|
Media
Contact:
Dr. Ralph Dewey,
919/515-2705
Paul K. Mueller,
News Services, 919/515-3470
Nov.
14, 2002
Gene Researchers
Close In On Nicotine's "Evil Cousin"
FOR
IMMEDIATE RELEASE
|
Nicotine
isn't all bad, despite its addictive qualities
and its presence in tobacco products, increasingly
taboo in these health-conscious times. As a chemical
compound, nicotine even has beneficial properties.
It's used around the world as a relatively cheap,
environmentally friendly insecticide, repelling
bugs that attack tobacco and other plants, and
- contrary to popular misconceptions - it is not
a carcinogen.
Take
a nicotine molecule and snip off a methyl group,
though, and you've got nicotine's evil cousin:
nornicotine. (A methyl group is one carbon and
three hydrogen atoms.) This truncated version
of nicotine, helped by certain tobacco-leaf microbes,
converts to nitrosamines - potent carcinogens
- during the tobacco-curing process. If researchers
could find the genetic location of the enzyme
that removes nicotine's methyl group, tobacco
with little or no nornicotine would be possible.
|
Dr.
Ralph Dewey
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That's
the task of Dr. Ralph Dewey, professor of crop
science in the College
of Agriculture and Life Sciences at North Carolina State
University. Working with select lines of Burley
tobacco, he and his colleagues are trying to isolate
the nicotine N-demethylase gene from among the 25,000
or so unique genes found in tobacco.
When
they're successful, says Dewey, they'll have achieved
several key goals. "One, we'll have created a large
genomic database. Two, we'll have the tools needed to
reduce the levels of harmful nitrosamines in Burley
tobacco. And three, we'll develop information that could,
perhaps, lead to alternate uses for this important North
Carolina crop."
Tobacco's
genome, however, is just now being investigated, so
Dewey and fellow researchers at the Genome
Research Laboratory on NC State's Centennial
Campus are faced with a painstaking process of elimination.
They do have a few clues, though. Nicotine changes to
nornicotine when tobacco is "senescing" -
getting old and turning yellow - so genes involved in
the aging process are getting a close look. They also
suspect that the chromosomal location of the culprit
gene is "unstable," or prone to transposition
or mutation, so such locations also warrant an interested
eye. And if they can verify that the gene is of the
type known as a "P450," they'll have narrowed
their search to about 500 genes - which is progress
in Dewey's line of work.
Dewey
also has access to the Genome Research Lab's microarray
technology, which automates and computerizes a process
once done by hand. Capable of placing up to 5,000 genes
on microscope slides and showing results on a high-resolution
scanner, the high-tech tool is speeding the search for
the unwelcome, nornicotine-triggering gene.
Funded
in part by the Philip Morris Companies, Dewey's research
is a modest but important part of the larger Tobacco
Genome Project ongoing at NC State's Genome Research
Lab. Recognizing the huge role that tobacco plays in
North Carolina's - and other states' - economy, and
the need to both reduce its toxic compounds and find
more uses for the crop, Dewey and his colleagues methodically
pursue their quarry in the daunting molecular realm.
Their efforts are largely unheralded, and success -
so far - is elusive. But the days of nornicotine, nicotine's
ominous cousin, are probably numbered.
-
mueller -
|
Raleigh,
NC 27695
