Regeneration Research : 8-Legged Frog Has UCI Hopping
Strange frogs that have grown as many as eight legs are being studied at UC Irvine, and the long-range results may help to improved medical care to humans, UC Irvine biologist Stanley Sessions said Wednesday.
Sessions is among the biologists at UC Irvine who specialize in studies of regeneration--regrowth of body parts. “Study of regeneration can have benefits for humans,” Sessions said. “Study of regeneration is study of growth, and cancer, for instance, is uncontrolled growth.”
Because of UC Irvine’s national reputation in regeneration research, the university last summer received some rare, extra-legged tadpoles found in a pond in Santa Cruz County.
Stephen B. Ruth, a teacher at Monterey Peninsula College, discovered the unusual tadpoles last summer while making studies of the pond. He found that 70% of the Pacific tree frogs in the pond were growing extra legs, and some had as many as eight limbs.
“Dr. Ruth sent some of the tadpoles to UC Irvine because of our regeneration work,” Sessions said.
Parasite Eggs Found
The cause of the extra legs on the frogs still must be precisely determined, but Sessions said the apparent reason is that “there are eggs of some kind of parasite in the tissue at the base of the limbs.” He said the parasites may have triggered the frogs to grow extra limbs.
“Frogs can regenerate limbs during larvae, but they lose that ability after larvae,” Sessions said. “Salamanders keep that ability to regenerate all their lives.”
The uncommon thing about the Santa Cruz County frogs, Sessions said, “is that it’s unusual for frogs spontaneously to regenerate limbs; usually they regenerate because of injury or loss of a limb.”
Ruth, the Monterey Peninsula College professor who first found the strange frogs, has tested the pond water and found that it is not polluted, Sessions said. So UC Irvine biologists now will try to identify the parasite eggs found in the frogs. He said that knowledge will help the growing body of information about what causes growth and regrowth.
Ultimately such knowledge can be put to use for humans, he said. “Humans have limited regeneration” capabilities, he said. “Parts of the liver can regenerate. And in some cases, tips of fingers that have been severed can grow back.” Skin also grows back, and Sessions said that it was in this area that regeneration study has potential for helping burn victims.
In short, Sessions said, the study of the extra-legged frogs has more implications than may be readily apparent.
“By looking at the pattern of that (frog leg) growth, we may determine a method used to produce regeneration,” Sessions said. “This sort of thing could be very important.”
