Odor map helps synthesize smells

Weizmann Institute research may enable odors to be digitized and transferred via computer.

nose 88 (photo credit: )
nose 88
(photo credit: )
Is the smell of almonds closer to that of roses or bananas? Weizmann Institute researchers have answered that question (roses) by showing that smells can be mapped and the relative "distance" between various odors determined. Their findings, which appeared recently in Nature Methods, may help scientists unravel the laws underlying our sense of smell, as well as enabling odors to be digitized and transferred via computer. We know the musical note "do" is farther from "la" than from "re" - not only because our ears tell us the distance is greater, but because their frequencies are farther apart. No such physical relationship had been discovered for smells - in part because odor molecules are much more difficult to pin down than sound frequencies. To create their map, the scientists began with 250 odorants and generated for each a list of 1,600 chemical characteristics. From this dataset, the researchers, led by Rafi Haddad, a graduate student with Prof.Noam Sobel in the neurobiology department, and Prof.David Harel of the computer science and applied mathematics department, together with colleague Rehan Khan, created a multi-dimensional map that revealed the distance between one odor molecule and another. Eventually, they reduced the list of traits needed to situate an odor on the map to around 40. They then checked to see whether the brain recognizes this map in the same way it recognizes musical scales. They reexamined previously published studies that measured the neural responses to smells in a variety of lab animals, and found that across all species, the closer any two smells were on the map, the more similar the neural patterns. The scientists also tested 70 new odors by predicting the neural patterns they would arouse and running comparisons with the unpublished results of olfaction experiments done at the University of Tokyo. They found that their predictions closely matched the experimental results. These findings lend support to the scientific theory that - contrary to the commonly held view that smell is a subjective experience - there are universal laws governing the organization of smells. PIZZA HERB KILLS CEREAL BUGS Oregano is tasty on pizza, but oregano oil has been found by scientists in Algeria to work as well as synthetic insecticides to combat a common beetle found in stored cereals. The researchers, whose paper appeared recently in the Journal of the Science of Food and Agriculture, told UPI that not only does oregano oil work well in fighting infestations of Rhizoppertha dominica - but it has none of the environmental side effects of synthetic insecticides. Oregano, a member of the Lamiaceae family of plants, has been known to be a natural insecticide because it apparently inhibits egg laying and larval development. But the researchers said their study marks the first time oregano oil has been looked at as a viable alternative to synthetic insecticides. Chahrazed Boutekedjiret and colleagues from Algeria's National Polytechnic School identified 18 components in oregano oil that combat pests and found the greater the concentration of the oil used, the more effective it was. THE WAY OF THE DODO Say goodbye to some of your favorite animal species, as many are rapidly becoming extinct. The World Wildlife Fund (WWF) says more than a quarter of the Earth's wildlife has been lost during the past 35 years. The organization's Living Planet Index - produced for the WWF by the Zoological Society of London - shows populations of marine species such as swordfish and scalloped hammerhead were particularly hard hit, falling by 28 percent between 1995 and 2005. Seabird populations have suffered a 30% decline since the mid-1990s. The index, reported UPI, said land-based species' populations fell by 25% between 1970 and 2005, and populations of freshwater species by 29% between 1970 and 2003. Habitat destruction and wildlife trade were among the major causes, but climate change is expected to become an increasingly important factor. "No one can escape the impact of biodiversity loss," said WWF director-general James Leape, "because reduced global diversity translates quite clearly into fewer new medicines, greater vulnerability to natural disasters and greater effects from global warming."