转基因植物食用安全评价

2014年全球转基因植物种植面积达到1.815亿hm2,转基因植物商业化发展给全球农业和环境带来巨大收益,但是其安全性问题仍然受到广泛争议。目前,对转基因植物的安全评价在全球范围内已经建立起较为完善的体系,但是各国政府对评价程序的具体要求还存在差异。为了在法律法规层面规范转基因植物安全评价程序,中国农业部颁布了《转基因植物安全评价指南》,涵盖了详细的转基因植物及其产品的安全性评价内容。本文结合案例分析,对该指南中的食用安全评价部分详细解析和论述了包括营养学、毒理学、致敏性以及非期望效应等安全评价程序,旨在为我国转基因植物的食用安全评价提供有益的指导与借鉴。     

A Novel Particle Contact Assay with the Yeast Saccharomyces cerevisiae (8 pp)

Goal, Scope and Background   Numerous xenobiotics released into surface waters are transferred to suspended particulate matter and finally attached to sediments. Aquatic organisms may be exposed to them by direct particle feeding, by physical contact with contaminated surfaces as an exposure route, and by the uptake of dissolved contaminants after equilibration via the free water phase. In order to assess potential sediment toxicity, each of these exposure routes has to be addressed. This paper presents a newly developed particle contact assay that uses the fermentation performance of a specific Saccharomyces cerevisiae strain for the assessment of toxic effects in sediments. The test procedure is based on the characteristic feature of growing yeast cells to attach to sediment particles, which are also relevant for the accumulation of contaminants. The physical contact with lipophilic contaminants mirrors an exposition pathway for the direct uptake into the cells. In order to quantitatively characterize the toxic effects of particle attached pollutants on the fermentation performance, unpolluted native reference sediment was spiked with representatives for widely distributed anthropogenic contaminants. Methods   Saccharomyces cerevisiae was established as sensitive eukaryotic microorganism for the ecotoxicological assessment of particle attached anthropogenic contaminants in freshwater sediments. For this purpose, yeast cells were cultivated in sediment samples and the resulting fermentation performance was continuously measured. Sediments artifically spiked with HCB, PCB, g-HCH, DDT, and benzo(a)pyrene and solutions of each contaminant were comparatively investigated by means of their adverse effects on yeast fermentation performance. Additionally, four native river sediments characterized by increasing levels of pollution were assessed by the yeast particle contact assay, and simultaneously by standard aquatic tests with algae, daphniae, and luminescent bacteria using pore water and elutriates. Results of the bioassays were related to specific sediment contamination with respect to metals and organic priority pollutants. Results and Discussion   In sediments spiked with PCB and benzo(a)pyrene fermentation, performance was affected extensively below concentrations inhibiting fermentation in contaminant solutions. This suggests a high efficiency of the exposure route by physical contact. The fermentation performance was only slightly affected by single lipophilic pollutants, whereas mixtures of individually spiked sediments caused critically reduced fermentation performance suggesting additive synergistic effects. Native river sediments modestly to critically polluted by hazardous organic compounds lead to a slightly to dangerously reduced fermentation performance in the yeast contact assay. These inhibitory effects were much less pronounced in the standard bioassays conducted with algae, daphniae and luminescent bacteria, applying pore waters and elutriates as sample matrices. Using pore water, inhibition was measured only in the most polluted sediment, elutriates lead to a slight inhibition of the algal growth in the undiluted sample only. These results indicate an improved sensitivity of the yeast particle contact assay compared to the standard assays, due to uptake and physical cell contact as additional routes of exposure. Conclusion   The yeast particle contact assay is a valuable tool for the assessment of ecotoxicological potential in freshwater sediments. Since the assay addresses physical contact as an exposure route, it indicates bioavailability of lipophilic compounds in sediments. Outlook   The sensitive indication of bioavailable contaminants associated to sediment particles by the newly developed yeast particle contact assay recommends it as a complementary microbial bioassay in a test battery for assessing major pathways of contaminants in whole sediments.     

几种杀虫剂对南瓜实蝇蛹的毒力测定

在室内条件下采用浸渍法,分别测定了12种杀虫剂对南瓜实蝇蛹的毒力和二元混剂的共毒系数。供试杀虫剂对南瓜实蝇蛹的毒性大小依次为:毒死蜱>喹硫磷>氯唑磷>甲基异硫磷>辛硫磷>敌敌畏。高效氯氟氰菊酯、阿维菌素、敌百虫、丁硫克百威、噻虫嗪、高效氯氰菊酯对南瓜实蝇蛹的药效较差。敌百虫和辛硫磷(1:9)对南瓜实蝇蛹的LC50为96.2879mg/L,辛硫磷和毒死蜱(9:1)的共毒系数为590.77。     

三聚氰胺的毒理学研究进展

三聚氰胺(MA)化学性质稳定,在体内代谢不活泼,能以原体或同系物形式从尿液排出体外,在F344大鼠血浆中的半衰期为2.7h,在肾脏的清除率为2.5mL/min;MA对小鼠的半数致死量(LD50)为4550mg/(kg.bw),在国际化学物质急性毒性分级中属低毒性物质,接近微毒;MA对家兔、豚鼠和人眼无刺激作用;与三聚氰酸同时存在时毒性增加,毒性作用的靶器官为膀胱和肾脏;MA致癌性研究文献较少,结果也不一致,国际癌症研究中心认为MA对动物有致癌的可能性,但没有证据表明对人类有致癌作用。目前的研究认为,MA对环境和人的潜在危险性较小。对国内外关于三聚氰胺毒性的研究概况进行了总结,并综述了MA的污染及代谢、毒性和检测方法。     

草海桐链格孢叶斑病菌生物学特性及杀菌剂的室内筛选

西沙群岛草海桐链格孢叶斑病发生普遍,前期笔者鉴定了该病的病原菌为长柄链格孢菌（Alternaria longipes）。为进一步明确该病原菌的生物学特性及其对杀菌剂的敏感性,采用生长速率法对长柄链格孢菌的生物学特性进行了初步研究,并测定了苯醚甲环唑等13种杀菌剂对该病原菌的室内毒力。结果表明：该菌菌落最适生长培养基为马铃薯葡萄糖固体培养基（PDA）,其次是马铃薯蔗糖固体培养基（PSA）;适宜生长温度范围为25~30℃,最适生长温度为28℃;适宜生长pH为5.0~7.0,最适pH为6.0;最佳碳源为蔗糖,而果糖不利于菌落生长;最佳氮源为甘氨酸,而尿素不利于菌落生长;光照时间对菌落生长无显著影响。室内毒力测定表明,苯醚甲环唑水分散粒剂的抑菌效果最好,EC₅₀值为0.15 μg/mL,其次是氟硅唑乳油、己唑醇悬浮剂和戊菌唑乳油,其EC₅₀值分别为0.37、0.44和0.51 μg/mL,嘧菌酯悬浮剂和多菌灵可湿性粉剂的抑菌效果最差,EC₅₀值均大于3000 μg/mL。     

冬枣绿盲蝽成虫毒力测定与防治方法研究

通过室内和田间试验,比较了14种不同农药对冬枣绿盲蝽成虫杀伤力的差异。筛选了4种对冬枣绿盲蝽成虫具有较好杀灭作用的农药。室内试验结果表明:在14种农药中,对冬枣绿盲蝽成虫具有较好杀灭效果的有敌敌畏、氰戊菊酯、甲氰菊酯和氟虫腈。其中氟虫腈效果最好,LC50为81.57μg/g,其次为敌敌畏和氰戊菊酯,LC50分别为232.58μg/g、291.28μg/g。而大田试验,各种农药的防治效果较差。采用叶片喷雾法,5%氟虫腈乳油1000倍与20%甲氰菊酯乳油800倍防治效果最好,分别为65.94%、64.24%。土壤处理,基本无法控制成虫危害。因此必须采取多种方法才能有效控制绿盲蝽的危害。     

硫丹对水生生物毒理效应的研究进展

硫丹是一种有机氯杀虫剂,广泛应用于蔬菜、水果、茶叶、棉花、烟草、林木等害虫的防治.然而,在杀灭害虫、提高农产品产量的同时,硫丹也会对非目标生物,特别是对栖息在水环境中的生物体产生一定影响.本文综述了硫丹对水生生物急、慢性毒理效应,初步归纳了硫丹影响水生生物代谢的机制,阐述了硫丹在水体、底泥和生物体中的分布情况,旨为评价硫丹在水生生态系统中的环境行为及其对人类健康风险提供科学依据.     

中草药复合添加剂的小鼠急性毒性试验

为研究补气血、补肝肾中草药复合添加剂的急性毒性,试验采用灌胃法,选取SPF级昆明小鼠40只,雌雄各半,随机均分为4组（对照组、低剂量组、中剂量组和高剂量组）,以0.86 g/mL的中草药混悬液,每次0.4 mL/10 g灌胃,24 h内,高剂量组灌胃2次,每次0.4 mL;中剂量组灌胃2次,每次0.3 mL;对照组灌胃0.4 mL蒸馏水2次;低剂量组灌胃1次,0.2 mL。连续7 d,每天观察小鼠的精神状况和死亡情况。试验结束后,小鼠眼球采血,检测血液生理及生化指标;剖解小鼠,取心脏、肝脏、脾脏、肺脏、肾脏称重,计算脏器指数,制作病理组织切片,观察各脏器病理变化。结果显示,试验期间各组小鼠未见异常;中、高剂量组小鼠体重极显著高于对照组（P<0.01）;高剂量组肝脏指数、脾脏指数均极显著高于其他组（P<0.01）;试验组小鼠白细胞总数较对照组极显著升高（P<0.01）,但仍处在正常范围内;试验组小鼠血液肌酐显著降低（P<0.05）,中剂量组尿素氮显著低于对照组（P<0.05）;各组间其他生化指标均差异不显著（P>0.05）;病理组织切片结果显示,各组肝脏、脾脏和肾脏均无任何病理变化。综上所述,中草药复合添加剂对蛋白质代谢有明显的促进作用,可提高机体免疫力和肾脏功能,其最大给药量（34.4 g/kg生药）是临床成人每天用药（0.371 g/kg）的92.7倍,证明该药物无毒性,安全性好。     

阿维菌素，吡虫啉及其混剂对菜蚜的毒力测定和田间药效试验

采用浸渍法测定阿维菌素，吡虫啉及其混剂对菜蚜的毒力，阿维菌素与吡虫啉混配，各个配比均有增效作用，其中以LC50剂量1∶8的配比增效作用最大，毒性比率和共毒系数分别为1．82和194．20。阿维菌素与吡虫啉的混剂对菜蚜有较好的防治效果，室内结果在田间试验中得到验证。