Photo by Veer
Red-Eyed tree frog

Delving into the mysteries of the declining frog populations

Frogs around the world are in trouble. And as species are lost, so are their biological treasures.

The National Science Foundation has awarded a team of Vanderbilt University Medical Center investigators a four-year grant to study amphibian declines in Central America and California.

“Amphibian skin has long been favored in folklore for its medicinal properties,” says Louise A. Rollins-Smith, associate professor of microbiology & immunology and principal investigator of the new grant. “Frogs are a rich source of potentially useful molecules that might work against human pathogens.”

Rollins-Smith collaborated with Derya Unutmaz, M.D., assistant professor of Microbiology & Immunology, and other Vanderbilt scientists to show this month that compounds from frog skin block HIV infection.

	Photo by Douglas C. Woodhams
	The Golden Frog of Panama, Atelopus zeteki

“Frogs have evolved over millennia to combat such pathogens, so we want to learn from the frog as much as we can about these molecules,” she says.

With the new grant, Rollins-Smith and her team will be investigating the antimicrobial defenses of declining frog populations that are facing a particular skin fungus. Postdoctoral fellow Douglas C. Woodhams will be traveling to sites in Panama and in California to collect samples of the skin peptides from affected frogs.

“Our goal is to study frog populations that are ahead of an epidemic of this fungus, and those that are behind an epidemic to see if the ones that have survived have beneficial protective peptides,” Rollins-Smith says.

Photo by Doglas C. Woodhams
The Panamanian red-eyed tree frog, Agalychnis callidryas

The Mass Spectrometry Research Center at Vanderbilt is particularly valuable to the team’s studies. Using mass spectrometry, it is possible to characterize the array of peptides in the samples and rapidly focus on and sequence those that might be antimicrobial.

“We hope to figure out which species are most vulnerable to this fungal pathogen so that they can be the focus of greater conservation efforts,” Rollins-Smith says.

The studies may also reveal new antimicrobial peptides which could be useful blockers of human pathogens, she added.

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Louise Rollins-Smith’s home page

ImmuneMatrix, the Unutmaz Laboratory website