22 February 2011

Mag Lab researcher discusses "Sex in the Soil" at March 1 Science Café.

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It may be the battle of the sexes above ground, but below the surface, it's a different story. File it under Strange but True: Mere inches beneath our feet, a multitude of hermaphrodites — creatures with both male and female sex organs — live an outlaw lifestyle (by above-grounders' rules, anyway).

The risqué little bandits are roundworms, and they are nothing like the fat, squiggly earthworms gardeners welcome into their soil. Roundworms — also known as nematodes — are often only a millimeter long and invisible to the eye. They are so prolific, however, that four of every five animals on the planet is a nematode. Just ask Art Edison, who knows more about these abundant creatures — the good, the bad and the mysterious — than anyone you'll meet.

He'll host a lively "Sex in the Soil" conversation on nematodes at the March 1 Science Café at Ray's Steel City Saloon, 515 John Knox Road. Be there by 6:15 p.m. to grab a seat; the discussion will last until 7:30 p.m.

"A huge percentage of what we know about human health is really from studying model organisms like the worm," said Edison, a biochemistry professor at the University of Florida and the Mag Lab's director of chemistry and biology. "They're fascinating animals."

Among the surprising discoveries he and others have learned about a particular nematode, C. elegans, is its ability to lengthen its lifespan and alter its libido. Such findings could one day hold the key to increasing our own longevity and libido.

"What we're doing now," Edison said, "is trying to learn the chemical language of how these worms talk to each other, how they communicate."

Researchers know that nematodes communicate by secreting substances called pheromones. If there's not enough to eat, for example, they secrete a pheromone that triggers mass hibernation. Strangely enough, a smaller secretion of that same pheromone triggers instead a change in libido.

Hermaphroditic worms that sense via pheromones that males are available to mate with, will seek out a male rather than self-reproduce, Edison said. When C. elegans self-reproduces, she lays about 100 eggs, almost all hermaphrodites. If she mates with a male, she lays about 300 eggs: half will be males; half, hermaphrodites.

Edison, whose research has taken him to the Amazon and Peru , will also touch on the dark side of nematodes. Some of the more than 28,000 identified species are highly destructive parasites. The heartworm nematode, for example, preys on our pets. Hookworms prey on millions of children and adults, especially in developing countries. Although rarely fatal, a heavy hookworm infection can stunt a child's growth and cause intellectual retardation.

And while some nematodes benefit the soil, there are other types that destroy the roots of crops. Many a Tallahassee gardener has watched her tomato plants turn yellow, keel over and die, killed by parasitic nematodes.

"There are billions of dollars of crops lost each year to nematodes," Edison said.

One day, he hopes his research will help address these problems.

"We want to learn how to control these things. If we can figure out how they talk to each other, we can come up with a much better strategy to control them."