Like the “canary in the coal mine,” the worldwide decline of amphibian populations, including frogs, toads and salamanders, during the past 50 years may be a harbinger of emerging infections and environmental changes that endanger humankind, as well.
Just as important, some amphibian species have begun to recover from the global spread of a fungal infection called chytridiomycosis that caused the extinction of others. Their resilience suggests that our slimy friends may hold a secret to survival.
Louise Rollins-Smith, PhD, is a professor of Pathology, Microbiology and Immunology at Vanderbilt University Medical Center who studies the immune defense mechanisms of amphibians.
In “Climate is Us,” the current episode of VUMC’s original podcast series, Vanderbilt Health DNA: Discoveries in Action, she describes how, “from fishes and amphibians on up, we all have a very similar immune system.”
Their immunity, like ours, is being tested — not only by pandemics, but by climate change. “Amphibians are entirely dependent on water,” she pointed out. “If there are periods of drought, that’s going to stress them. That’s going to alter their immune defenses … They are going to struggle.”
Many frogs have specialized granular skin glands that contain pain-killing agents, anti-microbial peptides and toxins to ward off predators, Rollins-Smith said. Some of these agents have therapeutic potential in humans, for example, to heal diabetic foot ulcers, kill antibiotic-resistant bacteria and neutralize viruses.
That’s why it’s so important to understand the decline, and recovery, of amphibian populations. If a species becomes extinct before its “biological medicine cabinet” can be discovered and studied, she warned, “then it’s lost forever.”
Rollins-Smith is one of several US investigators who are participating in the new “Resilience Institute Bridging Biological Training and Research,” launched last month with a five-year, $12.5 million grant from the National Science Foundation.
Based at the University of Pittsburgh, the institute also includes the University of Alabama, University of California, Berkeley, University of California, Santa Barbara, University of Massachusetts Boston, University of Mississippi, University of Nevada, Reno, Temple University, Texas Tech University, and the University of Tennessee.
Field teams in northwest Pennsylvania, the Sierra Nevada mountains in California, Panama, and Brazil will monitor how frogs and toads are rebounding in each location to better understand the paths that recovery can take.
“Our role at Vanderbilt is to receive biological samples, primarily skin secretions and fungal isolates from these field sites, and study the immune defenses of the recovering species,” Rollins-Smith said.
“There is also a significant educational component of this institute research,” she added. “Our laboratory will host both undergraduates and high school students as part of the Medical Center’s ‘Aspirnaut’ program, and we will support undergraduate research through the Department of Biological Sciences.”
Founded in 2006 by VUMC faculty members Billy Hudson, PhD, and his wife, Julie Hudson, MD, MA, Aspirnaut is a summer research program that to date has helped nearly 300 high school and college students from 30 states prepare for careers in science and health care.
“There’s a lot of recognition among young people that there is a climate crisis,” Rollins-Smith said. “I hope that encourages them to develop careers in science, so they can begin to help find the solutions.
“The great diversity that we have in terms of animals is not a permanent thing,” she warned. “It needs to be protected.”
