Title: Genetically modified tomatoes may be good for you
Key words: genetically engineered tomatoes, lycopene, carotene, antioxidants, DNA, heart disease, cancer, mutation
Date: April 2001
Brighter future for vegetables
Salads could become more colourful - and healthier - thanks to unusually red tomatoes that could help to protect people against cancer and heart disease.
Peter Bramley and his colleagues at Royal Holloway College, London, have genetically engineered tomatoes so that they contain unusually large amounts of lycopene and beta-carotene. These compounds are among a group of chemicals called antioxidants that are thought to mop up highly reactive compounds called free radicals inside cells. Left at large, free radicals can damage DNA, possibly leading to cancer-causing mutations. Free radicals are also believed to play a role in the development of heart disease, triggering reactions that lead arteries to fur up with fatty deposits.
Bramley's tomatoes are so red because they contain twice as much lycopene, the pigment that makes tomatoes red, as normal. "Normal tomatoes usually have paler portions inside, but these ones have even, red pigmentation throughout," he says.
They also contain abnormally high levels of beta-carotene, the compound that makes carrots bright orange. Both are carotenoids, a group of compounds found widely in fruit and vegetables. "If we can establish that higher levels of carotenoids in the diet are beneficial, we are developing technology to modify common fruit and vegetables so that they produce more, he says.
Bramley produced the extra lycopene and beta-carotene by inserting a gene into tomatoes that makes phytoene synthase, the compound in plants that triggers the synthesis of many carotenoids.
Bramley and his colleagues have just begun to evaluate some 30 other types of carotenoid. They are also studying which genes, or groups of genes, they may need to insert to raise the production of beneficial carotenoids. If the work with tomatoes is successful, Bramley hopes to engineer other fruits and vegetables, including peppers and carrots.
From New Scientist magazine, vol 147 issue 1995, 16/09/1995, page 11
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