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转基因植物环境安全评价策略   总被引:4,自引:0,他引:4  
构建完善的转基因植物环境安全评价技术体系是保障转基因生物产业健康发展的重要组成部分。本文综述了转基因植物环境安全评价技术发展历程与趋势,归纳了转基因植物环境安全评价的思路与内容。转基因植物环境安全评价应分为潜在风险分析、风险假设验证、风险特征描述等3个步骤,并采用逐层评价模式;安全评价应贯穿转基因植物新品种研发与产业化全程,包括应用前预测、研发中筛选、推广前评价、推广后监测。此外,基于科学性和个案分析原则,本文对复合性状、非生物胁迫抗性等新型转基因植物环境安全评价策略进行了探讨。  相似文献
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【背景】转基因手段已成为改良玉米品种的重要途径之一,具有诸多优点的转基因玉米越来越受到人们的青睐。转基因玉米带来巨大经济和社会效益的同时,其安全风险问题也引发人们广泛关注,因此有必要对转基因玉米进行生物多样性影响评价。【方法】采用直接观察法和陷阱法对种植转EPSPS基因抗除草剂玉米CC-2及其对应的非转基因对照郑58的田间节肢动物进行调查,分析其群落组成、群落结构及主要类群动态。【结果】转基因玉米CC-2无论是喷施除草剂还是不喷施除草剂处理,与其对应的非转基因对照郑58相比,田间节肢动物群落组成、群落结构,以及田间主要节肢动物类群动态均无显著差异。【结论与意义】初步认为转EPSPS基因抗除草剂玉米CC-2对节肢动物多样性无安全风险,为转EPSPS基因抗除草剂玉米的推广提供一定生态安全数据。  相似文献
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免疫调节因子白细胞介素-2(IL-2)具有中枢镇痛功能。实验采用基因定位突变技术,获得系列IL-2突变体,并测定其免疫学活性和镇痛能力,发现无免疫学活性的IL-2突变体20Leu-IL-2仍具有中枢镇痛能力,而44Leu-IL-2,45 Val-IL-2虽保留了免疫学活性,但其镇痛能力显著性下降或消失,阿片受体拮抗剂纳洛酮能够阻断IL-2的中枢镇痛作用,而不能影响IL-2对CTLL-2细胞的增殖作用。抗内源性阿片肽血清与IL-2能发生明显的交叉反应。实验结果提示,IL-2分子是通过由第45位Tyr残基及空间上相近的Phe残基等组成的镇痛功能位点与阿片受体相结合而发挥镇痛效应。  相似文献
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Li Y  Fu L  Wong AM  Fan YH  Li MX  Bei JX  Jia WH  Zeng YX  Chan D  Cheung KM  Sham P  Chua D  Guan XY  Song YQ 《PloS one》2011,6(1):e14562
Nasopharyngeal carcinoma (NPC) is a malignancy of epithelial origin. The etiology of NPC is complex and includes multiple genetic and environmental factors. We employed case-control analysis to study the association of chromosome 6p regions with NPC. In total, 360 subjects and 360 healthy controls were included, and 233 single nucleotide polymorphisms (SNPs) on 6p were examined. Significant single-marker associations were found for SNPs rs2267633 (p = 4.49 × 10(-5)), rs2076483 (most significant, p = 3.36 × 10(-5)), and rs29230 (p=1.43 × 10(-4)). The highly associated genes were the gamma-amino butyric acid B receptor 1 (GABBR1), human leukocyte antigen (HLA-A), and HLA complex group 9 (HCG9). Haplotypic associations were found for haplotypes AAA (located within GABBR1, p-value = 6.46 × 10(-5)) and TT (located within HLA-A, p = 0.0014). Further investigation of the homozygous genotype frequencies between cases and controls suggested that micro-deletion regions occur in GABBR1 and neural precursor cell expressed developmentally down-regulated 9 (NEDD9). Quantitative real-time polymerase chain reaction (qPCR) using 11 pairs of NPC biopsy samples confirmed the significant decline in GABBR1 and NEDD9 mRNA expression in the cancer tissues compared to the adjacent non-tumor tissue (p<0.05). Our study demonstrates that multiple chromosome 6p susceptibility loci contribute to the risk of NPC, possibly though GABBR1 and NEDD9 loss of function.  相似文献
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【背景】土壤微生物是维持土壤生态系统中生物活性的重要组成部分,土壤细菌作为土壤中数量最丰富、分布最广泛的微生物类群,其结构多样性和动态分布对土壤生态系统的稳定具有重要意义。因此,评价转基因作物的安全性必须考虑转基因产物对土壤细菌的影响。【方法】在大田条件下,连续2年以转cry1Ie基因抗虫玉米和受体对照玉米为研究材料,采用变性梯度凝胶电泳(PCR-DGGE)和磷脂脂肪酸(PLFA)研究转cry1Ie基因抗虫玉米和受体对照玉米不同生育期根际土壤中细菌群落结构的变化。【结果】PLFA分析结果显示,2012年,转cry1Ie基因抗虫玉米和受体对照玉米间微生物总量在拔节期有显著性差异,其他时期无显著性差异;然而,土壤中细菌微生物总量和革兰氏阳性菌与革兰氏阴性菌微生物量比值在检测的4个时期均无显著性差异;其中,革兰氏阳性菌与革兰氏阴性菌比值均大于1。2013年的整个生育期内,转cry1Ie基因抗虫玉米和受体对照的微生物总量、细菌微生物量、革兰氏阳性菌与革兰氏阴性菌微生物量比值均无显著性差异。DGGE结果显示,2012年和2013年玉米的4个生育时期内,玉米根际土壤细菌群落结构相对较稳定,同一生育期转cry1Ie基因抗虫玉米和受体对照玉米间无显著性差异,且根际细菌群落结构相似性均达到较高水平,与PLFA检测结果大体一致。【结论与意义】2年的数据均表明,转cry1Ie基因抗虫玉米对土壤中细菌群落结构无显著性差异,可为转cry1Ie基因抗虫玉米安全性评价提供理论依据。  相似文献
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In the development of structural equation models (SEMs), observed variables are usually assumed to be normally distributed. However, this assumption is likely to be violated in many practical researches. As the non‐normality of observed variables in an SEM can be obtained from either non‐normal latent variables or non‐normal residuals or both, semiparametric modeling with unknown distribution of latent variables or unknown distribution of residuals is needed. In this article, we find that an SEM becomes nonidentifiable when both the latent variable distribution and the residual distribution are unknown. Hence, it is impossible to estimate reliably both the latent variable distribution and the residual distribution without parametric assumptions on one or the other. We also find that the residuals in the measurement equation are more sensitive to the normality assumption than the latent variables, and the negative impact on the estimation of parameters and distributions due to the non‐normality of residuals is more serious. Therefore, when there is no prior knowledge about parametric distributions for either the latent variables or the residuals, we recommend making parametric assumption on latent variables, and modeling residuals nonparametrically. We propose a semiparametric Bayesian approach using the truncated Dirichlet process with a stick breaking prior to tackle the non‐normality of residuals in the measurement equation. Simulation studies and a real data analysis demonstrate our findings, and reveal the empirical performance of the proposed methodology. A free WinBUGS code to perform the analysis is available in Supporting Information.  相似文献
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