建新的转基因棉花品种环境安全评价技术而设。【方法】以转双价双成抗虫基因（cry1Ac＋cry2Ab）棉和转双价抗虫、抗除草剂基因（cry1Ac＋肼强阳）棉为观察品种,非转基因棉赣棉11号为对照品种,在荒地用撒播和3cm深度播种2种方式,于2011年5月一2012年3月对棉花出苗率、株高、生育进程、棉吐絮瓣数、絮瓣脱落率、自生苗等生存竞争能力进行比较,检测、评价其杂草化的风险,并探讨、验证检测技术的可行性。【结果】在荒地条件下,以2种方式播种的转cry1Ac＋cry2Ab基因棉和转cry1Ac＋EP5P5基因棉与非转基因棉相比,上述各项指标的竞争能力总体上未表现显著优势。【结论与意义】转cry1Ac＋cry2Ab基因棉和转cry1Ac＋EPSPS基因棉在荒地条件下生长无杂草化风险。同时,研究证明,在荒地自然生态条件下,可以采用撒播和3cm深度播种方法检测新的转基因棉花品种在生存竞争能力上的杂草化风险,在测评上有互为参照效应,为定性评价新的转基因棉花品种的杂草化风险提供了保障。     

陕西杨凌地区黑光灯下金龟甲种类组成及优势种群发生动态

2011年5～9月,在陕西省杨凌区西北农林科技大学植物保护学院试验站设置黑光灯,系统诱集金龟甲并鉴定种类,分析金龟甲种群的发生动态。结果表明,陕西杨凌地区黑光灯可诱到金龟甲3科17种,从5月上旬至9月上旬均可发生,以6月下旬至7月中旬为发生盛期;优势种类为铜绿丽金龟、赤绒鳃金龟、华北大黑鳃金龟和暗黑鳃金龟,发生盛期分别为6月下旬至7月下旬、7月下旬至8月上旬、7月上旬和6月下旬至7月下旬。     

An entirely cell-based system to generate single-chain antibodies against cell surface receptors

The generation of recombinant antibodies (Abs) using phage display is a proven method to obtain a large variety of Abs that bind with high affinity to a given antigen. Traditionally, the generation of single-chain Abs depends on the use of recombinant proteins in several stages of the procedure. This can be a problem, especially in the case of cell-surface receptors, because Abs generated and selected against recombinant proteins may not bind the same protein expressed on a cell surface in its native form and because the expression of some receptors as recombinant proteins is problematic. To overcome these difficulties, we developed a strategy to generate single-chain Abs that does not require the use of recombinant protein at any stage of the procedure. In this strategy, stably transfected cells are used for the immunization of mice, measuring Ab responses to immunization, panning the phage library, high-throughput screening of arrayed phage clones, and characterization of recombinant single-chain variable regions. This strategy was used to generate a panel of single-chain Abs specific for the innate immunity receptor Toll-like receptor 2. Once generated, individual single-chain variable regions were subcloned into an expression vector allowing the production of recombinant Abs in insect cells, thus avoiding the contamination of recombinant Abs with microbial products. This cell-based system efficiently generates Abs that bind to native molecules on the cell surface, bypasses the requirement of recombinant protein production, and avoids risks of microbial component contamination.     

Physical properties of palm fruits processed with tools by wild bearded capuchins (Cebus libidinosus)

Habitually, capuchin monkeys access encased hard foods by using their canines and premolars and/or by pounding the food on hard surfaces. Instead, the wild bearded capuchins (Cebus libidinosus) of Boa Vista (Brazil) routinely crack palm fruits with tools. We measured size, weight, structure, and peak-force-at-failure of the four palm fruit species most frequently processed with tools by wild capuchin monkeys living in Boa Vista. Moreover, for each nut species we identify whether peak-force-at-failure was consistently associated with greater weight/volume, endocarp thickness, and structural complexity. The goals of this study were (a) to investigate whether these palm fruits are difficult, or impossible, to access other than with tools and (b) to collect data on the physical properties of palm fruits that are comparable to those available for the nuts cracked open with tools by wild chimpanzees. Results showed that the four nut species differ in terms of peak-force-at-failure and that peak-force-at-failure is positively associated with greater weight (and consequently volume) and apparently with structural complexity (i.e. more kernels and thus more partitions); finally for three out of four nut species shell thickness is also positively associated with greater volume. The finding that the nuts exploited by capuchins with tools have very high resistance values support the idea that tool use is indeed mandatory to crack them open. Finally, the peak-force-at-failure of the piassava nuts is similar to that reported for the very tough panda nuts cracked open by wild chimpanzees; this highlights the ecological importance of tool use for exploiting high resistance foods in this capuchin species.     

An objective, rapid and reproducible method for scoring AFLP peak-height data that minimizes genotyping error

Amplified fragment length polymorphism (AFLP) fingerprint data are now commonly collected using DNA sequencers. AFLP genotypes are still often scored by eye from such data - a time-consuming, error-prone and subjective process. We present a semi-automated method of genotyping sequencer-collected AFLPs at predefined fragment locations (loci) within the fingerprint. Our method uses thresholds of AFLP-polymerase chain reaction-product fluorescence intensity (peak height) in order to: (i) exclude AFLP loci that are likely to contribute high rates of error to data sets, and (ii) determine the AFLP phenotype (fragment presence or absence) at the retained loci. Error rate analysis is an integral part of this process and is used to determine optimal thresholds that minimize genotyping error, while maximizing the numbers of retained loci. We show that application of this method to a large AFLP data set allows genotype calls that are rapid, objective and repeatable, facilitating the extraction of reliable genotype data for molecular ecological studies.     

The effect of storage and active ingredient properties on the drug release profile of poly(ethylene oxide) matrix tablets

Different molecular weight forms of poly(ethylene oxide) can be used successfully in controlled release drug delivery due to their excellent matrix forming properties. Drug release of these materials follows nearly zero order kinetics, and is mainly governed by polymer swelling and erosion and diffusion of drug molecules. Because of its partly amorphous structure, poly(ethylene oxide) undergoes structural changes caused by elevated temperature and relative humidity of the storage medium resulting in an increased drug release. This physical process can be highly influenced by the structure of different drug molecules, such as polymer-binding ability and hydration tendency. These properties of two basic drugs embedded into poly(ethylene oxide) matrices were characterized by molecular modelling and an attempt was made to reveal their effect on the change of drug release stability, a prerequisite of the marketing authorization of dosage forms. The findings suggest that both the hydration properties of the active ingredient and the molecular weight of the polymer influence the effect of physical ageing of poly(ethylene oxide) on the drug release properties of the matrix.     

弄拉典型峰丛岩溶区青冈栎叶片形态特征及对环境的适应

选取广西弄拉典型峰丛洼地生态系统中不同地貌类型的青冈栎 (Cyclobalanopsisglauca)叶片进行形态解剖特征比较分析 ,结果表明 :( 1 )峰丛洼地生态系统中不同地貌青冈栎叶片形态解剖特征差异显著。山顶青冈栎叶片部分表皮结构 (角质膜、表皮毛、表皮细胞、气孔 )趋向旱化。山顶青冈栎下表皮毛比山腰青冈栎的浓密且长。两者叶片的厚度和宽度、上表皮细胞个数、气孔指数、下表皮厚度、栅栏组织厚度、海绵组织厚度存在着显著性差异 ;位于山顶的青冈栎受到水分的胁迫 ,在形态解剖上呈现出中生偏旱的结构。 ( 2 )青冈栎的各种形态解剖指标说明在岩溶区青冈栎的抗旱性主要是通过抵御干旱来适应水分的胁迫 ,并主要取决于减少蒸腾失水和维持水分吸收能力两个方面     

苏云金芽孢杆菌cry2Aa操纵元蛋白对杀虫蛋白晶体形成作用的研究

利用重叠PCR的方法,通过两次PCR扩增,分别获得cry2A10操纵元的orf1、orf1 orf2与cry2Ab5基因的融合片段。融合片段经BamHⅠ和EcoRⅠ双酶切与pHT315连接,分别构建了基因融合片段的原核表达载体pFU(orf1 2Ab)和pFU(orf1 orf2 2Ab),电转化Bt无晶体突变株4Q7后,扫描电镜下可观察到典型的方形晶体,通过SDS-PAGE可检测到60kD大小的蛋白表达带。结果表明,cry2Ab5可在cry2a0的启动子帮助下有效转录和表达,并在orf2产物帮助下形成蛋白晶体。     

Effect of blood volume on plasma volume shift during exercise

To assess the relationship between blood volume (BV) and the reduction in plasma volume (PV) during exercise in individual variations, we measured BV and changes in PV in thirteen male volunteers during treadmill exercise until exhaustion. The lactate threshold (LT), as a predictor of aerobic exercise capacity, was calculated from the exercise intensity at the point of plasma lactate concentration buildup to 4 mmol. The relationship of peak VO₂ with BV indicated a significant positive correlation. The strong positive relation between the shifts in PV and total PV, and resulted in a maintenance of the circulating BV.