Fireflies Are De-Lighted To Serve Science At OSU
By Fred Causley
STILLWATER--Some "illuminating" research is being conducted at Oklahoma State University as biochemists seek to understand more about the processes that cause those little "lanterns" to light up in fireflies.
Why? What for? Who cares?
Because the enzyme, luciferase, that produces the reaction inside a firefly also will cause the emission of light when confronted with the adenosine triphosphate (ATP) from bacterial cells. The result is a way to measure for the presence of germs on a very small scale.
"What nature intended as a means of arranging sexual encounters between consenting fireflies has become the basis of a whole field of analytical biotechnology," said Franklin Leach, professor and researcher in OSU's department of biochemistry and molecular biology.
Leach recently returned from England where he gave a talk at "ATP 96," a symposium where 160 scientists from all over the world met to discuss ATP and bioluminescence, or "lighting up" the natural way.
OSU has been on the front line of bioluminescence research for several years because of the work of Leach and his associates. They frequently go out and catch their own fireflies to obtain enough luciferase to conduct their research.
Once they have enough fireflies, they freeze them, dissect off the "lanterns," grind them and isolate the messenger ribonucleic acid (mRNA)
"The mRNA is like a blueprint the cell uses to construct the enzyme which causes the flashing," Leach said.
"If you take it out and put it into a bacteria, the result will glow on a gel plate in the laboratory."
Leach and his associates sequenced nucleotides in the mRNA, enabling them to figure out its amino acid patterns in the gene code. It turned out that three letters on the mRNA blueprint stands for one amino acid. The protein comprising the enzyme is made up of these amino acids.
Leach explained that all living plants and animals make and use ATP in their cells daily. "A 180-pound person makes and uses 180 pounds of ATP each day. If you had to buy that commercially, it would cost six million dollars," Leach said.
The overall goal is to determine how fireflies make their light and to improve the luciferase that causes the reaction. By improving its stability, or "shelf life," more material will be available for testing at a lower cost.
The firefly enzyme has various medical applications, such as determining the number of bacteria in blood or urine. Health applications include rapid and accurate measurements of bacteria in milk, orange juice, water and other foods.
"In meat processing plants, this technology could be used to be sure bacteria have been eliminated from equipment prior to putting the next batch through. Some 10 million tests a year are required in that industry, so you are talking about big business," Leach said.
Leach and Li Ye, a graduate student at OSU, submitted the mRNA they sequenced to an international gene bank at the National Institute for Health, in Maryland. Now, anyone working on firefly luciferase can retrieve their data on the Internet. Since firefly luciferase differs from one species to another, this enables species identification and helps prevent duplication of effort.
While at the ATP 96 meeting in England, Leach learned that British scientists had figured out the three- dimensional structure of the firefly luciferase.
"Now we have to learn how it all fits together," Leach said. "We know the molecule is 546 amino acids long, but how it changes shape during the course of a reaction is not known. We cloned it to show we had the right combination, but we still have to know more in order to determine how it works.
"Since ATP is the universal currency of energy, this work offers the possibility for the detection and characterization of fundamental life processes. All of the work done on it worldwide to date is but the tip of a very large iceberg."
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