The tubeworm, a marine organism, is not a likely creature to be researched at a landlocked university such as Penn State.

However, Jason Flores (graduate-biology), part of a Penn State research team, currently is studying tubeworms near hydrothermal vents in the East Pacific Rise, about 300 miles west of Panama.

Flores, along with researchers at Penn State and the University of Massachusetts, recently discovered how Riftia pachyptila's hemoglobin binds hydrogen sulfide, a byproduct of the hydrothermal vents, he said.

The worm's hemoglobin could be used as "a model for a blood substitute for humans," Flores said.

Some researchers have tried using earthworm hemoglobins but they are too large, he said. Riftia's hemoglobin is simpler, smaller and could be mass-produced more easily, he said.

However, Flores said that if research were started today, it would most likely still be another 10 years before Riftia's hemoglobin could be used as a human blood substitute.

Riftia live 2,500 meters below the surface of the ocean near hydrothermal vents, he said.

Breea Govenar (graduate-biology), a team researcher who also studies Riftia, said the organism's survival is dependent upon its proximity to hydrothermal vents. The worms can grow up to two meters long, she added.

Since Riftia have no means of producing their own food, they form mutually beneficial relationships with bacteria, Flores said. The bacteria are dependent upon the worms for nutrients such as oxygen and hydrogen sulfide for their metabolic functions, he said.

Riftia exchange gases through their plume, a gill-like structure on the end of their body, Flores said.

"A plume is like their lung where oxygen, sulfide and carbon dioxide diffuse across," he said.

The worm's hemoglobin transports oxygen to its tissues, while transporting both oxygen and hydrogen sulfide to the bacteria, Flores said.

Hemoglobin keeps the oxygen and hydrogen sulfide molecules apart so they do not spontaneously react, he said. Otherwise, the two would combine, rendering the oxygen useless to both organisms and allowing sulfide, which is harmful to Riftia, to reach the worm's tissues.

"The worms themselves could be poisoned by sulfide. The hemoglobin also acts to protect them," he said.

Researchers have been studying Riftia's hemoglobin for past 25 years, but it wasn't until 10 years ago that they thought they understood the sulfide binding mechanism, Flores said.

"We knew the worms had two large hemoglobin and that sulfides binded to them," he said.

Team member Susan Carney (graduate-molecular ecology), who was responsible for sequencing part of Riftia's hemoglobin gene sequence, said, "They found out what they had thought for years had been the binding mechanism was incorrect."

Flores said University of Massachusetts researchers mapped the densities of the electrons of the worm's hemoglobin using X-ray crystallography.

This technique is used to determine the 3-D structure of the hemoglobin, said Charles Fisher, professor of biology.

Knowing the genetic sequence of the hemoglobin and the electron densities, a computer program was able to map out the hemoglobin, Flores said.

"It ended up that zinc ions were discovered" by the program, he said. "We didn't know they existed in the worm's hemoglobin."

The shape of the worm's hemoglobin is a hollow sphere, whereas humans have globular-shaped hemoglobin, Flores said.

"Their smallest hemoglobin is eight times the size of ours and has six times the number of oxygen-binding sites," he said.

Flores authored a paper about his research that was published last month in the journal Proceedings of the National Academy of Science.

The research was funded by the National Science Foundation, National Institutes of Health, The Alfred P. Sloan Foundation and the National Oceanic and Atmospheric Administration's National Undersea Research Program.