|Danny KesslerDELICATE BALANCE - Wild tobacco plants use a finely tuned combination of chemical compounds that attract and repel pollinators, like the hummingbird and bee (above), so that pollinating insects will visit, but not stay too long nor drink too much nectar, researchers say. Danny Kessler and his colleagues at the Max Planck Institute for Chemical Ecology in Germany genetically manipulated the levels of benzyl acetone, the plant's main attractant, and nicotine, their main repellant. Their findings show benzyl acetone is related to increased pollinator visits, and nicotine enforces modest drinking behavior among pollinating insects. This research appears in the Aug. 29 issue of Science. (Danny Kessler)|
Estrogen helps form memories in mice
Menopausal women often complain of memory problems. Since estrogen levels plummet following menopause, one theory holds that estrogen normally helps with memory formation. Mice injected with estrogen, for example, perform better at memory-related tasks, like navigating through a maze or recognizing objects. But so far, its been unclear how estrogen acts chemically in the brain. Now, research from the Department of Psychology at Yale University provides the first hard evidence suggesting that estrogen helps to chemically fine-tune the molecules in the brain responsible for generating a memory. Researchers found that mice that received injections of estrogen in the hippocampus, one of the memory centers of the brain, were better at recall tasks. The injected mice also had changes in a certain molecule in the brain, called ERK, that is associated with memory formation. "Clinically, we might be able to develop drugs that target ERK to help menopausal women with memory loss, without having to risk the side effects of estrogen replacement," said principal investigator Karyn Frick. Estrogen-replacement therapy has come into question because of its association with increased cardiovascular and breast cancer risk. BOTTOM LINE: Estrogen has been shown to have a direct chemical effect on the signaling molecules implicated in memory formation in the brain. CAUTIONS: The experiments were done in mice, not in humans. WHAT'S NEXT: The mice used in these experiments were young - so researchers plan on repeating the studies in aging female mice to more accurately represent the menopausal population. WHERE TO FIND IT: The Journal of Neuroscience, Aug. 27 SUSHRUT JANGI
BOTTOM LINE: "The brain is far more plastic than we previously believed," said Pascual-Leone. "Understanding these rapid changes in the brain can help devise strategies for treating blindness."
CAUTIONS: The brain "plasticity" observed in blindfolded participants may not be the only change taking place in blind people to account for their enhanced tactile abilities.
WHAT'S NEXT: The researchers want to find out how blindness affects the visual cortex's ability to process sound and memory, and the mechanism of suppression and unmasking of these abilities.
WHERE TO FIND IT: Public Library of Science ONE online, Aug. 27
SENA DESAI GOPAL