Research and field monitoring on transgenic crops by the Centro Internacional de Mejoramiento de Maíz y Trigo (CIMMYT)

The International Maize and Wheat Improvement Center (CIMMYT) aims to genetically enhance both crops and generate public sector-provided products for the resource poor, e.g., drought tolerant wheat and insect resistant maize, and through international–national partnerships facilitate the acquisition of improved germplasm for non-mandate crops in the cropping systems where maize and wheat thrives; e.g., GM-papaya through a national food security undertaking in Bangladesh. The Center also engages in public awareness campaigns in projects such as Insect Resistance Maize for Africa (IRMA), which includes food, feed and environmental safety, monitoring of resistance and establishment of refugia, non-target effects and gene flow. Monitoring of genetic resources is a wide concern among the centers of the Consultative Group on International Agricultural Research (CGIAR), with an emphasis on the quality of gene banks. Decisions, policies and procedures about monitoring should be science-based, and this requires education, an area where CIMMYT and other CGIAR centers can play an important role. There will be a need to continue to evaluate the need for, and type of monitoring, as new (and unique) products are developed and released in the emergent economies of the world.     

转基因抗虫玉米的定量检测

建立高效、快速、准确的抗虫转基因玉米MIR162转化体特异性实时荧光PCR(real-time PCR)检测方法。采用SYBR Green I和Taqman探针2种定量方法对抗虫转基因玉米MIR162进行了检测研究。SYBR Green I法MIR162转化体特异性片段和内标基因zSSIIb的熔解曲线均表现为单一峰,扩增特异性强;二者的扩增效率均在90%~100%之间,标准曲线相关系数R2均大于0.998。2种定量方法的检测限(LOD)均为24个拷贝,定量限(LOQ)为48个拷贝,灵敏度较高。重复测试结果表明,SYBR Green I法的标准偏差(SD)变化范围为0.05~0.13,相对标准偏差(RSD)范围为0.17%~0.40%,Taqman探针法的SD变化范围为0.03~0.14,RSD范围为0.11%~0.44%,说明2种定量检测方法具有良好的重复性和精密度。对MIR162含量为3%、1%和0.5%的混合样品的定量结果为：3.13%、1.09%、0.53%（SYBR Green I法）和3.07%、1.02%、0.50%（Taqman探针法）,RSD均小于10%,T检验分析表明2种定量方法定值结果差异不显著。本研究建立的2种实时荧光定量PCR均可有效对转基因玉米MIR162进行定量检测,可根据不同实际需求及实验室条件进行选择相应的检测方法。     

糯玉米改性淀粉的制备及其在速冻食品中的应用研究进展

糯玉米淀粉因独特的结构具有良好的冻融稳定性,在速冻食品中有着巨大的潜在利用价值,但原淀粉自身存在耐酸性、耐高温、耐剪切性较差等缺点,限制了其在食品工业中的应用。为了改善糯玉米淀粉的理化特性和加工性能,需要对原淀粉进行改性处理。概述了糯玉米淀粉常见的改性方法,介绍了糯玉米改性淀粉在速冻食品中的应用,并对糯玉米改性淀粉的研究现状和在速冻食品中的应用进行了分析和展望,为糯玉米改性淀粉在速冻食品中的应用提供一定的理论依据。     

茶油皂脚脂肪酸甲酯制备的水溶性改性胺固化物性能研究

以茶油皂脚脂肪酸甲酯制备的水溶性改性胺(CA-921)与水性环氧树脂固化,通过热重分析、差示扫描量热法(DSC)、机械性能测试及扫描电镜分析,研究了环氧树脂分散相粒子的粒径和黏度、环氧基与胺氢物质的量之比及固化温度对固化物性能的影响.研究结果表明,黏度及粒径均较小的水性环氧乳液AB-EP-20与固化剂CA-921复配所...     

平菇专用保鲜膜常温MAP保鲜试验

以3种特制抗菌膜、1种常规保鲜LDPE膜和1种普通LDPE膜为试材,研究平菇常温不同特性保鲜膜MAP保鲜效果,确定最佳平菇保鲜膜.结果表明,日本产保鲜膜和国家农产品保鲜中心研制的抗菌膜包装平菇后于常温下贮藏8天,基本保持平菇原有的品质,失重率小于2%.     

转基因抗虫棉对农户生产行为的影响分析

以河北主产棉区340个农户2002-2003年的问卷调查和关键人物访谈为依据,分析了转基 因抗虫棉对农户生产行为的影响。结果表明,转基因抗虫棉的应用影响或改变了农户的植棉意向、抗 虫棉种子选择,棉田害虫防治及植棉技术需求等生产行为。     

Discussion on Calculation Pattern of Concrete Filled Steel Tube with Dumbbell shaped Section

Based on the structural feature of dumbbell shaped section of concrete filled steel tube (CFST), a combined spatial beam element is presented. In this structure, two steel tubes, two core concretes, one web and the concrete in web cavity are firstly considered as general spatial beam elements, then they are assembled into a spatial combined beam element according to the plane hypothesis and transformation matrix formed from master and slave nodes. A FORTRAN program for CFST arch with dumbbell shaped section has been developed, and the numerical example shows that the steel tubes and core concretes bear mainly the axial forces with small moments, thus, a modified formula for lattice column method to calculate axial forces of the upper and lower limbs of CFST with dumbbell shaped section is deduced. Comparison of the results from the modified formula with those from an example indicates that the modified formula gives relatively accurate results.      

转基因作物安全研究进展及南繁转基因生物安全管理对策

本文从生物多样性、生态系统和人畜安全三方面概述了转基因作物生物安全研究进展,并介绍了全世界转基因生物安全评价原则与方法和我国转基因作物安全管理法规.表明转基因作物存在潜在的生物安全风险,全世界正在积极构建转基因生物安全管理体系.通过对我国南繁转基因环境安全问题和情况进行分析,认为南繁地区有成为染缸的潜在威胁.为保护南繁...     

草莓的保鲜现状研究

草莓味道鲜美,受到人们的喜爱,但是却难以保藏。目前,草莓的保藏方法主要是控制温度,并使用保鲜剂进行贮藏。控制温度一般通过冷藏库实现。草莓控温在冰点以上进行冰温贮藏比普通的冷藏效果要好。而使用气调库、气调包装则能更好地保持草莓的新鲜度。     

实时荧光PCR技术定量检测转基因大豆方法的研究

以转基因大豆Roundup Ready为材料，通过特异性引物和探针，对转基因大豆中外源基因cp4-epsps进行了定量检测。研究发现Taqman荧光探针法和SYBR荧光染料法均可作为转基因大豆定量检测的方法，但前者比后者具更高的检测灵敏度和精确度，其检测阈值可降到0.05%，变异系数为0.09%~0.53%。在此基础上，建立和优化了Taqman探针实时荧光定量PCR检测技术体系，有助于提高转基因作物及产品的生物安全性定量检测的准确度和可靠性。