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Results for “Organisms, Genetically Modified”

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PubMed1999

Transformation of Escherichia coli with DNA from Saccharomyces cerevisiae cell lysates.

We developed a system to monitor the transfer of heterologous DNA from a genetically manipulated strain of Saccharomyces cerevisiae to Escherichia coli. This system is based on a yeast strain that carries multiple integrated copies of a pUC-derived plasmid. The bacterial sequences are maintained in the yeast genome by selectable markers for lactose utilization. Lysates of the yeast strain were used to transform E. coli. Transfer of DNA was measured by determining the number of ampicillin-resistant E. coli clones. Our results show that transmission of the Amp(r) gene to E. coli by genetic transformation, caused by DNA released from the yeast, occurs at a very low frequency (about 50 transformants per microg of DNA) under optimal conditions (a highly competent host strain and a highly efficient transformation procedure). These results suggest that under natural conditions, spontaneous transmission of chromosomal genes from genetically modified organisms is likely to be rare.

Cell-Free System↗

PubMedDate not supplied

Real-time quantitative polymerase chain reaction methods for four genetically modified maize varieties and maize DNA content in food.

Quantitative detection methods are needed for enforcement of the recently introduced labeling threshold for genetically modified organisms (GMOs) in food ingredients. This labeling threshold, which is set to 1% in the European Union and Switzerland, must be applied to all approved GMOs. Four different varieties of maize are approved in the European Union: the insect-resistant Bt176 maize (Maximizer), Btl 1 maize, Mon810 (YieldGard) maize, and the herbicide-tolerant T25 (Liberty Link) maize. Because the labeling must be considered individually for each ingredient, a quantitation system for the endogenous maize content is needed in addition to the GMO-specific detection systems. Quantitative real-time polymerase chain reaction detection methods were developed for the 4 approved genetically modified maize varieties and for an endogenous maize (invertase) gene system.

DNA, Plant↗

PubMed2005

Understanding of genetic information in higher secondary students in northeast India and the implications for genetics education.

Since the work of Watson and Crick in the mid-1950s, the science of genetics has become increasingly molecular. The development of recombinant DNA technologies by the agricultural and pharmaceutical industries led to the introduction of genetically modified organisms (GMOs). By the end of the twentieth century, reports of animal cloning and recent completion of the Human Genome Project (HGP), as well techniques developed for DNA fingerprinting, gene therapy and others, raised important ethical and social issues about the applications of such technologies. For citizens to understand these issues, appropriate genetics education is needed in schools. A good foundation in genetics also requires knowledge and understanding of topics such as structure and function of cells, cell division, and reproduction. Studies at the international level report poor understanding by students of genetics and genetic technologies, with widespread misconceptions at various levels. Similar studies were nearly absent in India. In this study, I examine Indian higher secondary students' understanding of genetic information related to cells and transmission of genetic information during reproduction. Although preliminary in nature, the results provide cause for concern over the status of genetics education in India. The nature of students' conceptual understandings and possible reasons for the observed lack of understanding are discussed.

Cells↗

PubMed1985

Potential food safety problems in genetic engineering.

The rapid development of gene technology, exemplified by the recombinant DNA technique and the hybridoma technique, will heavily influence our food supply in the years to come. Fermentation products from genetic-engineered microbials, the microbials themselves and new plant products will create a number of questions concerning the possible pathogenicity, toxicity, and changed nutritional values of such foodstuffs. This is a great challenge not only to the development of new approaches in nutritional toxicology but also to international cooperation in the field because genetic-modified organisms are not expected to recognize human-made trade barriers or borders. Therefore the initiative of OECD establishing an ad hoc group on safety and regulations in biotechnology is greatly acknowledged.

DNA, Recombinant↗

PubMed2005

Viral promoters can initiate expression of toxin genes introduced into Escherichia coli.

BACKGROUND: The expression of recombinant proteins in eukaryotic cells requires the fusion of the coding region to a promoter functional in the eukaryotic cell line. Viral promoters are very often used for this purpose. The preceding cloning procedures are usually performed in Escherichia coli and it is therefore of interest if the foreign promoter results in an expression of the gene in bacteria. In the case molecules toxic for humans are to be expressed, this knowledge is indispensable for the specification of safety measures. RESULTS: We selected five frequently used viral promoters and quantified their activity in E. coli with a reporter system. Only the promoter from the thymidine kinase gene from HSV1 showed no activity, while the polyhedrin promoter from baculovirus, the early immediate CMV promoter, the early SV40 promoter and the 5' LTR promoter from HIV-1 directed gene expression in E. coli. The determination of transcription start sites in the immediate early CMV promoter and the polyhedrin promoter confirmed the existence of bacterial -10 and -35 consensus sequences. The importance of this heterologous gene expression for safety considerations was further supported by analysing fusions between the aforementioned promoters and a promoter-less cytotoxin gene. CONCLUSION: According to our results a high percentage of viral promoters have the ability of initiating gene expression in E. coli. The degree of such heterologous gene expression can be sufficient for the expression of toxin genes and must therefore be considered when defining safety measures for the handling of corresponding genetically modified organisms.

Bacterial Proteins↗

PubMed2006

New measures of insecticidal efficacy and safety obtained with the 39K promoter of a recombinant baculovirus.

Baculoviruses are orally infectious to insects and considered to be natural insecticides. To enhance their speed-of-kill these viruses were engineered to express arthropod neurotoxins under the control of various strong promoters. Although this strategy proved to be efficient, it raised recently concerns about safety. We analyzed the speed-of-kill and safety of Autographa californica multiple nucleopolyhedrovirus expressing the insecticidal scorpion neurotoxin AaIT and found that the mortality of Helicoverpa armigera larvae was enhanced significantly when the expression was controlled by the baculovirus delayed-early promoter 39K rather than the very late promoter p10. This improvement was also reflected in better protection of cotton leaves on which these insects were fed. Using lacZ as a sensitive reporter we also found that expression driven by the 39K promoter was detected in insect but not in mammalian cells. These results imply that by selection of an appropriate viral promoter, engineered baculoviruses may comply with the high standard biosafety requirements from a genetically modified organism (GMO). Our results provide further support for the potential use of engineered baculoviruses in insect pest control in a safely manner.

Animals↗

PubMed2000

Development of a genetically modified bacteriophage for use in tracing sources of pollution.

Bacteriophage are frequently used as biotracers to identify the source of water pollutants. Genetic manipulation of bacteriophage M13mp18 has been used to enhance this technique by creating a library in which each recombinant bacteriophage genome contains a unique identification sequence. Techniques that identify a recombinant bacteriophage by the presence of the identification sequence, including polymerase chain reaction, restriction site polymorphism and plaque hybridization, have been developed. Recombinant bacteriophage can be used to test a large number of suspected sources simultaneously. The identification sequence also eliminates confusion with natural bacteriophage present in water samples. The performance of the modified bacteriophage and the techniques were assessed in simulated field trials on a restricted site carried out under a consent for environmental release of a genetically modified organism. The techniques were also field tested at sites in northwest England using wild-type M13 bacteriophage.

Bacteriophage M13↗

PubMed2001

The impact of flow rate (simulated leaching) on plasmid transfer frequency between bacteria in a model rhizosphere system.

AIMS: To investigate the effect of flow rate and inoculation order on plasmid transfer frequency between bacteria in a model rhizosphere system. METHODS AND RESULTS: A physical model system was constructed and used to demonstrate that although flow rate did affect plasmid transfer frequency for an introduced strain, the flow rates necessary for a significant effect on an established population were much higher than typical water flow rates found through soil. Plasmid transfer frequency was highly sensitive to strain inoculation order. CONCLUSION: Flow rate may not have a significant effect on plasmid transfer frequency between established bacterial populations in the rhizosphere. SIGNIFICANCE AND IMPACT OF THE STUDY: This study contributes to the current debate over the release and spread of genetically modified organisms into the environment. It also demonstrates that model controlled systems may be used to rapidly obtain initial data about the potential behaviour of microorganisms, prior to more costly and lengthy glasshouse and field trials.

Conjugation, Genetic↗

PubMed2001

[Genetically engineered drugs and their application with the example of erythropoietin].

Over the past two decades, many genetically engineered drugs have been developed and approved for the treatment of patients. Typically, these drugs are characterized by a high and specific activity in the presence of optimal safety. They include hormones, enzymes, growth and coagulation factors, antibodies as well as vaccines. All these proteins are generated using recombinant DNA technology. An expression vector with the gene encoding for the protein of interest is introduced into an appropriate microorganism or cell line. The biochemical machinery of the host cell then translates the genetic information into the corresponding protein. Large scale production of the recombinant drugs uses biotechnological processes. The genetically modified organisms are grown in bioreactors from which the desired protein is finally isolated and purified. This review focuses on the production and clinical application of recombinant erythropoietin in the areas of nephrology, hemato-oncology and elective surgery.

Biotechnology↗

PubMed2001

Contribution of European research to risk analysis.

The European Commission's, Quality of Life Research Programme, Key Action 1-Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety, of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches, harmonization of risk assessment principles methodologies and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries, to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women, evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.

Diet↗

PubMedDate not supplied

Detection of genetic modification in cured tobacco leaf: proficiency testing using polymerase chain reaction-based methods.

The Cooperation Centre for Scientific Research Relative to Tobacco (CORESTA; Paris, France) "Task Force Genetically Modified Tobacco-Detection Methods" investigated the performance of qualitative and quantitative methods based on the polymerase chain reaction (PCR) for the detection and quantitation of genetically modified (GM) tobacco. In the 4 successful rounds of proficiency testing, the cauliflower mosaic virus 35S RNA promoter (CaMV 35S) and the Agrobacterium tumefaciens nopaline synthase terminator (NOS) were selected as target sequences. Blind-coded reference materials containing from 0.1 to 5.0% and from 0.15 to 4% GM tobacco were used in 2 rounds of qualitative and quantitative PCR, respectively. Eighteen laboratories from 10 countries participated in this study. Considering all methods and 2 rounds, the different laboratories were able to detect GM tobacco at the 0.1% level in 46 out of 58 tests in qualitative assays. The results of the proficiency test indicate that both end point screening and real-time quantitative methods are suitable for the detection of genetically modified organisms in tobacco leaf samples having a GM content of 0.1% or higher. The CORESTA proficiency study represents a first step towards the interlaboratory evaluation of accuracy and precision of PCR-based GM tobacco detection, which may lead to the harmonization of analytical procedures and to the enhancement of comparability of testing results produced by different laboratories.

Agrobacterium tumefaciens↗

PubMed2003

In vivo studies on possible health consequences of genetically modified food and feed--with particular regard to ingredients consisting of genetically modified plant materials.

This synopsis reviews published in vivo studies on possible health consequences of genetically modified food and feed where the ingredients in question have consisted of genetically modified plant materials. The following, however, have not been taken into consideration:--ingredients consisting of genetically modified microorganisms or parts of animals/fish--ingredients produced by/from genetically modified organisms but without any DNA present--studies on consequences for the environment or biodiversity--in vitro studies or computer simulations. According to a Norwegian report "Gen-mat" (NOU 2000:29), and a more recent search in Medline and Citations Index, to our knowledge a total of ten studies have been published on the health effects of GM-foods and feeds. In this minireview the data made available in these published studies is discussed.

Animal Feed↗

PubMed2001

The future of transgenic plants in developing countries.

Whatever their own policies may be, developing countries will inevitably be affected by the development of genetically-modified organisms in industrialized countries. While maintaining a cautious attitude, most of these countries wish to keep their options open, thus protecting themselves from the risk of being deprived of future technologies that might allow them to achieve self-sufficiency in food production, to resolve certain problems confronting their most vulnerable populations and to preserve the international competitiveness of their products. Companies should see that it is in their interest to help these countries implement their own policies, notably through an open attitude to industrial property. If the value of genetic engineering is thus confirmed, then it perhaps in this manner that GMOs will earn the legitimacy required to make them acceptable to the people of Northern countries where the majority of solvent markets are located.

Agriculture↗

PubMed2006

GMOs: building the future on the basis of past experience.

Biosafety of genetically modified organisms (GMOs) and their derivatives is still a major topic in the agenda of government and societies worldwide. The aim of this review is to bring into light that data that supported the decision taken back in 1998 as an exercise to stimulate criticism from the scientific community for upcoming discussions and to avoid emotional and senseless arguments that could jeopardize future development in the field. It must be emphasized that Roundup Ready soybean is just one example of how biotechnology can bring in significant advances for society, not only through increased productivity, but also with beneficial environmental impact, thereby allowing more rational use of agricultural pesticides for improvement of the soil conditions. The adoption of agricultural practices with higher yield will also allow better distribution of income among small farmers. New species of genetically modified plants will soon be available and society should be capable of making decisions in an objective and well-informed manner, through collegiate bodies that are qualified in all aspects of biosafety and environmental impact.

3-Phosphoshikimate 1-Carboxyvinyltransferase↗

PubMedDate not supplied

Validation studies and proficiency testing.

Genetically modified organisms (GMOs) entered the European food market in 1996. Current legislation demands the labeling of food products if they contain <1% GMO, as assessed for each ingredient of the product. To create confidence in the testing methods and to complement enforcement requirements, there is an urgent need for internationally validated methods, which could serve as reference methods. To date, several methods have been submitted to validation trials at an international level; approaches now exist that can be used in different circumstances and for different food matrixes. Moreover, the requirement for the formal validation of methods is clearly accepted; several national and international bodies are active in organizing studies. Further validation studies, especially on the quantitative polymerase chain reaction methods, need to be performed to cover the rising demand for new extraction methods and other background matrixes, as well as for novel GMO constructs.

Calibration↗

PubMed2003

Postmodernism for animal scientists.

Many scientists regard the term "postmodernism" as controversial. Because postmodern theorists question whether science can be objective, some scientists view postmodernism as anti-scientific. In this paper, we argue that traditional accounts of science developed during the modern era (16th, 17th, and 18th centuries) are still influential in animal science, but are no longer plausible. In particular, the view that science automatically leads to human betterment seems to be disingenuous. A postmodern view that portrays science as a political activity seems more plausible, and offers a means to better understand contentious policy issues that involve science. Although most animal scientists accept the view that theory selection, experimental designs, and technology development require value-laden judgments, most fail to recognize that such values may be politically motivated and embrace prevailing political structures. Postmodernists such as Michel Foucault argue that through the generation of knowledge, scientific disciplines create a discourse that serves to maintain a particular social structure that has political implications. Viewed in this way, it becomes clear how various interest groups can be critical of certain scientific programs. For example, groups that oppose research dealing with cloning, genetically modified organisms, and intensive livestock production may not be as much opposed to science as they are to the political interests served by this science. In other words, such groups view these research agendas as promoting policies that place them at risk. Such a postmodern account of science, may help animal scientists better understand the nature of contentious issues, and provide a basis for reforming the animal science discipline in ways that make it more responsive to the diverse interests of a pluralistic society.

Animal Husbandry↗

PubMed2001

Genetically modified feeds in animal nutrition. 1st communication: Bacillus thuringiensis (Bt) corn in poultry, pig and ruminant nutrition.

During the last few years, animal nutrition has been confronted with genetically modified organisms (GMO), and their significance will increase in the future. The study presents investigations on the substantial equivalence of the transgenic Bt (Bacillus thuringiensis) corn and the corresponding nontransgenic hybrid Cesar and parameters of nutrition physiology such as digestibility and energy content for poultry, pigs and ruminants. The results of the analysed corn samples as well as of the silage samples illustrated substantial equivalence in all investigated ingredients, such as crude nutrients, amino acids, fatty acids, minerals and non-starch polysaccharides. The results of the experiments using poultry, pigs, wethers and fattening bulls were not influenced by the genetic modification of corn. The determined values for the digestibilities and the energy contents for poultry, pigs and wethers were not affected by the used corn variety. Neither the examined parameters of the fattening experiments with bulls nor the slaughter results showed any significant differences between the bulls fed on silages made from the nontransgenic or transgenic corn.

Animal Feed↗

PubMed2006

Qualitative and quantitative polymerase chain reaction analysis for genetically modified maize MON863.

Qualitative and quantitative analytical methods were developed for the new event of genetically modified (GM) maize, MON863. One specific primer pair was designed for the qualitative polymerase chain reaction (PCR) method. The specificity and sensitivity of the designed primers were confirmed. PCR was performed on genomic DNAs extracted from MON863, other GM events, and cereal crops. Single PCR product was obtained from MON863 by the designed primer pair. Eight test samples including GM maize MON863 were prepared at 0.01 approximately 10% levels and analyzed by PCR. Limit of detection of the method was 0.01% for GM maize MON863. On the other hand, another specific primer pair and probe were also designed for quantitative method using a real-time polymerase chain reaction. As a reference molecule, a plasmid was constructed from a taxon-specific DNA sequence for maize, a universal sequence for a cauliflower mosaic virus (CaMV) 35S promoter used in most genetically modified organisms, and a construct-specific DNA sequence for the MON863 event. Six test samples of 0.1, 0.5, 1.0, 3.0, 5.0 and 10.0% of GM maize MON863 were quantitated for the validation of this method. At the 3.0% level, the bias (mean vs true value) for MON863 was 3.0%, and its relative standard deviation was 5.5%. Limit of quantitation of the method was 0.5%. These results show that the developed PCR methods can be used to qualitatively and quantitatively detect GM maize MON863.

DNA Primers↗