Odortypes: Nature or Nurture?

Numerous studies have shown that, from mice to men, the bodies of mammals have genetically-determined signature odors, known as odortypes. But we also know that the type of food consumed by an individual can influence body odor. The question is, to what degree can diet alter this olfactory fingerprint? Could a fleeing fugitive throw the hounds off his scent by, say, pausing for a large lunch of garlic and onions?
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Smell Less, Live Longer?

The effects of a low-calorie diet on the longevity of most animals is widely known in scientific circles: Caloric restriction extends animal lifespans by activating cellular protection mechanisms. But, according to a new study into the lifespans of roundworms, just restricting the smell of those calorie-filled foodstuffs may turn the trick!

Three years ago, researchers at Washington University School of Medicine in St. Louis discovered that a class of anticonvulsant medications increased the lifespan of a roundworm, but prior to concluding their new study, they had no idea why. “We’ve learned that the drugs inhibit neurons in the worm’s Read more

A Nose Fit for a Bionic Man

The mainstream use of Artificial Noses–which could conceivably replace drug, bomb, and even diabetes and cancer-sniffing dogs–may finally be on the horizon, thanks to biological engineers at MIT, who have discovered a way to mass-produce smell receptors in the laboratory. Moreover, the discovery may help researchers to understand how the sense of smell is able to recognize a seemingly infinite range of odors.
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The Science of Olfactory Diagnosis

The smell of rotten apples on a patient’s breath doesn’t positively indicate diabetes, and fishy breath doesn’t positively indicate liver disease–any more than the smell of Smirnoff positively indicates alcoholism–but it can give a physician Read more

Eradicating Hepatitis B with the Mucosal Vaccine

Even with the existence of effective vaccinations, hepatitis B continues to kill more than a million people each year. Traditional injected vaccines present challenges which are particularly cumbersome in developing nations, including the need for a supply of sterile needles, constant refrigeration, and three separate treatments. Such obstacles may soon be a thing of the past, according to a new study on a nasal hepatitis B vaccine which require no needles, refrigeration, or multiple doses. But is it effective? In a word, Yes. The mucosal vaccine triggered an astounding protective response in animals roughly 450 times greater than that of currently approved vaccines, producing three distinct types of immunity–mucosal, cellular and systemic.

Mucosal vaccines are delivered directly to the lining of the nose where immune cells recognize the foreign antigen, causing rapid stimulation of the immune system, and do not involve the inflammatory chemicals used in injected vaccines. “We have developed a new vaccine that is extremely safe, easy to administer, and which rapidly builds protection against hepatitis B infection,” said Dr. James R. Baker Jr., founder of NanoBio Corp, which has exclusive rights to commercialize the new vaccine technology. Read more

Simple Testing for Little Noses

With increasing evidence that an impaired sense of smell can be an early indicator of everything from sinus and ear infection to schizophrenia and Alzheimer’s disease, development of accurate methods of measuring olfactory function has become a diagnostic priority. While effective clinical tests are in use for adults, such as the OLFACT, most are considered unsuitable for children because they tend to test for a complex range of smells unknown to a child.

Recognizing the need for testing on a more “Fun With Dick and Jane” level, researchers from the University of New South Wales have developed a simplified odor identification test involving 16 common odorants (such as fish, cut grass, and chocolate) and simple visual images geared toward children aged five to seven. Study participants sniffed the odors from individual plastic bottles, then viewed three photographs and picked the one that best represented the smell. 88.1% of five-year-olds, 88.9% of six-year-olds, and 91.1% of seven-year-olds correctly identified the smells. For a five-year-old, say the researchers, normal olfaction would be defined by correct identification of 11 out of the 16 odors, and anosmia would be signaled by correct identification of 4 or less.

While early results are extremely promising, the researchers point out that “as yet no data have been obtained from children with diseases or injuries using the tests which would provide the ranges of identification scores that define hyposmic and anosmic individuals, and the equivalent ranges for those with gustatory dysfunctions. Clearly, this is a priority before the tests can be fully utilized by clinicians when diagnosing chemosensory dysfunctions.”

Forensic Pathology Device Sniffs Out Dead Air

“The Body Farm,” as the University of Tennessee Forensic Anthropology Facility has been known since inspiring Patricia Cromwell’s novel, was opened in 1971 by Dr. William Bass, who recognized the need for research into human decomposition after police repeatedly asked for his help analyzing bodies in criminal cases. What began as a small patch of land where one body was allowed to decompose in the open air for the sake of science has developed into a 3-acre complex that contains remains of around 40 individuals at any given time. Now, the Knoxville facility has been recruited by Orange County detectives for help in their continuing investigation into the disappearance of toddler Caylee Anthony.

After cadaver dogs responded to an odor emitting from the white Pontiac found abandoned by the child’s mother, Orlando investigators tapped The Body Farm for assistance in testing air samples from the trunk of the car. Using a sort of “artificial nose” which pulls air through a tube into a spectrometer chamber, the scientists will be looking for the presence of certain chemical compounds that are released only by a decomposing body. “After we die and the bacteria proliferate in our body and start breaking down our Read more

Flies That Can’t Smell just Can’t Tell

Just how important is a good sense of smell in matters of romance? Well, for male fruit flies, it’s so vital that the absence of just a single olfactory gene renders them as indiscriminate in matters of courtship as my cousin Freddie (no offense, Freddie).

Scientists at Duke University Medical Center have found that male fruit flies without the gene Gr32a, a critical pheromone receptor, were sexually outperformed by four to one in comparison with normal male competitors. They also tended to court females which had been doused with male pheromones, behavior not observed in normal fruit flies because females which smell of male pheromones have presumably already mated. In fact, the hapless Gr32a-impaired flies were just as happy to court the male competitors themselves.
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Lemurs are Double-Dealing Little Stinkers

Considering the important role of scent in nature, it’s no surprise that many species have evolved some downright sneaky tactics to disguise, diminish, or enhance their odor footprints. Male pandas will urinate onto a tree while performing a handstand so as to leave the highest (thus most dominant) mark. Dogs, to the horror of their owners, tend to mask their scent by enthusiastically rolling in some of the most foul-smelling substances imaginable. Humans shell out millions to eliminate the natural odors of our bodies in favor of odors we consider more attractive.

Lemurs, though, distant primate cousins of ours who split from the family tree before the monkeys and apes parted ways, may well have cornered the market on sophisticated scent-treachery. According to a new study conducted by Leonardo Dapporto at Florence University, each of these bi-scentual little guys produces two completely separate scents–one from each hand–and these scents are as distinct from one another as that of two separate lemurs.

It’s a discovery unprecedented in scent research, and the question is still open as to why dual-odors would evolve in a single individual. One answer is offered by Ron Swaisgood, a behavioral ecologist at the Zoological Society of San Diego, who suggests the opposing scents may enable lemurs to mislead neighboring groups and predators as to the size of their colony. An even more intriguing possibility is that having two scents might allow the lemur to communicate through scent with a sophistication previously undreamed of, weaving complex tapestries of odor as varied as the shades an artist might create from two colors of paint.

Stench Soup and Other Winning Recipes

Betty Crocker, she’s not. And when the US Department of Defense approached Pamela Dalton of the Monell Chemical Senses Center to create a recipe for the Foulest Malodor on Earth, she took to the task with a devilish passion.
Her “Burnt Hair” formula smelled pretty bad. “Who Me?”–which combined natural gas odorant with a sort of spoiled mushroom aroma–was downright nasty. “Bathroom Malodor”–a fecal odor spiced with rotten eggs and decaying rodent–was disgusting enough to get Dalton cursed in several languages by her multi-ethnic test group. But it was a worst-of-the-worst proprietary blend that took the prize: “Stench Soup” smells so perfectly horrible that it sends the stomach lurching, the eyes tearing, and blows every other thought right out of the mind.
“That one takes over every aspect of your consciousness,” Dalton says proudly, adding that she can think of several uses for her stinky concoction besides non-lethal warfare. “Odors are one of the quickest ways to get people to move away from something. I’ve evacuated our building on several occasions because we’ve had an odor escape.”

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