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PubMed1999

[Food additives and genetically modified food--a risk for allergic patients?].

Adverse reactions to food and food additives must be classified according to pathogenic criteria. It is necessary to strictly differentiate between an allergy, triggered by a substance-specific immunological mechanism, and an intolerance, in which no specific immune reaction can be established. In contrast to views expressed in the media, by laymen and patients, adverse reactions to additives are less frequent than is believed. Due to frequently "alternative" methods of examination, an allergy to food additives is often wrongly blamed as the cause of a wide variety of symptoms and illness. Diagnosing an allergy or intolerance to additives normally involves carrying out double-blind, placebo-controlled oral provocation tests with food additives. Allergic reactions to food additives occur particularly against additives which are organic in origin. In principle, it is possible that during the manufacture of genetically modified plants and food, proteins are transferred which potentially create allergies. However, legislation exists both in the USA (Federal Drug Administration, FDA) and in Switzerland (Ordinance on the approval process for GM food, GM food additives and GM accessory agents for processing) which require a careful analysis before a genetically modified product is launched, particularly where foreign genes are introduced. Products containing genetically modified organisms (GMO) as additives must be declared. In addition, the source of the foreign protein must be identified. The "Round-up ready" (RR) soya flour introduced in Switzerland is no different from natural soya flour in terms of its allergenic potential. Genetically modified food can be a blessing for allergic individuals if gene technology were to succeed in removing the allergen (e.g. such possibilities exist for rice). The same caution shown towards genetically modified food might also be advisable for foreign food in our diet. Luckily, the immune system of the digestive tract in healthy people tolerates foreign antigens. Food allergies in adults occur mainly among those allergic to pollen.

Adult↗
PubMed2005

Regulations governing veterinary medicinal products containing genetically modified organisms in the European community.

This paper describes particular aspects of the marketing of veterinary medicinal products (VMPs) that contain or consist of genetically modified micro-organisms (GMMs) or genetically modified organisms (GMOs). The regulatory requirements and the procedures applied in the European Union for each phase (pre-marketing, authorisation process, and post-authorisation labelling and monitoring) are explained. In most cases VMPs are subject to both pharmaceutical and GMO regulations. In the early stages of the process, before applications for marketing authorisation are submitted, the assessment of clinical trials and experiments in contained areas is principally the responsibility of national authorities. However, the marketing of all VMPs containing or consisting of GMOs must be authorised at European level, although the national authorities are informed and involved in the assessment process.

Animals↗
PubMed2003

Biological containment of genetically modified Lactococcus lactis for intestinal delivery of human interleukin 10.

Genetically modified Lactococcus lactis secreting interleukin 10 provides a therapeutic approach for inflammatory bowel disease. However, the release of such genetically modified organisms through clinical use raises safety concerns. In an effort to address this problem, we replaced the thymidylate synthase gene thyA of L. lactis with a synthetic human IL10 gene. This thyA- hIL10+ L. lactis strain produced human IL-10 (hIL-10), and when deprived of thymidine or thymine, its viability dropped by several orders of magnitude, essentially preventing its accumulation in the environment. The biological containment system and the bacterium's capacity to secrete hIL-10 were validated in vivo in pigs. Our approach is a promising one for transgene containment because, in the unlikely event that the engineered L. lactis strain acquired an intact thyA gene from a donor such as L. lactis subsp. cremoris, the transgene would be eliminated from the genome.

Amino Acid Sequence↗
PubMed2000

Enhancement of antitumor immunity against B16 melanoma tumor using genetically modified dendritic cells to produce cytokines.

Dendritic cells (DC) that have been genetically modified to express cytokine genes may be novel tools for inducing antitumor immune responses. In the present study, the pMX retroviral vector was modified to express the mouse IL-2 (mIL-2pMX) and mouse IL-12 (mIL-12pMX) genes. Supernatants from 293 cells transfected with pMX retroviral vectors were harvested and used to transduce mouse lin- bone marrow (BM) progenitor cells. After 48 h co-culture with pseudotype retrovirus, BM cells were cultured for 12 days in the presence of mGM-CSF, mSCF and mTNF-alpha to obtain a DC-enriched fraction. Flow cytometric analysis showed that GFP protein expression in these cultures was 20-40% and that 40-50% of the cultured BM cells were positive for the DC marker, DEC205. About 60% of cells sorted for DEC205 also expressed GFP. The supernatants of DC-mIL-2 and DC-mIL-12 cultured for 48 h contained 5.2 +/- 0.15 and 33.9 +/- 2.6 ng cytokine protein per milliliter, respectively. Intratumoral injection of DC-mIL-2 or DC-mIL-12 on days 8 and 15 after the intradermal injection of 1 x 105 B16F10 cells, resulted in a significant reduction in tumor size by day 21, as compared with mice treated with unmodified DC or DC-GFP. Longer term analysis as assessed at day 42 revealed that B16 tumor-bearing mice treated with cytokine gene-modified DC survived significantly longer than mice from other groups. Spleen cells obtained from DC-treated mice were specifically sensitized for the generation of CTL by subsequent restimulation with gene-modified DC. These results suggested that DC genetically modified to express IL-2 or IL-12 can induce potent antitumor responses against well-established, poorly immunogenic B16F10 tumors. Gene Therapy (2000) 7, 2113-2121.

Animals↗
PubMed2004

In vivo selection of genetically modified erythroid cells using a jak2-based cell growth switch.

Cell-based therapies have potential widespread applications in clinical medicine, and methods for controlling the fate of transplanted cells are needed. We have previously described a means for directing the growth of genetically modified cells in vivo using a derivative of the thrombopoietin receptor, mpl, that is reversibly activated by a drug called a chemical inducer of dimerization (CID). Since Jak2 participates in signaling from a number of different cytokine receptors (including mpl), we tested whether direct activation of the JH1 domain of Jak2 would broaden the repertoire of hematopoietic lineages responsive to the CID. While the engineered Jak2 induced a significant rise in genetically modified red cells, as we have observed previously with mpl, it lacked mpl's ability to expand genetically modified platelets and failed to expand genetically modified granulocytes, B cells, or T cells. These findings identify a signaling molecule other than mpl that can function as a cell growth switch in vivo and demonstrate that signaling molecules used for in vivo selection need not be confined to receptors. The erythroid-restricted growth response suggests that CID-activated Jak2 may be well suited to gene therapy applications in sickle cell anemia or beta-thalassemia.

Animals↗
PubMed2005

[Detection of genetically modified organisms in food and animal feed by polymerase chain reaction].

OBJECTIVE: To investigate the presence of genetically modified organisms (GMO) in the foods and animal feed samples in Guangzhou market. METHODS: The presence of GMO were investigated by PCR detection of camv 35S promoter and nos terminator, and the presence of RoundUp Ready Soybean (RRS), Bt176 Maximaizer or Mon810 YieldGard in GMO-positive samples were further determined by PCR detecting their specific DNA fragments respectively. RESULTS: One corn soup sample, two soybean samples, one potato fries sample as well as two animal feed samples were revealed to be GMO-positive in twenty-two food samples and three animal feed samples, and the presence of RRS in the GMO-positive soybean samples and the two positive animal feed samples were verified by PCR detection of a 129 bp RRS-specific DNA fragment, however, no Bt176 Maximaizer or Mon810 YieldGard specific PCR products were obtained with the GMO-positive corn soup and animal feed DNA samples used as PCR templates. CONCLUSION: Genetically modified organism presented in foods and animal feeds even though they were not been labelled.

Animal Feed↗
PubMed2002

Between myth and reality: genetically modified maize, an example of a sizeable scientific controversy.

Maize is a major crop plant with essential agronomical interests and a model plant for genetic studies. With the development of plant genetic engineering technology, many transgenic strains of this monocotyledonous plant have been produced over the past decade. In particular, field-cultivated insect-resistant Bt-maize hybrids are at the centre of an intense debate between scientists and organizations recalcitrant to genetically modified organisms (GMOs). This debate, which addresses both safety and ethical aspects, has raised questions about the impact of genetically modified (GM) crops on the biodiversity of traditional landraces and on the environment. Here, we review some of the key points of maize genetic history as well as the methods used to stably transform this cereal. We describe the genetically engineered Bt-maizes available for field cultivation and we investigate the controversial reports on their impacts on non-target insects such as the monarch butterfly and on the flow of transgenes into Mexican maize landraces.

Animals↗
PubMed2002

Biosensor technology and surface plasmon resonance for real-time detection of genetically modified Roundup Ready soybean gene sequences.

Biospecific interaction analysis (BIA) was performed using surface plasmon resonance (SPR) and biosensor technologies to detect genetically modified Roundup Ready soybean gene sequences. We first immobilized, on SA sensor chips, single-stranded biotinylated oligonucleotides containing soybean lectin and Roundup Ready gene sequences, and the efficiency of hybridization to oligonucleotide probes differing in length was determined. Second, we immobilized biotinylated PCR products from nontransgenic soybeans (genomes carrying only the lectin gene), as well as from genetically modified Roundup Ready soybean, and we injected the oligonucleotide probes. Furthermore, we used the sensor chips carrying either lectin and Roundup Ready soybean PCR products or 21-mer oligonucleotide as probes, and we injected both nonpurified and purified asymmetric PCR products. The results obtained show that 13 and 15 mer oligonucleotides are suitable probes to detect genetically modified Roundup Ready soybean gene sequences (either target oligonucleotides or PCR products) under standard BIA experimental conditions. By contrast, when 11 mer DNA probes were employed, no efficient hybridization was obtained. All the SPR-based formats were found to be useful for detection of Roundup Ready gene sequences, suggesting that these procedures are useful for the real-time monitoring of hybridization between target single-stranded PCR products, obtained by using as substrates DNA isolated from normal or transgenic soybeans, and oligonucleotide or PCR-generated probes, therefore enabling a one-step, nonradioactive protocol to perform detection.

Biosensing Techniques↗
PubMed2002

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.

Agriculture↗
PubMed2004

Encapsulated, genetically modified cells producing in vivo therapeutics.

The ability to implant genetically modified cells in immuno-isolating materials has much potential for therapeutic use. This review presents the different types of polymer that can be used for encapsulation of cells and the recent use of genetically modified, encapsulated and thus immunoprotected cells for the treatment of diseases in animal models and clinical trials. Some of the challenges faced by these technologies and potential solutions are also discussed.

Animals↗
PubMed1997

Survival of grafts of genetically modified cardiac myocytes transfected with FITC-labeled oligodeoxynucleotides and the beta-galactosidase gene in the noninfarcted area, but not the myocardial infarcted area.

Since one of the attractions of gene therapy in the heart is the implantation of genetically modified cultured cells, we employed genetically modified myocytes transfected with FITC-labeled oligodeoxynucleotides (ODN) and beta-galactosidase gene in this study, to investigate the cellular localization and fate of grafted myocytes in the heart. In addition, we examined the feasibility of myocytes grafting into a myocardial infarction model. Delivery of FITC-labeled ODN with the HVJ-liposome method resulted in sustained fluorescence as compared to direct transfer of 'naked' ODN. Interestingly, implantation of cardiac myocytes transfected with FITC-labeled ODN ex vivo by the HVJ-liposome method resulted in sustained fluorescence for at least 1 week in the noninfarcted area, whereas little fluorescence was detected in the area of infarction. This observation was confirmed by measurement of fluorescence, which showed significantly higher levels in the noninfarcted area than the infarcted area. Positive staining for beta-galactosidase protein was also clearly observed 7 days after grafting of transfection of the beta-galactosidase gene, while no staining was detected in grafted myocytes in control rats. Survival of implanted genetically modified cardiac myocytes in the noninfarcted, but not infarcted area, provides new information for the local delivery of recombinant molecules to the heart using gene therapy.

Animals↗
PubMed2004

A histochemical method using a substrate of beta-glucuronidase for detection of genetically modified papaya.

A histochemical assay for detecting genetically modified (GM) papaya (derived from Line 55-1) is described. GM papaya, currently undergoing a safety assessment in Japan, was developed using a construct that included a beta-glucuronidase (GUS) reporter gene linked to a virus coat protein (CP) gene. Histochemical assay was used to visualize the blue GUS reaction product from transgenic seed embryos. Twelve embryos per fruit were extracted from the papaya seeds using a surgical knife. The embryos were incubated with the substrate 5-bromo-4-chloro-3-indolyl-beta-D-glucuronide (X-Gluc) in a 96-well microtiter plate for 10-15 hours at 37 degrees C. Seventy-five percent of GM papaya embryos should turn blue theoretically. The histochemical assay results were completely consistent with those from a qualitative polymerase chain reaction (PCR) method developed by this laboratory. Furthermore, the method was validated in a five-laboratory study. The method for detection of GM papaya is rapid and simple, and does not require use of specialized equipment.

Carica↗
PubMed2004

New qualitative detection methods of genetically modified potatoes.

In Japan, 8 lines of genetically modified (GM) potato (2 lines of NewLeaf potato; NL, 3 lines of NewLeaf Plus potato; NLP, and 3 lines of NewLeaf Y potato; NLY) have already been authorized as safe for use in foods and feeds. We have developed polymerase chain reaction (PCR) methods for the qualitative detection of the GM potatoes for the screening and the identification of NL, NLP and NLY. The gene encoding uridine diphosphate (UDP)-glucose pyrophosphorylase (UGPase) was used as a taxon specific gene. We designed the primer pair to detect the cryIIIA genes as a screening method for GM potatoes because the gene should be inserted in all 8 lines of the GM potatoes. For identification of NL, NLP and NLY, we further designed three specific primer pairs for the different recombinant DNAs (r-DNA) specifically introduced into NL, NLP, or NLY. In addition, to identify the 3 lines of NLY that have been introduced with the same r-DNA, the three line-specific primer pairs for the border sequence between the r-DNA and genomic DNA of NLY 3 lines were designed. Six lines of GM potato used as the test material were specifically identified using the each primer pair under the same PCR condition. The detection limits of all the GM potatoes should be approximately 0.1%. Furthermore, the specificity and reproducibility of the methods were confirmed in a six-laboratory collaborative study.

Bacillus thuringiensis Toxins↗
PubMed2003

Responses of plants and invertebrate trophic groups to contrasting herbicide regimes in the Farm Scale Evaluations of genetically modified herbicide-tolerant crops.

Effects of genetically modified herbicide-tolerant (GMHT) and conventional crop management on invertebrate trophic groups (herbivores, detritivores, pollinators, predators and parasitoids) were compared in beet, maize and spring oilseed rape sites throughout the UK. These trophic groups were influenced by season, crop species and GMHT management. Many groups increased twofold to fivefold in abundance between early and late summer, and differed up to 10-fold between crop species. GMHT management superimposed relatively small (less than twofold), but consistent, shifts in plant and insect abundance, the extent and direction of these effects being dependent on the relative efficacies of comparable conventional herbicide regimes. In general, the biomass of weeds was reduced under GMHT management in beet and spring oilseed rape and increased in maize compared with conventional treatments. This change in resource availability had knock-on effects on higher trophic levels except in spring oilseed rape where herbivore resource was greatest. Herbivores, pollinators and natural enemies changed in abundance in the same directions as their resources, and detritivores increased in abundance under GMHT management across all crops. The result of the later herbicide application in GMHT treatments was a shift in resource from the herbivore food web to the detritivore food web. The Farm Scale Evaluations have demonstrated over 3 years and throughout the UK that herbivores, detritivores and many of their predators and parasitoids in arable systems are sensitive to the changes in weed communities that result from the introduction of new herbicide regimes.

Agriculture↗
PubMed2005

[Rapid analysis of genetically modified soybean by a duplex PCR-capillary electrophoresis system with laser-induced fluorescence detection].

OBJECTIVE: To develop a rapid detection method for genetically modified soybean resistant to glyphosate. METHODS: A duplex PCR was performed with primers designed in this study to simultaneously amplify heterogenous genes in transgenic soybean: CaMV-35S promoter, NOS terminator and CP4-EPSPS gene. And a simple capillary electrophoresis with laser-induced fluorescence detection (CE-LIF) was developed and applied to the rapid analysis of the above PCR products by using a 50 cm length x 100 microm i.d. capillary coated with linear polyacrylamide and an 8 g/L HPMC-4000 sieving buffer under 200 V/cm electric field strength. RESULTS: The proposed method was able to simultaneously detect the three heterogenous genes existing in genetically modified soybean under the optimization conditions of PCR and capillary electrophoresis. The measured sequences of the duplex PCR products were identical with the original genes' sequences. Moreover, the sample volumes required were not more than 5 nl and the detection could be completed in less than 24 min. The relative standard deviations (R. S. D.) of the migration times for the PCR products were < or = 3.2%. CONCLUSION: In comparison with agarose gels electrophoresis, the duplex PCR-based capillary electrophoretic method with laser-induced fluorescence detection is rapid, sensitive and accurate, and it is suitable for detection of genetically modified soybean.

DNA, Plant↗
PubMed2005

Multigeneration reproductive and developmental toxicity study of bar gene inserted into genetically modified potato on rats.

Each specific protein has an individual gene encoding it, and a foreign gene introduced to a plant can be used to synthesize a new protein. The identification of potential reproductive and developmental toxicity from novel proteins produced by genetically modified (GM) crops is a difficult task. A science-based risk assessment is needed in order to use GM crops as a conventional foodstuff. In this study, the specific characteristics of GM food and low-level chronic exposure were examined using a five-generation animal study. In each generation, rats were fed a solid pellet containing 5% GM potato and non-GM potato for 10 wk prior to mating in order to assess the potential reproductive and developmental toxic effects. In the multigeneration animal study, there were no GM potato-related changes in body weight, food consumption, reproductive performance, and organ weight. Polymerase chain reaction (PCR) was carried out using extracted genomic DNA to examine the possibility of gene persistence in the organ tissues after a long-term exposure to low levels of GM feed. In each generation, the gene responsible for bar was not found in any of the reproductive organs of the GM potato-treated male and female rats, and the litter-related indexes did not show any genetically modified organism (GMO)-related changes. The results suggest that genetically modified crops have no adverse effects on the multigeneration reproductive-developmental ability.

Animals↗
PubMedDate not supplied

[Detection of genetically modified soy (Roundup-Ready) in processed food products].

In this study, the application of a qualitative and a quantitative method of analysis to detect genetically modified RR-Soy (Roundup-Ready Soy) in processed foods is described. A total of 179 various products containing soy such as baby food and diet products, soy drinks and desserts, tofu and tofu products, soy based meat substitutes, soy protein, breads, flour, granules, cereals, noodles, soy bean sprouts, fats and oils as well as condiments were investigated following the pattern of the section 35 LMBG-method L 23.01.22-1. The DNA was extracted from the samples and analysed using a soybean specific lectin gene PCR as well as a PCR, specific for the genetic modification. Additional, by means of PCR in combination with fluorescence-detection (TaqMan 5'-Nuclease Assay), suspicious samples were subjected to a real-time quantification of the percentage of genetically modified RR-Soy. The methods of analysis proved to be extremely sensitive and specific in regard to the food groups checked. The fats and oils, as well as the condiments were the exceptions in which amplifiable soy DNA could not be detected. The genetic modification of RR-Soy was detected in 34 samples. Eight of these samples contained more than 1% of RR-Soy. It is necessary to determine the percentage of transgenic soy in order to assess whether genetically modified ingredients were deliberately added, or whether they were caused by technically unavoidable contamination (for example during transportation and processing).

Beverages↗
PubMed2003

Bone regeneration through transplantation of genetically modified cells.

To the author's knowledge, the rabbit is the largest animal model used to explore bone regeneration with genetically modified cells. This technology needs to be expanded to larger animal models that represent a more clinically relevant application in which cells are isolated from the animal, expanded ex vivo, genetically modified, and implanted in a critical-size bone defect in the donor animal. Furthermore, optimization of the vector type, vector dose, cell dose, and carrier material choice must be accomplished in animal models before clinical investigation is initiated. Most research has focused on a single osteoinductive protein; however, multiple proteins may synergize to further enhance bone formation. In conclusion, transplantation of genetically modified cells provides a new opportunity to improve bone tissue regeneration.

Animals↗