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November 22, 2013
CONTACT: K.E. Schwab

Researchers examine cell regeneration

SLIPPERY ROCK, Pa. - Who would have thought that a small worm, less than an inch in length found in streams on the Slippery Rock University campus and around the world, might someday provide answers to re-generation of human body parts?

Simon Beeching, SRU professor and a number of undergraduate students did and they are now searching for the answers using brown planaria, a simple flatworm organism.

Talking from his Vincent Science Center lab, Beeching explains the campus research starts with research already confirmed by the black planaria, close cousin of the brown planaria in the animal kingdom.

"The brown planaria, which is less than an inch long, but can be spotted in the streams on campus and all over North America. We are looking at how the brown planaria know how to avoid an area of their habitat where another of their species has been injured and how they can regenerate their bodies," he said.

"We have been able to replicate experiments done with the black planaria using the brown species to show that the worms can tell when one of their own has been hurt. We don't know if it is chemical cues, if they can 'smell' it, or if there is some other factor. This 'avoidance' behavior has been clearly demonstrated in one species of flatworms, and we have now extended the research to a second species," he said.

Beeching and his student biology researchers have collected the brown planaria from campus streams for their work. He said there are distinctive physical differences in the two species, "but, either way, they are very simple animals."

"There is a general term for these kinds of chemical cues called an "alarm substance," he said. "We are not sure exactly what it is, but it is known in a number of fish and snail species as well. For example we have seen that in a school of fish, when one fish is attacked by predator, the other fish do not need to see or hear the attack, but can detect it, possibility through chemicals excreted by the tissues of the attacked fish."

"In general, it appears that some chemical compound, the alarm substance, within the tissues is released on injury and detection of those chemical produces escape or avoidance in those detecting it. Researchers demonstrated this alarm substance in a simple flatworm, the black planaria, for the first time in 2000, and went on to demonstrate impressive learning in these simple animals using these chemical cues," he said.

Beeching, and a series of SRU undergraduates have been working on the topic and related issues for a decade.

"In our research, we found the brown planeria may be exhibiting similar behavior," he said. "Our experiment involved a basic procedure of taking one of the worms and grinding it up in water. We then put another worm in an aquatic medium and using a micropipette carefully add a small quality of the fluid. We then look to see any change in behavior. We found the second flatworm avoided the area after the medium was administered," Beeching said.

"Of course, we had to run a control, just to be sure of what we were seeing. We replicated the experiment, but this time adding only a small quantity of pure water, rather than the medium, and found the worm, in this case, did not avoid the area," he said.

"We call this an 'avoidance response," he said. We knew it had been shown in the black planeria, and we were able to show it in the brown planeria species too," he said. "We believe it has something to do with the worm's tissues, or the chemicals released when the tissues are broken."

"We suspect it will also apply to a number of other planeria species found around the world," he said.

"We hope to publish the results of our brown planeria research soon, he said.

"As a biology major I have a natural interest in research, specifically in animal science," said Kristyn Pristov, from Geneva, Ohio. "I have had Dr. Beeching as a professor for multiple classes. I contacted him about this research opportunity last year because I knew it would be a great experience."

"My interest in planaria arose in zoology when we conducted experiments on their ability to regenerate their bodies when cut. I found them a fascinating animal, such a simplistic nervous system, yet so complex in its abilities. The trials I am conducting involve the heterospecific response of one black planaria to two macerated brown planaria," she said.

"In this experiment it is my goal to determine if the concentration of heterospecific brown planaria affects the chemical alarm cue sensed by the black planaria. I am hoping that the results yield a positive result, meaning the black planaria exhibit avoidant behavior in the presence of two macerated brown planaria. This will help give us an idea on the relationship between the species and also if concentration matters," she said.

"I am extremely happy to be a part of this research and hope results from this year help lead us down a road of new discoveries. For me, research allows me to put all the things I have learned as a biology student to use. I am finally getting the chance to determine the significance of unknown events that occur in nature," Pristov said.

Others recently involved in the research are Jared Caroff, a biology major from Indiana, Pa., and now graduated from SRU Stephanie Case, and Shane Duda, who are both attending graduate school at the University of Mount Union.

Beeching said he believes "tissue regeneration is the future of medicine. There has been a resurgence of interest in these worms and their ability to regeneration. In one class, we presented a demonstration of the regeneration capability by decapitating one of these worms. It was able to re-grown its head, including eye spots, in six days - less than a week. The same was true of the head portion of the worm, which regenerated its entire body."

"We believe the flatworm's body is filled with as much as 50 percent stem cells, which are capable of becoming any body part if properly triggered," he said.

"If humans could regenerate organs, which we currently can't, it would be a huge step in medicine. We just have to figure out if it is possible - and how," Beeching said.

The flatworms can regenerate/reproduce both sexually, with traditional egg and sperm reproduction, and asexually, by simply dividing its body, he said.

"During the summer when the conditions are optimal and there is a lot of food, they reproduce asexually. When food is scarce and temperatures fall, sexual reproduction becomes common," Beeching said. "We had one flatworm in a dish, and it just cloned itself."

The long-term implications involve the use of stem cells and tissue regeneration.

Beeching said among the major benefits of stem cell and tissue regeneration could be in treating diabetes where human cells could be stimulated to again make insulin.

"They are already using stem cell regeneration in retinal tissues in eyes and for arthroscopic joint surgery to repair cartilage," he said.

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