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Frogs were Mysteriously Dying Across the Globe: Joyce Longcore Cracked the Case

Joyce Longcore. Courtesy of the University of Maine

Joyce Longcore’s unorthodox career as a mycologist peaked in a stunning burst of achievement in 1997, which later resulted in a Golden Goose Award. Longcore, Associate Research Professor at the University of Maine in Orono, nailed the mysterious organism that was decimating frog populations all over the world as a chytrid, an obscure aquatic fungus, and devised a way to isolate it into pure culture so it could be studied by other researchers.

Two veterinary scientists at the Smithsonian National Zoo, Don Nichols and Allan Pessier, found Longcore while trying to figure out what was killing the zoo's blue poison dart frogs. They saw her ultrastructural photos of chytrids on a website of zoosporic fungus that University of Maine mycologist Mel Fuller maintained. So they sent images of the organism they were dealing with.

“I could tell by looking at it it was a chytrid,” Longcore said.

The Smithsonian scientists soon sent her fresh samples of infected frog skin. Longcore was a dab hand at isolating chytrids, her specialty, into pure culture. This strange new type took a couple of tries, but on her birthday, over the long Columbus Day weekend, Longcore went into the lab and saw that the liquid medium she had put the culture in had turned opalescent: something was growing there. Under the microscope, she could see it was a fungus. She had found a way to get the chytrid to proliferate.

“That meant we could do research on the organism,” she said.

Those were heady days, Longcore recalled, as research teams around the world raced to match the newly named Batrachochytrium dendrobatidis (Bd) with their own local die-offs. Ever since her groundbreaking discovery, Longcore has been included in research teams and invited to teach isolation techniques and participate in conferences. When the grant money was flowing (and only then, because she wasn't salaried), she even got paid.

Bd is the big thing publicly, and it was a lot of fun, getting frogs in the mail every day, but I liked the systematics of the group”— mycologists, that is, other scientists who love the strange creatures of this discrete kingdom of living things — “figuring out the amazing diversity.”

Longcore grew up in rural southwestern Michigan. She was an impressive mycologist even in her undergraduate days at the University of Michigan at Ann Arbor, and she spent an additional year there after graduation working for Frederick Sparrow, a leading authority on aquatic fungi.

She got her master’s degree from Indiana University, and then married Jerry Longcore, who worked as a field biologist with the United States Fish and Wildlife Service and, later, the U.S. Geological Survey. After the birth of their first child in 1967, Joyce didn’t work in the lab for 18 years. For much of that time, the family lived in Orono.

“I kept house. We gardened in the summer. Jerry was gone a lot and I ran the place,” Longcore recalled. “I didn't pine for this science business, though. I couldn’t flirt around the edges. I had to have a project.”

When her older son went to college, Longcore considered getting a part-time job in a grocery store. Then Joan Brooks came calling with that aforementioned project. Brooks, a biologist at Orono who later developed a peat-based sewage filtration system, needed a mycologist for a study of aquatic systems. Another Orono professor remembered Longcore from college at Ann Arbor and recommended her.

“Once I got back behind the microscope, I thought, 'Oh, yes, this is what I do,'” Longcore recalled. Her most valued tool still is the light microscope she got in order to work with Brooks in the 1980s.

When that project ended, Longcore went back for her Ph.D. at the University of Maine. The logical progression then was to get a grant and do research, but “I didn't get a grant,” she said. However, with space in a colleague’s lab and her trusty microscope, Longcore did her own research and published it.

“I haven't been paid for years and years, but my department has been very supportive,” said Longcore, who is presently in the process of moving her frozen chytrid collection to the University of Michigan, and “trying to plan ahead a little bit” as she approaches her 80th birthday.

Chytridiomycota, the chytrid group, are ancient, water-loving fungi; even types that live in soil need free-running water to disperse their motile spores, equipped with flagella to help them swim. Bd's parasitism is a departure from the chytrids’ usual habits (though a different chytrid also preys on salamanders).

Amphibians rely on their skin for breathing. The disease Bd causes, Chytridiomycosis, thickens frogs’ and toads’ skin to the point where that function ceases. The disease has mortality rates that approach 100 percent in some populations. Bd appears to have arisen only within the past century on the Korean peninsula, and dispersed around the world in just a few decades.

Advances in technology and genomics make it possible now to see the differences among various fungi at the cellular level. When Longcore was starting out, morphology was the chief method for categorizing them.

Scientists are only beginning to understand the role fungi play in biology, she said. Fungi may help trees to talk to one another in a field, for example. Orchid seeds depend on fungus to get started. Some fungi work in decomposition, clearing away detritus; we use some, like mushrooms, as food; still others are parasites.

Asked if fungi are important, Longcore said, “Oh my goodness, yes! Fungi hold the world together.”

Representative Image Caption
<p>Joyce Longcore. Courtesy of the University of Maine</p>
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