Science and values in risk assessment: The case of deliberate release of genetically engineered organisms

To make more responsible decisions regarding risk and to understand disagreements and controversies in risk assessments, it is important to know how and where values are infused into risk assessment and how they are embedded in the conclusions. In this article an attempt is made to disentangle the relationship of science and values in decision-making concerning the deliberate release of genetically modified organisms (GMOs) into the environment. This exercise in applied philosophy of science is based on Helen Longino's contextual empiricism which attempts to reconcile the objectivity of science with its social and cultural construction. Longino distinguishes different levels of research on which values apparently contextual with respect to a given research program can shape the knowledge emerging from that program. Her scheme is applied for locating and identifying the values that affect environment risk assessments of the field experiments with GMOs. The article concludes with some provisional suggestions for the decision process and the role of scientists in it.     

Regulatory Oversight of Genetically Engineered Microorganisms: Has Regulation Inhibited Innovation?

/ Using detailed interviews with company representatives and researchers in the field, this paper examines the factors that might account for the slow pace of development of genetically engineered microorganisms (GEMs) intended for environmental release. We specifically analyzed the role of the regulatory system in shaping innovation. We identified at least two cases where industry decided to discontinue the development of a genetically engineered microbial product because of concerns over regulatory oversight. However, most often industry decisions to continue or halt development of GEMs were based on an evaluation of the particular product's efficacy and potential for profitability. Thus the inability of GEMs to perform up to expectations in the field, rather than the regulatory constraints, appears to be the factor responsible for the slow pace of development. KEY WORDS: Genetically engineered microorganisms; Biotechnology; Regulation of biotechnology; Innovation; Environmental release     

醌还原酶 醌类化合物对偶氮染料脱色的作用

外加醌类化合物作介体,利用细菌胞内的醌还原酶考察基因工程菌Escherichia coli YB对偶氮染料的脱色能力,以及甲基氢醌预处理对E. coli JM109和厌氧污泥脱色的影响.结果表明,介体2羟基1,4萘醌（lawsone,LQ）的存在对胞内过量表达醌还原酶AZR的E. coli YB的脱色能力有显著的促进作用,0.2 mmol·L^-1 LQ存在下,苋菜红（1 mmol·L^-1）在2 h内可脱色75%.LQ存在时E. coli YB对高浓度的染料也有脱色效果,8 h可使苋菜红（5 mmol·L^-1）脱色50%左右.与LQ相比,甲萘醌作为介体对脱色的促进效果较差,2.5 mmol·L^-1甲萘醌存在下脱色70%需12 h.LQ存在时E. coli YB对苋菜红的重复脱色能力稳定,12 h内能完成4次重复脱色.LQ的存在对于结构较复杂的2种偶氮染料酸性大红GR和活性艳红K2BP的脱色也有促进作用,在最适LQ浓度下,分别在9 h和30 h脱色70%.甲基氢醌预处理对E. coli JM109和厌氧污泥的脱色能力都有促进作用.预处理后在LQ存在下,E. coli JM109在5 h可脱色苋菜红（1 mmol·L^-1）80%左右,而污泥可在11 h脱色75%以上.     

Herbicide Resistant Sugar Beet – What Is the Problem?

Risk assessment studies of herbicide resistant sugarbeet have revealed no risks to human health or the environment.Indeed it appears that commercial growth of this crop mightsecure benefits such as decreased pesticide use and increasedbiodiversity. However, widespread resistance to GM crops such asherbicide resistant sugar beet still persists in Europe. It isargued that this is not just because people do not know therelevant facts. Rather it is because popular resistance to GMfood is driven in part by concerns other than the fear ofnarrowly defined risks to health and the environment. These otherconcerns include an aversion to commercial monopoly and anegative view of pesticide use in general. Herbicide resistantsugar beet may also be perceived as a ``Trojan horse,' i.e., acrop whose licensing would create a precedent and make it morelikely that other, less environmentally friendly, crops will beapproved within the current strictly technical and science-basedrisk assessment procedures. To meet these public concerns, a kindof technology assessment reflecting factors such as benefits andconsumer choice is called for.     

人工纳米颗粒在水体中的行为及其对浮游植物的影响

人工纳米颗粒(engineered nanoparticles,ENPs)因其特殊的尺寸效应及良好的光学、磁学等性质,已被广泛应用于医药、生物成像以及工业产品等领域.在生产、使用和排放的过程中,ENPs通过不同途径不可避免地进入水体,因此ENPs在水体中的行为和生物安全性也引起了人们的极大关注.在水生生态系统中,浮游植物作为初级生产者,为自身以及其他营养级生物提供营养物质、能量和氧气,因此受到ENPs的影响是难以估算的.近年来已有大量的研究证实ENPs对生物有毒性效应,但ENPs进入浮游植物体内的机制以及ENPs在浮游植物体内的生物运输和转化的报道较少,并且这方面的机制仍不甚明确.本文重点介绍了纳米材料进入水体的途径,在水体中的行为以及对浮游植物的生物效应的最新研究进展,但这方面的机制研究需要进一步深入.     

转Bt基因工程菌BioP8在环境中的消长动态及生物学效应

2001~2004年,在河北省保定市对转Bt基因荧光假单胞菌工程菌BioP8进行了环境释放,并跟踪调查该工程菌在田间的定殖、扩散、田间防效以及对田间节肢动物群落的影响.结果表明,BioP8在甘蓝叶、根及土壤中均能定殖、存活,在植物根部存活能力较强.在施药后d3,BioP8菌密度均达最高值,之后趋于衰减;BioP8对甘蓝田中天敌有较明显的保护作用,对田间节肢动物群落物种丰富度有一定的影响,BioP8防治区的节肢动物个体总量介于化防区和空白对照区的个体总量.图2表1参7     

绿色荧光蛋白标记阿特拉津降解基因工程菌的特性

通过转化绿色荧光蛋白基因质粒,对阿特拉津降解基因工程菌进行标记.转化后,绿色荧光蛋白在细胞内表达情况良好.在含抗生素的LB培养基中,绿色荧光蛋白的表达水平高于LB培养基和基础培养基.在细胞生长的稳定期,绿色荧光蛋白表达水平高于停滞期和对数生长期.绿色荧光蛋白基因质粒转化和表达,不会对基因工程菌原有的降解能力产生影响,而且绿色荧光蛋白的表达水平和降解活性存在接近线形的正相关关系.荧光蛋白标记细胞投加到反应器活性污泥中,会以2种状态存在:游离态和附着态,而且初期游离态细胞的数量大于附着态细胞的数量.     

利用基因工程菌BL21处理有机磷混合农药废水的研究

研究了悬浮状态和固定化状态的基因工程菌BL21对有机磷混合农药废水的降解特性.工程菌能快速、高效地降解有机磷混合农药,其最适底物是对硫磷,而马拉硫磷不能被工程菌降解.不同农药降解速率的差别造成了不同有机磷农药的降解过程需要用不同的动力学模型来描述.比较固定化状态和悬浮状态的工程菌的降解效果可知,固定化工程菌的降解活性较后者明显降低,其比降解速率大约仅为后者的20%.考察固定化工程菌长期运行的效果,发现其降解活性保存良好,工程菌稳定性大大提高,未出现固定化细胞溶涨、破碎现象.固定化后,工程菌的比降解速率虽然比悬浮工程菌降低了,但固定化工程菌更适用于长期运行的废水处理系统.     

工程菌及其固定化细胞对有机磷农药的降解

将抗性库蚊解毒酶酯酶B1基因片段引入融合表达载体pThioHisA中,转化入大肠杆菌DH5α,在IPTG诱导下,经过8h,酯酶B1在大肠杆菌中获得融合高效表达。重组质粒pThioHisA-B1表达的酯酶融合蛋白具有较高的酯酶B1活性,能高效降解酯酶的特异性底物α-乙酸萘酯(α-NA)和β-乙酸萘酯(β-NA),将工程菌固定化后,固定化细胞在3h内对1000mg/L的甲基对硫磷降解率>65%。     

钚在某处置工程屏障水环境中化学形态及影响因素

针对某放射性废物包装容器回填处置工程屏障结构特征,采用岩体裂隙水浸泡工程屏障样品的方式,在对各平衡水样化学成分分析的基础上,利用地球化学模拟软件EQ3/6对钚在回填工程屏障水环境中的存在化学形态进行了模拟计算,得出钚在回填工程屏障水环境中主要以Pu(Ⅳ)价态Pu(OH)5-形式存在,同时水环境中pH值和Eh值的变化皆会影响钚的存在化学形态和价态。