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Senior Tracy Adams concentrates on pipetting the DNA.
“The fire ant is a unique point of interest, especially among children,” explains Rob Rockhold, a scientist and administrator at the University of Mississippi Medical Center who has studied fire ant venom and conjured the Muse of Fire name from his college literature classes. “It also became obvious to us that fire ants just opened up a world of scientific disciplines.”
Rockhold, who oversees the fire ant project with colleague Donna Sullivan and MBL scientist William Reznikoff, says the Muse of Fire project speaks directly to students and will enable them to learn about subjects ranging from molecular biology and environmental science to toxicology and human health.
Teams of scientists and teachers met last summer in Jackson to develop the coursework and a variety of experiments. Then each of the five high school teachers tested one part of the curriculum in a class to make sure the lessons moved students beyond fire ants to wider biology concepts. Some teachers took their students to fields filled with tall grass to observe how fire ants affect other insects in their local environment. Others devised experiments that allowed students to understand how fire ants prey on their victims—in this case, crickets—by using venom substitutes to determine the concentration of a fatal dose.
This past fall, McKone incorporated elements from Muse of Fire in Bogue Chitto's first biomedical research course. One September afternoon, she led seven seniors to a sandy area just outside the cafeteria that serves the school of 630 students. Although they searched for fire ants, their real quarry that day was a type of bacteria called Wolbachia, which lives inside the ant. Their goal? To determine whether Mississippi fire ants are infected with Wolbachia and, if so, the prevalence of the bacteria.
Wolbachia are complicated critters. They infect spiders and many insects, influencing their reproductive behavior in a variety of ways. For example, the bacteria can cause all an insect's offspring to develop as females or allow only infected insects to reproduce. The bacteria live inside insect cells and are passed from generation to generation through the eggs. Wolbachia may also play a complex role in human diseases such as river blindness.
“The interesting thing is that one can use fire ants and other insects as investigative tools to find out if only some of them are infected with Wolbachia and why,” says Reznikoff, who helped McKone design the Wolbachia portion of the fire ants project.
Back in McKone's large, bright classroom, the seven students huddle in three groups, smashing ants with the sealed end of a pipette tip. They make sure to crush the ant's abdomen, where Wolbachia are typically found. The next step comes straight from a molecular biology textbook: finding the bacterial DNA (if it is present) inside the fire ant cells. Using polymerase chain reaction machines borrowed from Florida A&M University—the same thermal cyclers that so puzzled McKone in 2005—the students go through the step-by-step process of extracting the DNA samples.
McKone occasionally stops to quiz the students on what they're doing, making sure they know what each chemical does or why they are heating up the sample. “They love it. They like understanding why.”
Photo: Tom Roster