Jellyfish Find Their Status Elevated

HOUSTON - Dorothy Spangenberg has done for jellyfish what Don King did for boxing.

It was her idea to send the tiny creatures into space aboard the space shuttle Columbia.

The main purpose of the mission, which ended June 14, was to study how humans adjust to weightlessness and re-adapt to gravity. But the image of almost 2,500 jellyfish hurtling through space is what was captivating.

By comparing jellyfish raised in space with those raised on the ground, Spangenberg hopes to learn how weightlessness affects development and behavior. The jellyfish might even provide clues about how space flight affects the gravity sensor in the inner ear of humans.

Thanks to Spangenberg, jellyfish have experienced a rise in popularity almost as high as their orbit around Earth. No longer just ugly blobs that muck up beaches, jellyfish are now scientific pioneers.

Spangenberg - believed to be the only jellyfish researcher at a medical school - says she isn't surprised about the public's fascination with her charges. "I wouldn't be, because I think they're wonderful."

Like most people, however, Spangenberg used to think jellyfish were more annoying than noteworthy. They hid the seashells she liked to collect on the beaches of Galveston, her hometown.

Her attitude changed 30 years ago while studying for a Ph.D. in developmental biology at the University of Texas at Austin.

"I have always been interested in factors that control development, that influence development," said Spangenberg, a research professor in the pathology department at Eastern Virginia Medical School in Norfolk.

Their simplicity makes jellyfish perfect research subjects.

"There's all this wonderful development that takes place in such a short period of time," Spangenberg said. "I can't study speech patterns or things like that, but for those of us who are interested in things at the cellular level, the simple animals have a lot to offer."

She became fascinated by a particular stage of development that takes only five or six days: the metamorphosis from polyp, the larval stage, to eight-armed ephyra, a free-swimming creature no bigger than a gnat.

She likes to wear a custom-made medallion in the shape of an ephyra and carry a small flask filled with the creatures.

"They're quite different from what most people think of jellyfish," Spangenberg said. "You're not apt to see these on the beach. They're very tiny."

Only a person with a trained eye can spot the transparent baby jellyfish. Spangenberg collected her first polyps on Corpus Christi beaches.

She spent five years investigating how to make polyps evolve into ephyrae on demand. She discovered that adding iodine to their water stimulated polyps to produce the thyroid-type hormone needed for metamorphosis. "In nature, the iodine is in the sea water all the time," she said.

When planning the first space mission devoted to biomedical research, the National Aeronautics and Space Administration became interested in jellyfish for the same reasons as Spangenberg did.

The creatures' ability to develop rapidly made them good candidates for study on a relatively short mission. Even more important, the metamorphosis of polyp to ephyra included the development of gravity sensors that - in a primitive way - resemble the one found in the human inner ear. These sensors - special crystals in sacs at the tips of the ephyra's arms - help jellyfish orient themselves in water.

Spangenberg designed an experiment to see how weightlessness affects the jellyfish's gravity sensors or any other aspect of their development or behavior.

Both polyps and ephyrae flew aboard Columbia in slightly less than three quarts of water. Their aquarium sat in an incubator the size of a small microwave, heated to 82 degrees Fahrenheit.

Crew members induced polyps to metamorphose into ephyrae by injecting iodine or a thyroidlike hormone into their water.

Mission specialist Tamara Jernigan videotaped the jellyfish several times during the nine-day mission. Spangenberg got a brief glimpse of an ephyrae video.

"I think one of the aspects of this whole experiment that is exciting to me is (that) we have already established that the animals survive launch," she said. "They're moving and pulsing."

On the ground, Spangenberg taped another group of polyps and ephyrae at precisely the stage of development as their high-flying counterparts. She will compare the tapes to study differences in behavior. That study is "one of the most interesting aspects of the experiment."

Spangenberg and her team have been examining the ephyrae at Edwards Air Force Base in California. They counted the number of crystals in four of each ephyra's arms. They counted the number of arms to "see if they have all their parts."

Although the jellyfish might hold some clues as to what happens to humans in space, "I extrapolate very carefully," Spangenberg said. "We're a long way from a fully developed human being." -------------------------------

HOW THE JELLYFISH EXPERIMENT WORKS By comparing jellyfish raised in space with those raised on the ground, Dr. Dorothy Spangenberg and other scientists hope to learn how weightlessness affects development and behavior. The creatures' ability to develop rapidly makes them good candidates for study on the relatively short space shuttle mission. The baby jellyfish also develop gravity sensors that resemble the one found in the inner ear of humans. Scientists hope the jellyfish experiment will provide clues about how space flight affects the human gravity sensor.

STEP 1 Jellyfish polyps were flown aboard the space shuttle Columbia in slightly less than three quarters of water. Their aquarium sat in an incubator the size of a small microwave, heated to 82 degrees Fahrenheit.

STEP 2 Astronauts induced the polyps to grow into ephyrae, which pulse as they swim. The pulsing action is intended to keep ephyrae from sinking, but since there was no danger of that in space, they appear to swim in circles.

STEP 3 Scientists were closely monitoring the development of the ephyrae gravity sensors, known as statoliths. These sensors - special crystals in sacs in the ephyrae arms - help jellyfish orient themselves in water.

Source: Dallas Morning News