| NEW YORK (AP) - For the first time, scientists have
apparently identified one of the tiny taste bud sensors that
let people detect sweetness in foods.
The work could lead to improved artificial sweeteners, and
maybe help explain why some people have a sweet tooth.
Researchers have actually identified a gene, present in
mice and people, as the blueprint for a ``receptor'' in taste
buds. It's not yet proven that this receptor detects
sweetness, but the researchers said the evidence is strong.
``We feel this is an excellent candidate for a sweet
receptor,'' said Linda Buck of the Howard Hughes Medical
Institute and Harvard Medical School (news
- web
sites).
She and colleagues, including postdoctoral fellow
Jean-Pierre Montmayeur, who found the gene, report their work
in the May issue of the journal Nature Neuroscience.
Dr. Robert Margolskee of the Hughes institute and the Mount
Sinai School of Medicine in New York, said he also believes it
is a sweet receptor. His group reports their findings in the
May issue of the journal Nature Genetics.
A biologist familiar with both papers agreed. ``The
evidence is pretty strong,'' commented Stuart Firestein of
Columbia University.
Susan Sullivan, a research fellow at the National Institute
on Deafness and Other Communication Disorders, said she has
also identified the gene and will publish her work shortly.
Scientists believe people have more than one sweet
receptor, allowing them to detect sweetness in a variety of
food substances. If the newly identified receptor is for
sweetness, it might be used to develop better artificial
sweeteners that taste more like sugar, Margolskee said.
He also speculated that different versions of the gene
might make people more or less sensitive to sweet taste, and
so give some a sweet tooth. ``Maybe it explains someone who
takes two lumps of sugar in their coffee, as opposed to one
lump or no lump,'' Margolskee said.
If so, the gene may play some role in promoting obesity, he
said.
To find the gene, both teams followed up on a prior finding
in mice. Some strains are less sensitive to sweet taste than
others, and scientists had found the approximate location of
the responsible gene on a mouse chromosome.
In the new work, the scientists surveyed that region of the
mouse chromosome and the corresponding region of human DNA,
eventually identifying a gene that looked like it could give
rise to a taste receptor.
They also found that sweet-sensitive mice had different
versions of this gene than sweet-insensitive mice had.
Margolskee's group proposed how a version found in insensitive
mice might lead to a malfunctioning receptor.
The scientists found that, in both mice and people, the
gene is active only in taste bud cells known to contain taste
receptors.
But it will take more work to nail down the idea that the
gene gives rise to a sweet receptor, Buck and Margolskee said.
Sweetness is one of five recognized tastes. Genes for
apparent bitter taste receptors were identified by Buck and
others last year. Salty and sour tastes are detected by a
different kind of sensor, and the identity of the
sour-detecting system isn't yet known for sure.
A fifth taste, called umami, is found in the flavoring
monosodium glutamate and many protein-rich foods like meat,
fish and cheese. Researchers reported last year that they'd
found a probable umami receptor. |