Behind closed doors in the Loeb Laboratory at the Marine Biological Laboratory is what might seem an unusual operation in a facility largely known for marine science: the National Xenopus Resource, in which scientists are raising thousands of frogs.
The animals will be used by scientists around the world whose research could someday result in medical breakthroughs for humans.
At different stages in life, the frogs have the ability to regenerate body parts, including arms, legs, and eyes. Joshua Hamilton, chief academic and scientific officer at the MBL, believes studying the frogs will one day have a direct benefit to humans.
“They regenerate body parts, which we can’t do,” Dr. Hamilton said. “If you really want to figure out how to have regeneration in humans, you have to figure it out by studying animals that actually do it. How do they do it and why don’t we?”
Dr. Hamilton believes the breakthroughs will come, although they may be decades away. Other scientists use the frogs to study cancer, cell, molecular and developmental biology. “We think there’s a lot of direct application to clinical medicine,” Dr. Hamilton said.
Behind closed doors in the Loeb Laboratory, Marko Horb, director of the National Xenopus Resource, led a tour of the operation yesterday. Fertilized eggs no bigger than the head of a pin grow in a few days to the size of a grain of rice. In weeks the tadpoles have grown legs and swim inside tanks. Ultimately the frogs will grow four to six inches long and live eight to 10 years, Dr. Horb said.
If you really want to figure out how to have regeneration in humans, you have to figure it out by studying animals that actually do it. How do they do it and why don’t we?
Dr. Joshua Hamilton
The frogs are Xenopus laevis and their smaller cousin, Xenopus tropicalis, claw-footed aquatic frogs from South Africa. The use of these species of frogs in science dates back to the 1930s, when a researcher in South Africa discovered that if the urine from a pregnant human woman was injected into a frog, it laid eggs. Using that knowledge scientists developed a pregnancy test that was used for the next 40 years. The discovery also led to the proliferation of frog-based research. Now the frogs are used in the same ways as lab rats as a major model organism.
“Frogs have all the same body parts as we do,” said Dr. Horb. He oversees three employees of the National Xenopus Resource. In his own research as an associate scientist in the Bell Center for Regenerative Biology and Tissue Engineering, he studies how the frog can turn a liver into a pancreas. By examining the changes in the cell, he hopes to be able to understand how to create cells that secrete insulin, which could have implications for treating diabetes.
Scientists can manipulate the Xenopus genes to create nearly any result, including changing the color of body parts. One strain has green eyes that show up under a black light. Scientists can also order the frogs customized to their specifications. “We can put in or take out any gene they want,” Dr. Hamilton said.
The frogs grown in Woods Hole are sold to researchers around the world for $35 to $45 each, Dr. Horb said. The National Xenopus Resource began selling frogs last year and have so far sold about 300. “We hope to sell many more than that,” Dr. Horb said. There are about 4,000 frogs in the resource now, which will ultimately increase to between 8,000 and 10,000, Dr. Horb said.
Before the National Xenopus Resource, various strains of Xenopus frogs were spread around the country in different laboratories. If a lab closed, the Xenopus strain could be lost forever. As the North American home for Xenopus strains, Woods Hole provides a service to the scientific community, Dr. Hamilton said.
The MBL is also home to workshops and annual meetings for Xenopus researchers. The National Xenopus Resource was established in 2010 through funding from The Eunice Kennedy Shriver National Institute of Child Health and Human Development and the National Center for Research Resources.