Scientists help plants call in the cavalry


September 30, 2005

Scientists have shown they can enhance a plant's ability to signal for help when threatened by pests.

Plants constantly send signals that attract their pests' predators, a little-known tactic intended to improve the plants' survival. For example, when potatoes, lima beans, cotton and dozens of other plants are damaged or under attack, they produce complex organic compounds known as terpenoids.

The compounds attract predatory mites, parasitic wasps, spiders and aphids. Researchers call the predators "bodyguards." Some 500 pests are known to attack plants and each pest has 80 to 100 natural enemies, according to Marcel Dicke, an entomologist at Wageningen University in the Netherlands.

Understanding how such plant signaling works could lead to the production of crops that are better able to protect themselves against natural pests, reducing the need for insecticides, Dicke and other researchers say.

Dicke and other Dutch and Israeli researchers reported Sept. 23 in the journal Science that inserting a gene into some thale cress, a type of a mustard plant often used as a research model, triggered increased production of two terpenoids known to attract predatory mites.

When the researchers released the predatory mites into a circle of thale cress, they found that 388 of them went first to the modified plants that were producing higher levels of terpenoids, while 197 went for the wild plants.

The researchers say that the terpenoid compounds produced by the modified plants are not easy to synthesize and that producing crops with enhanced defensive abilities is still years away.

--Dennis O' Brien

Did you know?-- Atmospheric pressure influences weather. Low pressure can bring clouds and rain; high pressure, clear skies.

People's Pharmacy

What is a safe daily dose of Advil? What harmful side effects does it have, if any?

Ibuprofen (sold as Advil, Motrin IB and the like) is a nonsteroidal anti-inflammatory drug. Like other medications in this class, it can be irritating to the digestive tract. Such drugs may also cause dizziness, rash, ringing in the ears, fluid retention and higher blood pressure.

The recommended dose for over-the-counter use is one caplet every four to six hours up to a maximum of six pills (1,200 milligrams) in 24 hours. This dose should not be taken without medical supervision for more than 10 days.

I take aspirin for my heart. I bruise easily and get dark splotches on my hands and arms. Is there any connection?

Some people are very susceptible to this potential side effect. Please discuss this issue with your doctor.

I was recently diagnosed with an irregular heart rhythm called atrial fibrillation. The doctor prescribed Coumadin and Toprol XL.

I would like to know if my vitamins and other supplements would interact with these drugs. In addition to a B complex and multivitamin, I take vitamin E, vitamin C, selenium, garlic, Coenzyme Q10 and fish oil.

The blood thinner Coumadin (warfarin) can interact with dozens of drugs, foods and dietary supplements. For example, Coenzyme Q10 is also known as ubiquinone and is related to vitamin K. It may reduce the effectiveness of Coumadin and lead to a blood clot.

Vitamin E, garlic and fish oil have modest anti-coagulant activity. That means they might increase the risk of bleeding when combined with Coumadin.

In their column, Joe and Teresa Graedon answer letters from readers. Write to them in care of King Features Syndicate, 888 Seventh Ave., New York, NY 10019, or e-mail them via their Web site:

Pluto probe in final tests

Space: Exploration

NASA's first unmanned mission to Pluto has begun with a spin on the Capital Beltway and a manned flight from Maryland to Florida.

The New Horizons spacecraft, designed and built at Johns Hopkins University's Applied Physics Laboratory, was trucked last week from the Goddard Space Flight Center in Greenbelt to nearby Andrews Air Force Base, then flown to Cape Canaveral aboard a C-130 transport plane.

Final flight testing began this week at the Kennedy Space Center for the next leg of the journey - from Earth to Pluto - now scheduled to start on Jan. 11.

Scientists hope the half-ton machine will fly past Pluto and its moon Charon - now 2.88 billion miles from Earth - in 2015. A suite of seven instruments will study the two objects' geology, surface conditions and composition, seeking clues to the origins of the solar system.

Mission controllers at APL hope to guide New Horizons beyond Pluto to explore other rocky or icy objects orbiting in the outer solar system. Pluto, the most distant planet from the sun and the hardest to reach, is the only one in the solar system that has not been visited by a spacecraft from Earth.

-- Frank D. Roylance

Fast track for ALS drug

Medicine: Research

Regulators have agreed to put an experimental treatment for amyotrophic lateral sclerosis, known as Lou Gehrig's disease, on a fast track toward approval, the maker said.

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