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April 12, 2004 |
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Plants Dispatched to Decontaminate Soil |
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Scientists have recruited plants in their fight against pollution. Specifically, they have teamed the yellow lupine with modified bacteria that can break down organic chemicals. According to a report in the May issue of Nature Biotechnology, the combination is very effective at removing the toxic compound toluene from soil. What is more, the bacteria break down the chemical within the plant, resulting in a 70 percent reduction in the amount of toluene released through its leaves.
To create the novel chemical-devouring duo, Daniel van der Lelie of Brookhaven National Laboratory and his colleagues inserted the machinery to break down toluene from one bacterium, Burkholderia cepacia G4, into a second type of bacterium, B. cepacia L.S.2.4, which occurs naturally inside yellow lupine. Toluene is a water-soluble organic compound that is widely used as a solvent and is present in products such as paint thinner, nail polish remover and adhesives. Plants containing the modified B. cepacia that were grown in toluene-seeped soil showed no signs of toxicity, because the bugs protected them. Plants lacking the modified bacteria can also draw toluene out of the ground, but the chemical is later released from the leaves through evaporation. Plants carrying B. cepacia, in contrast, returned far less toluene to the atmosphere. Depending on the type of bacteria utilized, the approach can clear a variety of pollutants. "Other applications we envisage include the use of engineered endophytic bacteria to degrade pesticide and herbicide residues in crop plants, addressing important food safety related issues," the scientists write. The team�s next step is to expand the work to other types of trees--including poplars and willows--to clean up contaminated groundwater. --Sarah Graham |
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� 1996-2004 Scientific American, Inc. All rights reserved. Reproduction in whole or in part without permission is prohibited. | ||
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April 20, 2004 |
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Cloned Cows Manufacture Cancer Treatment |
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The products most closely associated with cows are milk and beef. But European scientists report today in the Proceedings of the National Academy of Sciences that the animals can be bred to generate antitumor drugs. The findings could lead to a novel way of manufacturing antibodies for tumor therapy on a large scale.
Drugs employing antibodies that recognize proteins found only on cancerous cells tend to work more effectively when paired with a second type of antibody that targets immune cells. But these so-called bispecific antibodies are difficult to produce, so Gottfried Brem of the University of Veterinary Medicine in Vienna and his colleagues tried a new approach. The researchers first linked two genes, one that targets human melanoma cells and one that activates T cells, and inserted the resulting genetic sequence into cow embryos. The nine animals that developed (see image) had high levels of the desired designer antibody, called r28M, in their bloodstreams. The scientists were able to extract and purify significant quantities of r28M, and test it against human melanoma cells. According to the report, the protein is stable and successfully targeted and killed cancer cells in laboratory tests. The authors suggest that this gene farming approach could be tailored to produce a variety of proteins. Their results, they conclude, emphasize "the fact that blood cells can be directed to produce high concentrations of fully active therapeutic molecules that are otherwise difficult to express." --Sarah Graham |
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� 1996-2004 Scientific American, Inc. All rights reserved.
Reproduction in whole or in part without permission is prohibited. ====
Like it or not, GM organisms and products are here -- with hundreds of thousands to come. It is the Brave New World already ... | ||
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