By: Emily Huegler
“Amphibian rate of extinction is at such a high level right now that people are calling it the sixth mass extinction,” Fordham junior Jennie Wuest explains. In Dr. J.D. Lewis’ microbial ecology lab, Wuest is working to figure out a potential way to slow this extinction.
Amphibian species are in danger for two main reasons: urbanization and infection by a fungus called Batrachochytrium dendrobatidis (Bd). Bd attacks amphibians’ skin, preventing respiration and essentially causing them to suffocate. In urban areas, the effects of Bd on amphibians are worsened.
Wuest studies eastern red-backed salamanders, a species resistant to Bd — even if they contract Bd, they are not susceptible to it. This immunity is thanks to the salamanders’ cutaneous microbiome, i.e., the bacteria, fungi, and other microorganisms living on their skin. Although much research has been done on the interactions between the bacterial microbiome and Bd, Wuest is among the first to hypothesize that it may be another fungus on the salamanders’ skin that is preventing Bd from functioning.
Wuest’s hypothesis stems from the fact that fungi on the salamanders’ skin must compete with Bd for habitat space and other resources. The fungal microbiome is not only more closely related to Bd than bacteria, but it has also been shown to play a role in amphibian disease. If there are species of fungi that inhibit Bd growth, Wuest’s experiment will identify them.
The project consists of three parts: identifying what fungi are present in the eastern red-backed salamanders’ skin microbiome, determining if these fungi can stop or slow Bd’s growth, and finally, analyzing the interactions between the identified fungi, Bd, and bacteria to simulate a more realistic environment.
Beginning in the fall of 2019 with the first part of her experiment, Wuest swabbed the salamanders’ skin in six locations around New York City (one of her favorite parts of the research process, because the salamanders are adorable). In the lab, she isolated and amplified the DNA of the fungi on the swabs before sending it out to be sequenced and identified.
Now, despite COVID-related delays, she is progressing smoothly through the second part of her experiment. To determine if any of the identified fungi can prevent the growth of Bd, Wuest is culturing Bd together with the anti-fungal metabolites produced by the isolated fungi. These anti-fungal metabolites are the substances that could be the sources of their inhibitory effects against Bd. Wuest will measure the growth rate of Bd in the presence of each different fungal species’ metabolites to determine their individual interactions.
As one of the first in the field to study interactions between amphibian fungal microbiomes and Bd, Wuest has had to overcome many difficulties in the lab. “Fungi are more difficult to grow in an artificial environment than bacteria,” Wuest states. It has been a challenge to create an environment where both Bd and the other fungi grow well. Wuest cites Dr. Elle Barnes and graduate student Steve Kutos, fellow members of Dr. Lewis’ lab, as being “instrumental in developing the procedure” she has been implementing.
The end goal of Wuest’s research is to transplant beneficial microbes from species like eastern red-backed salamanders to species that lack these microbes. In this way, her results could be incredibly useful in preventing the further spread of Bd and even in saving countless amphibians from extinction. Preservation of these vertebrates is “especially important because amphibians are indicator species of how the environment is doing.” They live in the soil and the water, connecting different ecosystems and playing an integral role in ecosystem health. Their extinction would have profound consequences.
Wuest takes great interest in the intersection of wildlife conservation and microbial ecology. She thoroughly enjoys growing fungi and swabbing salamanders and is fascinated by the huge impact that microbes can have on living organisms and the world. She plans to continue her work in microbial ecology through the rest of her time at Fordham and into graduate school.