ecostory 55-2005
Mice got ill - trials with genetically engineered peas stopped - Deutsch français
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Mice got ill - trials with genetically engineered peas stopped


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For ten years Australian researchers cultivated genetically engineered peas and then fed these peas for trial purposes to mice. This trial had to be stopped now since the mice developed lung disease. The genetically engineeredpeas could have caused the illness, the researchers suspect. Science writer Hans-Stefan Rüfenacht explains a complex situation.

In these trials peas were genetically engineered so as to make them resistant to an important ... ... ... Schädling, den gemeinen Erbsenkäfer. Den Erbsen pflanzte man dafür ein Gen ein, das aus einer Bohne stammt. Dieses Gen ist verantwortlich für ein bestimmtes Eiweiss, das seinerseits den Abbau von Stärke blockiert. Der Erbsenschädling, der Käfer, der nun auf sein Futter, die Erbsen trifft, kommt in Kontakt mit diesem Eiweiss, das eben den Stärkeabbau hemmt, ergo, die Käferlarven können ihre Nahrung, die Stärke, nicht mehr abbauen und verhungern.

So weit, so gut

In weiteren Experimenten stellten die australischen Forscher nun aber eine unerwünschte Nebenwirkung fest. Verfütterte man die gentechnisch veränderten Erbsen an Feldmäuse, dann entwickelten diese Tiere eine Lungenkrankheit in Zusammenhang mit Immunproblemen. Die Mäuse hätten aber keine lebensbedrohliche Reaktion gezeigt, sagen die Forscher weiter.

Interessant war dabei aber, fütterte man die Mäuse mit Bohnen, aus denen das Schädlingsschutzgen ursprünglich stammte, dann zeigten die Mäuse keine Nebenwirkungen. Die Forscher fanden dann heraus, dass die unerwünschten Wirkungen damit zudammenhingen, dass man das Gen aus der Bohne in die Erbse übertragen hatte. Dort, in der Erbse, führte das Gen zu einem Eiweiss, das etwas anders aufgebaut war als in der Bohne. Dem Eiweiss wurde in der Erbse bestimmte Zuckermolekule zusätzlich angehängt, was zu einem Eiweiss führte mit den eben unerwünschten Wirkungen.

Diese Mäuseexperimente bedeuten allerdings noch nicht, dass in anderen Tieren oder sogar in Menschen solche Nebenwirkungen auftreten müssen, wenn etwa ein Mensch derart gentechnisch veränderte Erbsen essen würde. Aber ausgeschlossen ist das auch nicht. Weitere Experimente wären dazu notwendig.

Die Experimente in Mäusen bestätigen aber, wasfrüher selten mal zu beobachten war: Gene, die von einem Spenderorganismus, hier der Bohne, in einen Empfänger, hier die Erbse, übertragen werden, können im neuen Organismus zu Substanzen mit unerwünschter Wirkung führen. Und insofern muss man einen solchen Gentransfer und seine Folgen abklären, vor allem auch dann, wenn der Empfängerorganismus zum Beispiel eine Nutzpflanze ist, de als Lebensmittel dient.

- Hans Stefan Rüfenacht, in Radio DRS1 18.11.2005.
(Transcript & translation : Helmut Lubbers)
ecoglobe: Wir denken an die vielen Gentechbefürworter und sogar Wissenschaftler, die völlig naiv behaupten, gentechnisch veränderte Nahrungsmittel seien bedekenlos weil in den USA Millionen von Menschen schon Jahre lang solche Lebensmittel ohne Schaden essen.
Wir meinen, ohne Kontrollpopulation und Doppelblindstudien, unterteilt nach Alter, Geschlecht und Essensgewohnheiten, in kontrollierter Umgebung, ist eine solche Aussage völlig unwissenschaftlich.

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5n19
http://sg.news.yahoo.com/051118/1/3wm54.html Friday November 18, 10:46 AM Australian researchers scrap GM peas after mice fall ill ADVERTISEMENT AFP Photo Australian researchers have confirmed they have scrapped 10 years of research into genetically modified peas because the altered version caused lung inflammation in mice. The Commonwealth Scientific and Industrial Research Organisation (CSIRO) had been attempting to modify peas so they could resist insect attacks without the use of chemical sprays. It said in a statement that the study was discontinued "because the GM peas did not satisfy all categories of a stringent risk assessment process." The peas, which were almost 100 percent resistant against pea weevil attacks, caused inflammation of lung tissue in mice and other adverse affects, researchers said. "The reaction of the mice to the protein (involved) might reflect something that would happen to humans," deputy chief of CSIRO plant industry T. J. Higgins told ABC radio. "There isn't any evidence that would happen but there is a chance that it could happen." The pea weevil -- known to science as Bruchus pisorum -- can cause yield losses of up to 30 percent a year if left untreated and posed a risk to Australia's 100 million dollar (73 million US) pea industry. Higgins said the work supported the need for a case-by-case examination of plants developed using genetic modification. "Even though this GM field pea research will not be progressed further, the technology is very valuable and we're considering applying it to other research," he said.
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http://www.agbios.com/main.php?action=ShowNewsItem&id=7035 5n20 GM Crop Scrapped As Mice Made Ill Author: Selina Mitchell and Leigh Dayton Publication: The Australian Date: Thursday, November 17, 2005 CSIRO scientists have abandoned a decade-long GM crop project in its last stages of research after learning that peas modified to resist insects had caused inflammation in the lung tissues of mice. It is only the second time in the world a GM project has been abandoned after a gene transfer from one crop to another, deputy chief of CSIRO Plant Industry T.J.Higgins said yesterday. The findings - published in the Journal of Agricultural and Food Chemistry this week - suggest the allergic-style reaction in the mice was triggered because the protein was altered by a natural process. Dr Higgins said it was disappointing to have to discontinue work on the genetically modified field pea, which had proved almost 100 per cent effective against insect attack. But he said the case demonstrated the effectiveness of strict regulations on research into genetically modified crops. The regulations did not allow the commercial release of a genetically modified crop unless it satisfied all health and safety requirements. "It's a good example of why the regulations are necessary," he said. "This work strongly supports the need for case-by-case examination of plants developed using genetic modification and the importance of decision-making based on good science." But Greenpeace GM campaigner Jeremy Tager disagreed. "That's complete nonsense," he said. "Withdrawing a failure doesn't show the success of the regulatory system. "It just shows the failure of the science in relation to this gene product." Director of the GeneEthics Network Bob Phelps was pleased the project was scrapped. "Not only are these experiments on a minor crop a waste of public money, they highlight the growing concern worldwide about the health impacts of all GM foods," Mr Phelps said. The GM peas will be destroyed, Gene Technolgy Regulator Sue Meeks said. "The whole proof-of-concept study will be wrapped up under contained conditions - nothing has entered the human food chain," Dr Meeks said. The CSIRO was working with the Grains Research and Development Corporation to genetically modify peas to resist attack by the pea weevil (Bruchus pisorum) and fungus. Pea weevils alone can cause yield losses of up to 30per cent a year in the $100million-a-year field pea industry. The scientists added a gene that produces a bean protein to the peas that causes weevil larvae to starve. Humans have been eating the naturally occurring bean protein for years. But a team at the John Curtin School of Medical Research found that when mice were fed the GM peas, they suffered an adverse reaction and their lung tissue became inflamed. "It was not life-threatening, but nonetheless it was a concerning reaction," Dr Higgins said. However, he said the search for weevil and fungus-resistant peas would continue, using the gene transfer system that was developed at the CSIRO as part of a $3million project. In an earlier case of GM research, work on a protein-enhanced soy product was abandoned when it was discovered that the brazil nut gene transferred to the soy produced a protein that could cause allergic reactions in some people. Grains Research and Development Corporation managing director Peter Reading said it was good to be able to identify problems "early in the piece". A spokeswoman for Bayer Crop Sciences, also involved in researching GM products, said the CSIRO's decision had no impact on the firm's GM work. Melbourne-based Monsanto - which has developed several GM food products, including corn - was unavailable for comment yesterday. <<<<>>>> Transgenic Expression of Bean -Amylase Inhibitor in Peas Results in Altered Structure and Immunogenicity Vanessa E. Prescott, Peter M. Campbell, Andrew Moore, Joerg Mattes, Marc E. Rothenberg, Paul S. Foster, T. J. V. Higgins, and Simon P. Hogan* Division of Molecular Bioscience, The John Curtin School of Medical Research, Australian National University, Canberra, ACT, Australia, Division of Allergy and Immunology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, Ohio 45229, and Divisions of Entomology and Plant Industry, Commonwealth Scientific and Industrial Research Organization, Canberra, ACT, Australia Received for review March 16, 2005. Revised manuscript received August 26, 2005. Accepted September 6, 2005. This work was supported in part by National Health Medical Research Council (Australia) Program Grant 224207. Abstract: The development of modern gene technologies allows for the expression of recombinant proteins in non-native hosts. Diversity in translational and post-translational modification pathways between species could potentially lead to discrete changes in the molecular architecture of the expressed protein and subsequent cellular function and antigenicity. Here, we show that transgenic expression of a plant protein (-amylase inhibitor-1 from the common bean (Phaseolus vulgaris L. cv. Tendergreen)) in a non-native host (transgenic pea (Pisum sativum L.)) led to the synthesis of a structurally modified form of this inhibitor. Employing models of inflammation, we demonstrated in mice that consumption of the modified AI and not the native form predisposed to antigen-specific CD4+ Th2-type inflammation. Furthermore, consumption of the modified AI concurrently with other heterogeneous proteins promoted immunological cross priming, which then elicited specific immunoreactivity of these proteins. Thus, transgenic expression of non-native proteins in plants may lead to the synthesis of structural variants possessing altered immunogenicity. http://pubs.acs.org/cgi-bin/abstract.cgi/jafcau/2005/53/i23/abs/jf050594v.html