PCR—GeneScan法检测转基因产品

利用PCR－GeneScan技术检测转基因在豆和转基因玉米,该方法的特点是PCR扩增反应后,用Genescan扫描替代琼脂糖凝胶电泳检测PCR产物。用此方法共检测了35S启动子,NOS终止子和抗除草剂（草甘膦）和抗虫（Bt)4种转基因成分,结果显示,本方法比传统的PCR一琼脂糖凝胶电泳法灵敏度高,重现性好,结果易判断,为分析检测转基因产品提供了一个实用,灵敏的方法。     

Soil biodiversity: myth,reality or conning?

The study of soil microarthropod biodiversity is illustrative of problems that are related to other soil organisms (fungi, for instance) or that can be found in other environments (canopy, oceanic sediments, hosts accommodating parasites, etc.). Indeed, the contribution of the soil fauna to global biodiversity remains an enigma even though, in recent years, it has received considerable attention. Our contention is that the debate on soil biodiversity will remain open – and even sterile – as long as adequate sampling methodologies are not set up, critically evaluated and largely used.
First, a critical review of the sampling strategies used for soil microarthropods is presented. In addition to an extensive compilation of publications on extraction method efficiency, articles from two journals devoted to soil biology are compared for two five-year periods (before and after Erwin's papers and before and after Rio). The most frequently used extraction methods (over 90% of studies) have a poor numerical efficiency (e.g. 7–26% for the Berlese-Tullgren funnels) and also are selective with respect to their efficiency for certain taxa (variable taxonomic and functional efficiency), 75% of studies are restricted to the upper 10 cm of soil and therefore overlook largely the microarthropod populations, some groups are often neglected, however diversified they are, and the taxonomic resolution tends to become impoverished in recent years.
In the second part of our study, the importance of bias induced by inadequate or restricted sampling strategies on biodiversity estimates is evaluated: densities are dramatically underestimated (down to 14 times less); conversely species aggregation, a factor advocated to explain the existence of numerous soil species, is overestimated; some functional groups may be quite overlooked; the species distribution along a gradient deduced from the sampling may be rather different from that really existing in the soil and interfere with the evaluation of β-diversity; species richness is often crudely underestimated (down to 50%).
Overall, at most 10% of soil microarthropod populations have been explored and 10% of species described. Obviously, much has still to be done to evaluate soil microarthropod biodiversity and afortiori understand the mechanisms underlying it. Improving and renewing the soil sampling strategy is thus a prerequisite to any real advance in our knowledge of this fascinating and obscure domain.     

PCR detection of genetically modified soya and maize in foodstuffs

The detection of genetically modified foodstuffs is becoming both a food sales and legal necessity. This study reports a rapid DNA extraction/PCR-based method for the detection of genetically modified soya (GMS) and maize (GMM) in mixed samples of transgenic and unmodified soybeans and maize kernels, and a variety of processed samples including soya flour, soya protein isolates, extruded defatted soya, acid- and alcohol-precipitated soya concentrates, soya lecithin, maize grits, seasoned corn puffs and salted corn chips. The presence of GMS DNA was determined with two pairs of primers directed towards different GMS target sequences and GMM by one primer pair. In addition, a multiplex PCR reaction which utilises an internal positive control was developed for both genetically modified organisms (GMOs). Results indicated that the methods are sensitive and specific enough to detect GMS down to a level of 0.01% dry weight in single-product PCRs and 0.1% in multiplex PCRs and GMM down to 0.001% dry weight in single-product PCRs and 0.01% in multiplex PCR. The methods are considered to represent a viable route for the commercial detection of GMS and GMM in foodstuffs.     

Detection of airborne genetically modified maize pollen by real-time PCR

The cultivation of genetically modified (GM) crops has raised numerous concerns in the European Union and other parts of the world about their environmental and economic impact. Especially outcrossing of genetically modified organisms (GMO) was from the beginning a critical issue as airborne pollen has been considered an important way of GMO dispersal. Here, we investigate the use of airborne pollen sampling combined with microscopic analysis and molecular PCR analysis as an approach to monitor GM maize cultivations in a specific area. Field trial experiments in the European Union and South America demonstrated the applicability of the approach under different climate conditions, in rural and semi-urban environment, even at very low levels of airborne pollen. The study documents in detail the sampling of GM pollen, sample DNA extraction and real-time PCR analysis. Our results suggest that this 'GM pollen monitoring by bioaerosol sampling and PCR screening' approach might represent an useful aid in the surveillance of GM-free areas, centres of origin and natural reserves.     

Environmental impact of herbicide regimes used with genetically modified herbicide-resistant maize

With the potential advent of genetically modified herbicide-resistant (GMHR) crops in the European Union, changes in patterns of herbicide use are predicted. Broad-spectrum, non-selective herbicides used with GMHR crops are expected to substitute for a set of currently used herbicides, which might alter the agro-environmental footprint from crop production. To test this hypothesis, the environmental impact of various herbicide regimes currently used with non-GMHR maize in Belgium was calculated and compared with that of possible herbicide regimes applied in GMHR maize. Impacts on human health and the environment were calculated through the pesticide occupational and environmental risk (POCER) indicator. Results showed that the environmental impact of herbicide regimes solely relying on the active ingredients glyphosate (GLY) or glufosinate-ammonium (GLU) is lower than that of herbicide regimes applied in non-GMHR maize. Due to the lower potential of GLY and GLU to contaminate ground water and their lower acute toxicity to aquatic organisms, the POCER exceedence factor values for the environment were reduced approximately by a sixth when GLY or GLU is used alone. However, the environmental impact of novel herbicide regimes tested may be underestimated due to the assumption that active ingredients used with GMHR maize would be used alone. Data retrieved from literature suggest that weed control efficacy is increased and resistance development delayed when GLY or GLU is used together with other herbicides in the GMHR system. Due to the partial instead of complete replacement of currently used herbicide regimes, the beneficial environmental impact of novel herbicide regimes might sometimes be reduced or counterbalanced. Despite the high weed control efficacy provided by the biotechnology-based weed management strategy, neither indirect harmful effects on farmland biodiversity through losses in food resources and shelter, nor shifts in weed communities have been demonstrated in GMHR maize yet. However, with the increasing adoption rate of GMHR maize and their associated novel herbicide regimes, this situation is expected to change in the short-term. An erratum to this article can be found at     

Transgenic,transplastomic and other genetically modified plants: a Canadian perspective

Since the mid 1990s, genetically modified (GM) crops have been grown commercially in Canada on a scale that has increased steadily over the years. An intense debate ensued, as elsewhere, and many fears were expressed regarding not only the technology itself but some of the main GM crops being grown. It would seem appropriate at this time to examine how these novel crops compare to crops bred by more traditional means and what impacts these GM crops have had based on experience and not merely on conjecture. To begin, we will put things in a historical perspective and recall how domestication and conventional plant breeding have shaped the crops of today. Then, we will describe briefly the distinctive features of GM plants (obtained so far mainly by nuclear transgenesis) and how these novel crops are regulated in Canada. We will then give two examples of widely grown GM crops in Canada (insect-resistant corn and herbicide-tolerant canola) and examine the main questions that were raised as well as the actual impacts these crops have had on the farm. These examples will help us outline some of the limitations of the current generation of GM plants and, finally, we will try to get a glimpse of the future by examining some recent technical developments in the field of recombinant DNA technologies applied to plant breeding.     

Cellulite treatment: a myth or reality: a prospective randomized, controlled trial of two therapies, endermologie and aminophylline cream

Cellulite is a common phenomenon that particularly affects the thighs and buttocks of women. Little scientific evidence exists to support any of the many advertised treatments for it. A total of 52 of 69 women, who were divided into three groups, completed a 12-week, randomized, controlled trial in which the effectiveness of two different treatments for cellulite was assessed. The patients acted as their own controls. The treatments investigated were twice-daily application of aminophylline cream and twice-weekly treatment with Endermologie ES1. Group 1 (double blind) received aminophylline to one thigh/buttock and a placebo cream to the other. Group 2 (singly blind) received Endermologie to one thigh/buttock. Group 3 received Endermologie to both sides and used the same cream regimen as group 1. Results were assessed subjectively by the patient and by clinical examination and photographic assessment by the surgeon (before and after the trial). Morphologic assessment included body mass index, thigh girth at two points, and thigh fat depth measurement by ultrasound. No statistical difference existed in measurements between legs for any of the treatment groups (paired t test, p > 0.4). The best subjective assessment, by the patients themselves, revealed that only 3 of 35 aminophylline-treated legs and 10 of 35 Endermologie-treated legs had their cellulite appearance improved. The authors do not believe that either of these two treatments is effective in improving the appearance of cellulite.     

Medical fact and ulcer disease: a study in scientific controversy resolution

This study seeks to advance the understanding of controversy resolution in science. I take as a case study conceptualization and treatment of ulcer disease. Analysis of causal accounts and effective treatments illustrate the ways in which competing parallel research programs in medicine embody opposing social, political, and economic forces which are bound to the epistemological dimensions of scientific controversy (e.g., standards of evidence, reference, and inference), and which in turn shift perception of the burden of proof. The analysis illustrates the ways in which (1) medical diagnoses create as much as discover useful distinctions and (2) epistemic and non epistemic values divide scientists into competing research programs, as well as (3) the ways in which these structures often effectively prevent scientific controversy closure.     

Fate of genetically modified maize and conventional rapeseed,and endozoochory in wild boar (Sus scrofa)

Feeding experiments were carried out to investigate the digestive fate of transgenic DNA and novel protein in wild boar applying polymerase chain reaction (PCR) and immunodiagnostic techniques. Furthermore, the dispersal of viable maize and rapeseed (endozoochory) was studied. A diet containing conventional rapeseed, and either genetically modified (GM) maize expressing Cry1Ab protein (Bt176) or non-GM isogenic maize was offered. By conventional and quantitative PCR both chloroplast-specific plant DNA (rubisco) and cry1Ab gene fragments were detected only in gastrointestinal content. Using an enzyme-linked immunosorbent assay (ELISA) positive signals of immunoactive Cry1Ab protein were detected in digesta samples. Analysis of endozoochory showed that excreted maize seeds retain their germination capacity only in extremely rare cases and no intact rapeseed was found in faeces. A possible dispersal of viable seeds by wild boars is highly unlikely.     

Anthropological films and the myth of scientific truths

This article describes, analyzes, and interprets various cultural influences on the representational drawings of young Navajo students, in order to understand their changing cultural viewpoint. The data and drawings were gathered from two elementary art classes in one Navajo public school in northeastern Arizona, as part of an ongoing study. This information is compared to anthropological data gathered on adult Navajo drawings nearly 30 years ago, as well as to some dominant theories on child art. Data reveal students are influenced by Navajo traditional images, classroom teachers’ versions of school art, popular art images, pan‐Indian influences, and peer copying. Results reveal the persistence of traditional nature imagery, the incorporation of similar schemas and color use with mainstream children, a keen ability to render realistic images and space, and the incorporation of those American things that the Navajo regard as “good for them.” Keen drawing abilities appear at a young age among the Navajo because of the high status of the arts, traditional education through observation and demonstration, peer imitation, and male drawing competition.     

Monitoring the occurrence of genetically modified soybean and maize around cultivated fields and at a grain receiving port in Korea

Increased imports of genetically modified (CM) soybean and maize might cause genetic contamination of those crops that are conventionally bred, as well as wild soybeans within Korea. Leaves of maize and both cultivated and wild soybeans were sampled in and near rural fields to detect the presence of transgenes. Roadsides around a major grain port in Incheon were also surveyed to monitor the occurrence of incoming CM soybean and maize. The amplificability of DNA extracted from the collected samples was determined by PCR using soybean- or maize-specific primers: lectin and zein genes, respectively. The presence or absence of transgenes was detected by primer sets for the 35S and nos genes. Transgenes were not found in the cultivated or wild soybean or in the maize collected from cultivated fields. However, we obtained one GM maize plant among seven along the roadsides around Incheon Port. Although the effect of a single GM maize plant would be negligible and would not pose any threat to natural environments, an increase in the import of GM plants might lead to future, unapproved cultivation of GM crops. Therefore, appropriate monitoring is necessary to detect the occurrence of GM plants in areas around grain receiving ports and within agroecosystems.     

Design of a decision support tool for managing coexistence between genetically modified and conventional maize at farm and regional levels

Over the last 15 years, several studies on coexistence have used simulation results of spatially explicit gene flow models. These models predict the adventitious presence (AP) of GM grains in non-GM fields at the landscape scale. However, result uncertainty is not quantified. Moreover, most of the models require an important amount of input data on climate, land use, and crop management practices which might not always be available. A comprehensive Bayesian statistical approach has been implemented in the case of gene flow. This approach makes it possible to inform the decision-maker on AP, whatever the amount of information available in a given situation, to provide information on the uncertainty of the predictions and to model the variability of AP within a field, which helps set up sampling strategies.The resulting decision-support tool (DST) can compute the expected AP and its probability distribution in non-GM maize fields at different times of the growing season and under different management scenarios. Integrated through a web interface, the DST is designed to be operationally helpful for managing coexistence between GM and non-GM maize crops for a wide range of stakeholders from farmers to policy makers.     

转基因抗矮花叶玉米对大白鼠骨髓细胞遗传毒性的影响

以SD大鼠为研究对象,研究了转基因抗矮花叶玉米和常规玉米对大白鼠骨髓细胞微核率与染色体畸变率的影响,以观察该转基因玉米对大白鼠可能产生的遗传毒理效应。实验结果表明：饲喂30%和50%转基因玉米日粮组的大白鼠骨髓细胞微核率和染色体畸变率与饲喂常规玉米相比均没有显著差异,而与阳性对照组之间存在极显著差异,这说明转基因玉米与常规玉米对大白鼠骨髓细胞均无遗传毒性。