一种快速低廉的PCR探针标记方法

【研究目的】探针标记技术是分子生物学和基因工程研究中常用实验技术,需要发展高效、快速、低成本、安全、简捷的DNA探针标记方法;【方法】利用普通的Taq酶进行PCR探针标记,电泳和Southern杂交检测探针标记结果;【结果】电泳检测发现标记产物在电泳时相对非标记的对照表现明显滞后,表明探针标记成功;电泳条带清晰明亮,表明探针标记效率高;Southern杂交条带清晰,说明该方法标记的探针可用于Southern等分子杂交实验;【结论】利用普通的Taq酶进行PCR探针标记,是一种低成本、高效、快速的DNA探针标记方法。     

When goliaths clash: US and EU differences over the labeling of food products derived from genetically modified organisms

There is a fundamental divergence of opinion between the EU and the US over how food products derived from genetically modified organisms should be labeled. This has less to do with safety, as moves towards the international harmonization of safety standards continue apace, and rather more to do with the consumers' right to know about the origins of the food they are consuming. This paper uses a framework drawn from the global public goods (GPG) literature of economics and the work by international relations theorists on formal international organizations (FIO) to explain why there is presently no global consensus on the manner (voluntary or mandatory) in which GM food products should be labeled.     

基于YCbCr颜色空间和Fisher判别分析的棉花图像分割研究

棉花的分割是采棉机器人研究的关键技术。本文分别在HSV、HIS和YCbCr颜色空间下,首先根据棉花的颜色信息与背景颜色信息的差距,对样本图像中的各个对象(棉絮、棉枝、土壤等)分类; 其次根据分类结果分别提取各类在各颜色空间下的样本像素值; 再根据类间离散度最大和类内离散度最小的准则计算出Fisher判别向量和各类的质心; 最后按照像素值离各质心最近的准则进行图像分割。结果表明, 在YCbCr颜色空间下产生的分割噪声最小,选取此颜色空间,采用贴标签的方法自适应去噪。实验仿真表明,本方法可有效避免阳光直射和阴影的干扰,对各种情况都能准确分割,分割准确率达90.44%。     

记录小麦SSR带型的快捷方法

针对小麦SSR带型识别和记录中因带纹繁多和分布复杂而造成带纹判读和记录困难的特点，提出了根据每对SSR引物生成带型间的差别直接对带型进行编号，以有效简化小麦SSR带型的记录方法。该方法避免了由于错误判断引起的实验误差，并可利用每个品种的带型编号，建立品种的DNA指纹以及进行品种基因型比对。     

Regulating sustainability in the coffee sector: A comparative analysis of third-party environmental and social certification initiatives

Certification and labeling initiatives that seek to enhance environmental and social sustainability are growing rapidly. This article analyzes the expansion of these private regulatory efforts in the coffee sector. We compare the five major third-party certifications – the Organic, Fair Trade, Rainforest Alliance, Utz Kapeh, and Shade/Bird Friendly initiatives – outlining and contrasting their governance structures, environmental and social standards, and market positions. We argue that certifications that seek to raise ecological and social expectations are likely to be increasingly challenged by those that seek to simply uphold current standards. The vulnerability of these initiatives to market pressures highlights the need for private regulation to work in tandem with public regulation in enhancing social and environmental sustainability. Laura T. Raynolds is Professor of Sociology and Co-Director of the Center for Fair & Alternative Trade Studies (http://www.colostate.edu/Depts/Sociology/cfats/index.html) at Colorado State University. She has published extensively on organic and Fair Trade certification and globalization and has an edited volume forthcoming, Raynolds, L. T., D. Murray, and J. Wilkinson (eds.) (2007) Fair Trade: The Challenges of Transforming Globalization. London: Routledge Press. Douglas Murray is Professor of Sociology and Co-Director of the Center for Fair & Alternative Trade Studies at Colorado State University. His research and publications focus on global certification and regulatory initiatives, development, environment, and pesticide issues particularly in Latin America. Andrew Heller is PhD Candidate in Sociology and student affiliate of the Center for Fair & Alternative Trade Studies at Colorado State University. He is researching the impacts of certification on Guatemalan small scale coffee producers for his dissertation.     

地高辛3′末端标记检测效率的分析

[目的]为核酸杂交试验提供依据。[方法]利用3个不同长度的核酸探针进行3′末端地高辛标记,并对标记效率进行检测,研究探针的长度和浓度及其在尼龙膜上的固定方法对其信号强度的影响。[结果]聚丙烯酰胺凝胶电泳结果表明地高辛标记的探针比未标记探针滞后,说明标记较为成功。检测信号强度随探针摩尔浓度的降低而降低。探针的固定方法对信号强度也有一定的影响。紫外交联和高温烘烤均能使检测信号增强,而使用紫外交联的信号强度较高。[结论]地高辛检测的信号强度与探针的长度、浓度、固定方法以及核酸与膜的结合效率有关。     

猪肉质量安全可追溯系统屠宰环节的设计与实现

本文介绍猪肉质量安全可追溯系统建立过程中,关于屠宰环节的数据采集和信息系统建立的解决方案,包括采集数据项目的设计,胴体的标识和识读技术,标识和质量安全数据的现场采集,数据通过官方兽医的提交,最终服务于猪肉生产全过程的溯源系统的建立.     

快速检测动物病毒电镜技术

经多年研究，提出了适用于快速检出和鉴定动物病毒的系列电镜样品制备技术。该技术包括离子交换捕捉、微波幅射、高速离心、免疫金标方法。通过与常规法对比试验证实了离子交换捕捉法具有防腐保鲜作用，其浓缩样品的程度相当于超速离心法，简便易行，适用于远距离运送样品的检测；微波幅射改进法，不但加快了包埋制样速度，而且也提高了包埋质量；高速离心沉淀法快速简便，提高了检出率；免疫金标法不但提高了检出率，而且对于非典型及形态特征性不强的病毒粒子也能作出准确的诊断。可根据不同种类、不同目的的样品采取不同的制样方法，形成了系列化技术。此技术经农牧区、边疆、兽医生药厂、高等院校、科研单位以及海关进出口检疫等送检样品的验证，完全是可行的。应用该技术可快速、准确地诊断动物病毒病。     

苏云金芽孢杆菌cry基因芯片检测方法的研究

 建立了一种不经PCR扩增而直接应用寡核苷酸芯片从苏云金芽孢杆菌总DNA中检测cry基因的方法。对探针长度、浓度、总DNA含量、标记方法以及灵敏度等条件进行了研究。结果表明,用高浓度Klenow酶随机标记高浓度的总DNA与寡核苷酸探针(40～50mer、40μmol·L-1)杂交可用于检测Bt菌株中含有的cry基因;不同长度探针之间对杂交信号的影响存在显著性差异(P<0.01),而不同浓度的探针之间没有显著性差异。此方法的其它条件为杂交温度42℃、时间3h;检测的样品总DNA的灵敏度约为2.5μg;标记产物杂