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Colin Macilwain
Syngenta admits 150 square kilometres accidentally sown with wrong seeds.
A strain of genetically modified corn that does not have regulatory approval has been distributed by accident over the past four years, Nature has learned.
Syngenta, one of the world's largest agricultural biotechnology companies, revealed the mistake to US regulators at the end of last year. Although the crop is believed to be safe, the fact that it was sold for years by accident raises serious questions about how carefully biotechnology firms are controlling their activities, critics say.
The corn (maize) was modified with a gene from the soil bacterium Bacillus thuringiensis (Bt), which is inserted into the crop to act as a pesticide. Syngenta has approval to sell a variety of the transgenic crop called Bt11, which has been used successfully for many years in the United States and elsewhere. The strain has been approved for consumption in the European Union, for example, and may be one of the first food crops approved for cultivation there.
But between 2001 and 2004, Syngenta inadvertently produced and distributed several hundred tonnes of Bt10 corn - a different genetic modification that has not been approved.
Since the release was discovered in late 2004, US government scientists have assessed the Bt10 corn - which differs from Bt11 by only a handful of nucleotides on a section of the gene that does not code for the protein toxin - and have concluded that it is safe to eat and poses no environmental threat.
"What makes this somewhat unique is that Bt10 and Bt11 are physically identical and the proteins are identical," says Jeff Stein, head of regulatory affairs at Syngenta in Research Triangle Park, North Carolina.
Sarah Hull, a spokeswoman for the company in Washington DC, adds that Syngenta promptly reported the mistake to regulators after the discovery. She says this shows that the system is working as it should do. Company officials also note that the release was relatively small. About 150 square kilometres of the crop was planted over the four years, they say, which is 0.01% of all corn planted in the United States during that period. As Bt corn seed has to be bought every year, rather than being gathered from the previous year's crop, the problem should not escalate.
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--AMITABH AVASTHI
A new technique that creates tiny magnets in cells may enable MRI scans to visualize gene expression in living organisms. The technique may also one day help scientists visualize therapeutic gene delivery in humans.
At present, gene expression is imaged with the help of "reporters" such as green fluorescent protein, which causes cells to fluoresce when specific genes are turned on. But the technique is limited to the areas of the body that light can penetrate, like the skin. As an alternative, scientists have considered using magnetic resonance imaging (MRI), which detects differences in magnetic fields between tissues. But because the magnetic fluid injected into the body in traditional MRI does not penetrate well into cells and tissue, this method also prevents scientists from visualizing cells deep within the body.
To surmount the problem, Eric Ahrens and his colleagues at Carnegie Mellon University in Pittsburgh, Pennsylvania, wondered if they could force cells to make their own magnetic agent. The search led them to ferritin, an iron-containing protein found in all organisms. When the team injected a virus containing the ferritin gene into mouse brains, an MRI scan revealed a dark patch, indicating that the new reporter gene was turned on. Ahrens, whose group reports its findings in the April issue of Nature Medicine, says the method could someday be used to track the delivery of therapeutic transgenes into the body.
In the meantime, this proof-of-concept is a milestone. "The development of reporter gene for MRI has been an elusive goal for a long time," says Jeff Bulte, a molecular imaging scientist at Johns Hopkins University in Baltimore, Maryland. "This is the first study to basically show this works."
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Scientists have transformed stem cells from adult human bone marrow into nerve cells by transplanting them into damaged chicken embryos.
The University of Oslo team hopes the breakthrough could lead to a new source of cells to treat brain diseases such as Parkinson's.
It appeared that the embryos' internal repair mechanism acted on the cells to profoundly change their make-up.
Details are published in Proceedings of the National Academy of Sciences.
Stem cells are master cells with the ability to form different kinds of tissue. But those from adult bone marrow normally produce blood and immune system cells.
However, experiments have suggested it might be possible to coax them into becoming nerves.
Attempts to achieve this have, in the past, been relatively unsuccessful.
In a small number of cases, scientists have managed to identify the molecular hallmarks of neurons - but they have not been able to create properly formed interconnected cells.
However, bone marrow stem cells implanted into chicken eggs developed fully functional physical features. They were also converted at a high rate of about 10%.
Writing in PNAS, the researchers said: "This may open new possibilities for a high-yield production of neurons from a patient's own bone marrow."
The Norwegian team used a micro-surgery technique to cut out a small section of the developing spinal cord within the chicken egg.
Stem cells were transplanted into chicken eggs Human haematopoietic stem cells (hHSCs) from bone marrow were then implanted into the damaged area.
The eggs were incubated before the embryos were removed, and spinal cord slices containing human cells dissected out and analysed.
Damage to the developing brain and spinal cord of the chicken embryo is automatically repaired through a process called regulative regeneration.
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By Karen Kaplan, Times Staff Writer
Upending prevailing genetic theory, a team of scientists at Purdue University has discovered a mechanism in plants that allows them to correct defective genes from their parents by tapping into an ancestral data bank of healthy genetic material.
In essence, the plants back up the evolutionary path and use past genes to restore traits that would otherwise be lost, according to a study published Tuesday in the online version of the journal Nature.
The finding proposes "an extraordinary view of inheritance," the scientists said in their paper.
The mechanism appears to be a way for self-fertilizing plants, which are more likely to suffer from the negative consequences of inbreeding, to maintain a healthy level of genetic diversity and increase their chances of survival.
It could also be a way for plants to adapt to changing environmental conditions by having a store of diverse traits at their disposal, the scientists said.
The proposal offers a radical addition to the widely embraced laws of Mendelian genetics, which date back to the mid-1800s. They hold that plants and animals inherit only two copies of a gene — one from each parent. If both copies were defective, a plant would have no ability to correct the error.
"This means that inheritance can happen more flexibly than we thought in the past," said Robert Pruitt, a molecular geneticist who co-authored the paper. "While Mendel's laws that we learned in high school are still fundamentally correct, they're not absolute."
If the newly discovered mechanism is also found to be at work in people, "it's possible that it will be an avenue for gene therapy to treat or cure diseases in both plants and animals," Pruitt said.
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The herbicide management of genetically-modified herbicide-tolerant (GMHT) winter-sown oilseed rape results in differences in the types of weeds present, compared to growing conventional varieties, according to a paper published today (Monday 21 March 2005) in the Proceedings of the Royal Society B: Biological Sciences*.
Sixty-five fields were sown with winter oilseed rape. Each field was split, one half being sown with a conventional variety managed according to the farmer’s normal commercial practice for weed control, the other half being sown with a GMHT variety, with weeds controlled by a broad-spectrum herbicide called glufosinate-ammonium. Comparisons in biodiversity were made by looking at the levels of weeds and invertebrates, such as beetles, butterflies and bees.
At harvest time, in the GMHT crop, both the amount of broad-leaved flowering weeds and the number of their seeds, which provide food for wildlife, were one-third of those in the conventional. But in the GMHT crops there were three times as many grass weeds and five times as many of their seeds as in the conventional. These effects were observed in the year of cropping and persisted in the following two years that data were collected. For the total amounts of weeds found, there was little difference between GMHT and conventional cropping.
For the majority of invertebrate species there was no significant difference between the GMHT and conventional herbicide regimes. However, by the July sampling, there were half the number of bees and two-thirds the number of butterflies found foraging in the GMHT crop areas, compared to the conventional. Also, consistent with previous Farm Scale Evaluation (FSE) results reported for spring-sown crops, the yearly totals for springtails, a type of detritivore which feeds on dead and decaying weeds, were higher in the GMHT crop areas.
Dr David Bohan, one of the authors of the paper, said: “These results present a number of interesting similarities with, but important differences to, the results for the spring-sown crops in the FSEs published in 2003. In terms of broad-leaved flowering weeds, the effects were broadly similar in winter-sown oilseed rape to those seen previously in spring-sown oilseed rape, with smaller numbers found in the GMHT crop area. But with grass weeds there was a significant difference, with many more present in the winter-sown GMHT crop. This resulted from relatively poor control of the grass weeds by late-applied glufosinate-ammonium to the GMHT crops compared with herbicides applied much earlier in the conventional.”
Dr Bohan continued: “Surprisingly, given the link between numbers of weeds and numbers of invertebrates seen in the spring-sown crops, most species were unaffected by the changes in amounts of broad-leaved and grass weeds in the winter-sown crop.”
Dr Bohan summarised: “The study demonstrates the importance of the effects of herbicide management on wildlife in fields and adjacent areas.”
The paper can be viewed online, free-of-charge, at:
http://www.pubs.royalsoc.ac.uk/proc_bio_content/pdf/rspb20043049.pdf
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Gretchen Vogel
BERLIN--Researchers at two government-funded labs in Germany have had to withdraw from projects involving the safety of genetically modified (GM) plants after their bosses, officials in the agriculture ministry, said the work was inappropriate. The ban came despite the fact that the projects won funding from another government department--the ministry of research and education--in a nationwide competition for projects studying GM plant safety.
The showdown is the latest example of political hostility toward GM research in Germany, says Jörg Hacker of the University of Würzburg, a vice president of the federal research agency DFG. Even so, he says, the cancellation of specific projects is unprecedented: "To my knowledge, it's the first time such a thing has happened." The projects involved "one of the core concerns of the ministry," he adds, to improve the safety of GM plants.
Agriculture and consumer protection minister Renate Künast, a Green Party member of the left-leaning governing coalition and the researchers' ultimate boss, is openly skeptical of gene technology. Last year, her ministry proposed a law that holds anyone who plants GM crops financially liable if neighboring fields are contaminated with genetically altered pollen. Scientists have complained that the law, which received final approval from the Bundestag in December, essentially prevents all field research with GM plants (Science, 25 June 2004, p. 1887).
The researchers leading the projects, Joachim Schiemann of the Institute for Plant Virology, Microbiology, and Biosafety in Braunschweig and Reinhardt Töpfer of the Federal Center for Cultivated Plant Breeding Research in Siebeldingen, hoped to optimize a method for removing antibiotic-resistance genes from GM plants. During the genetic alteration process, antibiotic-resistance genes are commonly introduced as markers. Their presence in GM plants is often cited by opponents of the technology as a potential danger to consumers and the environment. A spokesperson for the agricultural ministry says the projects could lead to products that would later need to be evaluated by the institutes in question, and the ministry acted to prevent potential conflicts of interest.
The researchers were not available for comment, but a member of Schiemann's consortium, Inge Broer of the University of Rostock, says the research will go on. Her group will take over the project, she says, "but we have enough other work to do. It would be better if the [agriculture ministry] researchers did it themselves." If the government hopes to properly assess the safety of GM crops, she says, they will need qualified experts in the field.
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Eli Kintisch
The once-solid political coalition in the United States that opposes any form of human cloning is showing signs of splintering over strategy. Supporters of cloning research are paying close attention to the rift, first reported in the Washington Post last week, wondering whether it may work to their advantage or lead to new laws restricting research that stretches ethical boundaries.
One camp, led by Senator Sam Brownback (R-KS) and pro-life groups, seeks to renew the fight to pass a comprehensive ban on all cloning of human embryos. Brownback, who plans to reintroduce legislation this week, and others have tried to capitalize on the near-universal aversion to the notion of cloning a human to also ban the use of somatic cell nuclear transfer (SCNT) to create early-stage embryos for research. Citing SCNT's potential to elucidate and perhaps treat diseases such as Parkinson's, research and patient groups have thwarted such legislative efforts to date.
In recent months a new camp has emerged, led by Leon Kass, chair of the President's Council on Bioethics, and Eric Cohen, editor of the conservative bioethics journal The New Atlantis. Frustrated that Congress has repeatedly failed to pass anticloning measures, they call for a broader ban on novel reproductive approaches, including cloning humans. Arguing that semantics have trumped ethics in the cloning debate thus far, they also want to "delink" restrictions on novel reproduction from those on research cloning by dealing with them in separate bills--an approach that those in favor of research cloning have advocated in the past.
One of several position papers Kass and others have discussed during informal meetings, recently posted on a Web site, calls first for legislation that would protect "the Dignity of Human Procreation." It seeks to ban reproductive cloning and other procedures including transferring a human embryo into an animal or using sperm or eggs from fetuses to create a child. A "ban on all human cloning does nothing to prevent other ways of making children that would be unwise or unethical," explains Cohen. (An aide to Brownback says the senator will introduce additional legislation soon that would outlaw ethically questionable reproductive methods.)
The document recommends lobbying for a second law that would ban "the creation of any human embryo [through cloning or IVF] solely for research and destruction." It's this tactic, in particular, that has divided the two anticloning camps. Brownback and others say that delinking reproductive and research cloning would give supporters of research cloning a political advantage. "Tactically, [the first] might pass, and you would weaken the case for the other," says David Prentice, senior fellow at the conservative Family Research Council.
Others say the new proposals are unlikely to change the political deadlock. "Congress could pass a ban on reproductive cloning with or without these other prohibitions, and we're going to stay divided on the research cloning," says Kathy Hudson, director of the Johns Hopkins University Genetics and Public Policy Center in Washington, D.C.
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Several months after the UK anti-GM movement reached its peak, environmental group Greenpeace continues to lobby against supermarkets that advertise milk as GM-free – despite it originating from cattle fed on imported GM maize and soya, Tom Armitage reports.
Last week the company staged another protest in Cardiff, Wales, claiming that, “a number of UK supermarkets and dairy companies are still allowing their suppliers to feed their cattle GM ingredients”.
Marks and Spencer remains the only major UK retailer to stock its entire milk range produced from animals fed on organic feed, although the UK’s third largest supermarket Sainsbury’s has rolled out similar milk trials across 190 of its stores, displayed alongside its existing range of organic, gold top and standard milks.
“All our milk is GM-free, although we do stock some milk which has been made from cattle reared on GM ingredients,” Sainsbury’s commented.
“We give our customers a choice. Milk which is sourced from non-organic ingredients is clearly labelled to avoid any confusion.”
The UK’s food industry regulator, the Food Standards Agency (FSA), together with several science and industry bodies, last year produced extensive research showing that neither GM DNA or protein was found in milk samples orginating from cattle reared on GM feed.
The British Retail Consortium, the trade association for UK retailers, lambasted Greenpeace for “creating unnecessary food fear through misleading claims that are without scientific foundation”.
“Retailers in Wales and the rest of the UK provide total choice for their customers when it comes to milk. Whatever a customer needs, they can find it on the shelves and make an informed decision on what they buy,” it added.
Greenpeace estimates that British dairy producers could change their feed ingredient arrangements from GM to non-GM for less than 1p per litre, although it argues that supermarkets - not farmers - would be best placed to accommodate this cost due to the sizable margins they reap.
But it appears that this suggestion remains impractical to implement and somewhat contentious
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