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Fatty foods aid memory recall
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GREAT news for beauty queens. Self-tanning lotion’s nasty smell can be chemically neutralised. Using established techniques called headspace and thermal desorption analysis, Tim Whiteley of CPL Aromas in Bishop’s Stortford, UK, and colleagues captured odour molecules from the air as self tan was applied to various skin types. They identified 250 to 300 different molecules. Some particularly smelly ones, including sulphur dioxide, were specific to the reaction between collagen and the chemical dihydroxyacetone (DHA), an active ingredient in fake tan. Male skin generated the most smell – possibly because the upper layer of skin in men is thicker, so there is more collagen for the DHA to react with. Next, the team tested chemicals they suspected would react with the smelly molecules to produce larger molecules that could no longer be smelled, or a different shape that would be perceived differently by the nose. They managed to reduce sulphur dioxide 12-fold, and several other smelly molecules by a significant amount. Professional sniffers reported a 70 per cent reduction in their perception of the unpleasant smell on users’ skin, the team claims. The Aromaguard technology was launched last week in St Tropez self-tan products.
Remember the facts by cramming with fat INDULGING in a fatty meal after studying for an exam could boost your results. A study in rats shows that eating a certain type of fat produces a hormone that helps the brain cement short-term memories into long-term ones. Daniele Piomelli and colleagues at the University of California at Irvine trained rats to complete two tasks: avoid an area that gave them a shock, and find a platform in a pool of water. Immediately after the training periods, they injected some of the rats with oleoylethanolamide (OEA) – a
chemical produced in the small intestine of vertebrates which creates a sense of fullness after eating fat. When the rats were retested one or two days later, the ones that received OEA performed better, suggesting they had stronger memories of their training (Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.0903038106). More experiments with the rats showed that OEA activates the same areas of the brain that mediate the formation of emotionally charged memories in humans, which are
more vivid than typical memories. The findings make sense from an evolutionary perspective, says Piomelli. When foraging animals find a fatty meal, they do well to remember exactly where and how they found it. Since humans also produce OEA, Piomelli says there is a good chance that it boosts our memory too. OEA is only produced after eating a healthy unsaturated fat called oleic acid, so a cheeseburger after a night of cramming may not work – try food with olive oil or soybean oil, says Piomelli. BYEONG CHUN LEE
Fake tan without the telltale smell
Protein programme for safer stem cells SPECIALISED cells have been rewound to an embryonic state using proteins rather than genes, a technique that reduces the risk of triggering cancer. The first “induced pluripotent” stem (iPS) cells were created by inserting four genes into the chromosomes of mouse or human skin cells. However, the same genes can also trigger tumours. Now researchers led by Sheng Ding of the Scripps Research Institute in La Jolla, California, have dodged this potential problem by inserting the proteins encoded by the four genes directly into the target cells. They attached each protein to polyarginine, which consists of a string of 11 copies of the amino acid arginine. This molecule readily crosses cell membranes, dragging with it any attached protein. Ding’s team bathed mouse cells taken from connective tissue in a cocktail of the four polyarginine-tagged proteins for 12 hours, removed the reprogramming proteins for 36 hours, then repeated this cycle four times. About two weeks later, they were able to extract colonies of iPS cells (Cell Stem Cell, DOI: 10.1016/j.stem.2009.04.005).
First transgenic dog has healthy glow MEET Ruppy, the ruby-coloured puppy that is the world’s first transgenic dog. She and four other cloned beagles have a gene that makes them glow red under UV light. They may pave the way for new animal models of human disease. A team led by Byeong-Chun Lee of Seoul National University in South Korea – who helped create the first cloned dog, named Snuppy – infected dog fibroblast cells with a virus that inserted the fluorescent gene into their nuclei. Then they transferred the nuclei into egg cells that had been emptied of their original nuclei.
Next they implanted the cloned embryos into surrogate mothers, resulting in seven pregnancies – five of these offspring are still alive (Genesis, DOI: 10.1002/dvg.20504). In future, the same technique could be used to produce cloned dogs with genes for human disease, or with certain relevant genes knocked out. Team member CheMyong Ko of the University of Kentucky in Lexington says such transgenic dogs may be useful for studying human fertility, as dogs’ long lifespan and reproductive cycle makes them more relevant to people than mice.
2 May 2009 | NewScientist | 15
TROY AOSSEY/STONE/GETTY
GREAT news for beauty queens. Self-tanning lotion’s nasty smell can be chemically neutralised. Using established techniques called headspace and thermal desorption analysis, Tim Whiteley of CPL Aromas in Bishop’s Stortford, UK, and colleagues captured odour molecules from the air as self tan was applied to various skin types. They identified 250 to 300 different molecules. Some particularly smelly ones, including sulphur dioxide, were specific to the reaction between collagen and the chemical dihydroxyacetone (DHA), an active ingredient in fake tan. Male skin generated the most smell – possibly because the upper layer of skin in men is thicker, so there is more collagen for the DHA to react with. Next, the team tested chemicals they suspected would react with the smelly molecules to produce larger molecules that could no longer be smelled, or a different shape that would be perceived differently by the nose. They managed to reduce sulphur dioxide 12-fold, and several other smelly molecules by a significant amount. Professional sniffers reported a 70 per cent reduction in their perception of the unpleasant smell on users’ skin, the team claims. The Aromaguard technology was launched last week in St Tropez self-tan products.
Remember the facts by cramming with fat INDULGING in a fatty meal after studying for an exam could boost your results. A study in rats shows that eating a certain type of fat produces a hormone that helps the brain cement short-term memories into long-term ones. Daniele Piomelli and colleagues at the University of California at Irvine trained rats to complete two tasks: avoid an area that gave them a shock, and find a platform in a pool of water. Immediately after the training periods, they injected some of the rats with oleoylethanolamide (OEA) – a
chemical produced in the small intestine of vertebrates which creates a sense of fullness after eating fat. When the rats were retested one or two days later, the ones that received OEA performed better, suggesting they had stronger memories of their training (Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.0903038106). More experiments with the rats showed that OEA activates the same areas of the brain that mediate the formation of emotionally charged memories in humans, which are
more vivid than typical memories. The findings make sense from an evolutionary perspective, says Piomelli. When foraging animals find a fatty meal, they do well to remember exactly where and how they found it. Since humans also produce OEA, Piomelli says there is a good chance that it boosts our memory too. OEA is only produced after eating a healthy unsaturated fat called oleic acid, so a cheeseburger after a night of cramming may not work – try food with olive oil or soybean oil, says Piomelli. BYEONG CHUN LEE
Fake tan without the telltale smell
Protein programme for safer stem cells SPECIALISED cells have been rewound to an embryonic state using proteins rather than genes, a technique that reduces the risk of triggering cancer. The first “induced pluripotent” stem (iPS) cells were created by inserting four genes into the chromosomes of mouse or human skin cells. However, the same genes can also trigger tumours. Now researchers led by Sheng Ding of the Scripps Research Institute in La Jolla, California, have dodged this potential problem by inserting the proteins encoded by the four genes directly into the target cells. They attached each protein to polyarginine, which consists of a string of 11 copies of the amino acid arginine. This molecule readily crosses cell membranes, dragging with it any attached protein. Ding’s team bathed mouse cells taken from connective tissue in a cocktail of the four polyarginine-tagged proteins for 12 hours, removed the reprogramming proteins for 36 hours, then repeated this cycle four times. About two weeks later, they were able to extract colonies of iPS cells (Cell Stem Cell, DOI: 10.1016/j.stem.2009.04.005).
First transgenic dog has healthy glow MEET Ruppy, the ruby-coloured puppy that is the world’s first transgenic dog. She and four other cloned beagles have a gene that makes them glow red under UV light. They may pave the way for new animal models of human disease. A team led by Byeong-Chun Lee of Seoul National University in South Korea – who helped create the first cloned dog, named Snuppy – infected dog fibroblast cells with a virus that inserted the fluorescent gene into their nuclei. Then they transferred the nuclei into egg cells that had been emptied of their original nuclei.
Next they implanted the cloned embryos into surrogate mothers, resulting in seven pregnancies – five of these offspring are still alive (Genesis, DOI: 10.1002/dvg.20504). In future, the same technique could be used to produce cloned dogs with genes for human disease, or with certain relevant genes knocked out. Team member CheMyong Ko of the University of Kentucky in Lexington says such transgenic dogs may be useful for studying human fertility, as dogs’ long lifespan and reproductive cycle makes them more relevant to people than mice.
2 May 2009 | NewScientist | 15