STORY LEAD:
Iron-Hungry Compound Can Glow as Satisfaction Grows
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ARS News Service
Agricultural Research Service, USDA
May 14, 1999
Ben Hardin, (309) 681-6597, bhardin@asrr.arsusda.gov
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Detecting trace levels of iron in biological samples within two minutes is
now possible with a new procedure developed by Agricultural Research Service
scientists.
In the new procedure, the scientists used a special chemical, called a
pyoverdine, produced by the beneficial bacterium Pseudomonas fluorescens.
Pyoverdine can be used to create a biosensor. Biosensors, which rely on
living organisms or their by- products to identify and gauge chemical
concentrations, can be immersed in liquids and monitored by computers.
Under ultraviolet light, the pyoverdine normally takes on a yellow greenish
glow that quickly subsides as iron is absorbed. But the researchers saw a
strikingly different scene when they mixed a solution, called an acetate
buffer, with the pyoverdine and then added the combination to test samples
containing as little as 10 parts per billion iron. Instead of quickly
subsiding, the glow steadily increased for several minutes. The more iron
present, the slower was the rate of increase.
The researchers have applied for a patent on the iron detection method.
Now, ARS is seeking an industrial partner to develop the pyoverdine-acetate
combination for an analytical process known as kinetic fluorometry. For
example, in some parts of the world, a simple kit might be used to monitor
increased iron levels in urine as patients are treated with an antimalarial
drug. Or someday more sophisticated tools, fiber-optic biosensors, might
monitor iron during water, food, pharmaceutical and chemical processing.
ARS is the U.S. Department of Agriculture's chief research agency.
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Scientific contact: Patricia J. Slininger, ARS, National Center for
Agricultural Utilization Research, Peoria, Ill., phone (309) 681-6286, fax
(309) 681-6427, slininpj@mail.ncaur.usda.gov.
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