Highly tunable thiosulfonates as a novel class of cysteine protease inhibitors with anti-parasitic activity against Schistosoma mansoni

The development of a new class of cysteine protease inhibitors utilising the thiosulfonate moiety as an SH specific electrophile is described. This moiety has been introduced into suitable amino acid derived building blocks, which were incorporated into peptidic sequences leading to very potent i.e. sub micromolar inhibitors of the cysteine protease papain in the same range as the vinyl sulfone based inhibitor K11777. Therefore, their inhibitory effect on Schistosoma mansoni, a human blood parasite, that expresses several cysteine proteases, was evaluated. The homophenylalanine side chain containing compounds 27–30 and especially 36 showed promising activities compared with K11777 and warrant further investigations of these peptidic thiosulfonate inhibitors as new potential anti-parasitic compounds.     

转mCry1Ac基因玉米BT799对斑马鱼的生态毒理学效应

转基因作物的饲用安全性问题一直是人们关注的焦点之一.为评估转mCry1Ac基因玉米BT799对鱼类的生态毒理效应,本研究以斑马鱼为受试动物,设置5个处理:含20%转基因玉米膨化饲料组(GMF)、含20%亲本玉米膨化饲料组(PF)、转基因玉米粉(GMM)、亲本玉米粉(PMM)以及商业饲料对照组(CF),通过98 d的喂养试验,调查斑马鱼的生长表现、组织病理、繁殖、肝脏中抗氧化酶活性及敏感蛋白mRNA的表达水平.结果表明:转mCry1Ac基因玉米对斑马鱼的各项生长指标、肝脏、脑和肠道的组织病理、产卵量、受精卵孵化率、肝脏中超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性,以及SOD、CAT、热激蛋白70(HSP70)和卵黄蛋白原(VTG)mRNA表达量均无显著影响.但在试验后期,饲料组(GMF和PF)和玉米粉组(GMM和PMM)斑马鱼的体重、体长和特定生长率显著低于商业饲料组;饲料组斑马鱼的孵化率显著低于玉米粉组和商业饲料组;饲料组(3.85±0.76)雄鱼肝脏中的VTG mRNA表达量显著高于玉米粉组(1.60±0.56).研究表明,转mCry1Ac基因玉米对斑马鱼没有明显生态毒理效应,但由于配制的膨化饲料与商业饲料在营养成分和适口性上的差异,可能导致个别指标与商业饲料组相比有显著差异.     

Modeling spatial dependence and economic hotspots in landowners’ willingness to supply bioenergy crops in the northeastern United States

This paper investigates the spatial heterogeneity of landowners’ willingness to supply three bioenergy crops: switchgrass, Miscanthus, and willow, in the northeastern United States. Spatial heterogeneity might arise for several reasons. For example, landowners closer to bioenergy processing plants might be more likely to be willing to supply bioenergy crops, and landowners who are more willing to supply bioenergy crops may be spatially clustered because they share similar land attributes, demographics, experiences, and/or values. Using high‐resolution GIS data related to the location of pellet plants utilizing bioenergy crops and survey data related to landowners’ characteristics including spatial location, we estimate a spatial probit model to explain the variation in individual‐specific reservation prices (RPs)—the feedstock price at which landowners become willing to supply a bioenergy crop. We find that respondents’ RP is lower the closer they live to their nearest pellet plant and spatial dependency is only present for switchgrass supply. We also identify three economic hotspots (areas with high potential supply and low RPs) for each bioenergy crop. We believe that bioenergy supply chains could be developed around these hotspots.     

RNAi转基因作物安全评价研究进展

在秀丽隐杆线虫中首次发现双链RNA(dsRNA)能特异性地导致基因沉默(RNAi)现象后,人们开始大量地研究RNAi技术,并将其应用于功能基因的研究,来提高作物的抗性和改良遗传育种等。本文详细介绍了RNAi的技术原理,并且对RNAi技术与传统转基因技术的区别进行分析,阐述了该技术具有重要的生物学意义,以及在农作物害虫防治领域的占据独特优势。基于RNAi技术存在的潜在脱靶效应,从改良植物、靶标生物和生态环境的3个方面具体分析该技术可能存在的风险,为RNAi技术的风险评估提供参考。由于RNAi技术仍存在风险,为了维护生态多样性和保障人们的人身安全,应尽快建立起符合实际需求的安全性评价方法,本文针对RNAi转基因作物的环境安全和食用安全2个方面的评估方案进行概述。RNAi技术对减少害虫数量、提高水稻产量、降低种植成本以及减少化学农药污染、促进农业可持续发展来说具有重要意义,但该技术仍存在风险,需要进一步监管和研究,建立完善的生态评价系统,让RNAi技术在农业生产上发挥作用。     

几种氧代丙酸化合物在诱捕白纹伊蚊中的应用

为了从氧代丙酸化合物中筛选出对白纹伊蚊Aedes albopictus具有良好引诱效果的化合物,采用陷阱诱捕法分别测定了丙酮酸（α-氧代丙酸）、3-甲氧基-2-甲基-3-氧代丙酸、3-(苄氧基)-3-氧代丙酸和3-氨基-3-氧代丙酸4种氧代丙酸化合物及丙酸对白纹伊蚊成虫的诱捕效果。结果表明,在供试的5种化合物中,α-氧代丙酸、3-甲氧基-2-甲基-3-氧代丙酸和3-(苄氧基)-3-氧代丙酸3种氧代丙酸化合物及丙酸的诱捕效果显著,同剂量的各化合物对白纹伊蚊的诱蚊效果依次是3-甲氧基-2-甲基-3-氧代丙酸>3-(苄氧基)-3-氧代丙酸>α-氧代丙酸=丙酸。相同质量α-氧代丙酸∶3-(苄氧基)-3-氧代丙酸=1∶1至1∶2的配方比,具有协同增效作用,平均累计诱捕量均显著优于单组分α-氧代丙酸、3-(苄氧基)-3-氧代丙酸和对照纯水（P<0.05）。其中最优配方比是α-氧代丙酸∶3-(苄氧基)-3-氧代丙酸=1∶2,平均累计诱捕量比单组分α-氧代丙酸增加45.45%,比单组分3-(苄氧基)-3-氧代丙酸增加32.33%和比对照纯水增加73.11%（P<0.05）。现场诱蚊试验结果表明,根据相似相溶原理将液体的氧代丙酸（α-氧代丙酸、3-甲氧基-2-甲基-3-氧代丙酸）分别与固体的氧代丙酸（3-(苄氧基)-3-氧代丙酸）混配并结合陷阱诱捕器,能够显著提高对白纹伊蚊的持效性及诱捕数量（混合物60 d的累计诱蚊总数量是单组分的1.28~2.15倍）。研究结果为进一步开发适用于家居办公环境中使用的诱蚊剂提供了研究基础。     

转基因抗虫作物对捕食性瓢虫的安全性研究进展

转基因抗虫作物的商业化种植带来了显著的经济、生态和社会效益,对转基因抗虫作物的安全性评价也一直是国内外学者研究的热点。对生物非靶标效应的研究是转基因抗虫作物安全性评价的重要组成部分,农田天敌类生物是其中的重点内容之一。瓢虫是农田生态系统重要的捕食性天敌,评价其在转基因抗虫作物田间是否能通过捕食猎物或取食花粉而接触到杀虫蛋白并富集于体内,进而对自身产生一定的非靶标效应,这对捕食性瓢虫的安全性研究具有重要的意义。本文从捕食性天敌瓢虫的生命表参数、行为功能参数、田间群落参数及体内微环境指标等方面综述了转基因抗虫作物对瓢虫的安全性研究进展,并对后期转基因抗虫作物对田间捕食性天敌的研究方向提出了建议,以期为转基因抗虫作物的环境安全性研究提供理论指导和为进一步完善转基因抗虫作物对瓢虫安全性评价的技术体系提供系统的数据资料。     

A comparative spin trapping study of the interaction of hypobromous and hypochlorous acids with <Emphasis Type="Italic">tert</Emphasis>-butyl hydroperoxide

Hypochlorite (HOCl/OCl^?) and hypobromite (HOBr/OBr^?) are shown to react with tert-butyl hydroperoxide with close rate constants (10.8 and 8.9 M^?1 s^?1, respectively). Using a spin trap α-(4-pyridyl-1-oxide)-N-tert-butyl nitrone, both reactions are shown to proceed through decomposition of the hydroperoxide yielding butylperoxyl [˙OOC(CH₃)₃] and butoxyl [˙OC(CH₃)₃] radicals in a ratio depending on the hydroperoxide concentration. Thus, like hypochlorite, hypobromite can generate free radicals in reactions with organic hydroperoxides, which can be important for intensification of free-radical processes, e.g., lipid peroxidation at the chain branching stage.     

Describing maize (Zea Mays L.) landrace persistence in the Bajío of Mexico: A survey of 1940s and 1950s collection locations

Passport data for Mexico’s Guanajuato State were used to locate the sites where maize was collected in the 1940s and 1950s in an effort to document and conserve diversity. A map presenting survey points illustrates that collections have occurred repeatedly in the same locations. Observations of these locations reveal that urbanization and industrialization, not high yielding varieties, are displacing traditional varieties. Non-linear principal components analysis was used to assess associations between variables in areas where maize persists. Landraces appear to be associated with mountains and mesas, mixed cropping, little or no access to irrigation and areas classified as having low agricultural capacity; conversely, landraces have more commonly been replaced in areas of high agricultural capacity. The areas of high agriculture capacity, located in the riparian areas and plains, also have been the easiest to develop for urban and industrial use. Increasingly high rates of urbanization and development in areas of high agriculture capacity will impede the conservation of crop diversity in these areas.     

Intellectual property, genetically modified crops and bioethics

The implementation of a new technology is almost always surrounded by a debate on the moral and social implications that may arise. The debate with regard to genetically modified (GM) crops has been one of the longest and most controversial. However, one area of the debate that receives less attention is the role that intellectual property can play. The introduction of an effective and yet appropriate intellectual property system addressing society's particular needs can eliminate some of these issues. This paper looks at whether the situation in Europe is meeting our current needs and also addresses the role intellectual property can play in the debate over the introduction of GM crops in developing countries.     

信息素在文物害虫防治中的应用与展望

文物害虫会对文物古建筑造成不可逆的破坏,因此害虫防治是文物保护的重要工作。随着博物馆引入有害生物综合防治（Integrated Pest Management,IPM）策略,博物馆的害虫防治也开始遵循“预防为主,防治结合”理念。昆虫体外信息素是IPM中重要的技术手段。该技术可对害虫进行监测与诱杀,有利于对害虫发生规律的研究与数量控制。且信息素具有用量少,不接触文物等优点。本文概述信息素的发展、种类与功能,整理了文物害虫信息素及其应用中的遇到的问题,并展望信息素的应用前景。