CHAMPAIGN, Ill., 1/17/18: Far beneath the hulls of sailing ships on the Great Lakes are sediment habitats active with what may one day prove to be a priceless treasure. University of Illinois scientists hope that freshwater fungi inventoried in a new study might potentially contribute to a future treatment for childhood cancer.
Molds, spores, mushrooms, and other types of fungi have been studied in various land environments and used for the bioactive compounds they produce to combat human diseases. To date, however, few studies have explored the fungal diversity that Lakes Michigan and Superior have to offer. Fewer than 20 fungal species had been found in Lake Michigan.
“Freshwater lakes have distinctive habitats and serve as a largely untapped resource for discovering unique fungi,” said Illinois Natural History Survey (INHS) mycologist Andrew Miller.
A recently completed INHS study is the first comprehensive and systematic inventory of fungi from Great Lakes sediments. Researchers collected 145 sediment samples from as much as 900 feet below the surface of Lake Michigan in the summers of 2014, 2015, and 2016, and 20 samples from Lake Superior.
The researchers targeted habitats at the very bottom of the lakes that they assumed would contain only fungal spores that washed in from terrestrial habitats surrounding the lakes. However, they found a highly diverse, undiscovered community of actively growing aquatic fungi.
The researchers combined the traditional fungi sampling method of growing cultures in the laboratory with the newer techniques of sequencing DNA from the environment. Identifying and categorizing fungal organisms can be challenging because some of those sampled are very tiny, one-celled organisms, which are very difficult to grow in cultures.
“It’s not Loch Ness fungi that we’re dealing with,” Miller said. “We know they are out there. We’re just not able to get them to grow in the lab to examine them.”
Using both techniques, they found 465 species of fungi, only two of which have been found in previous studies. They tried to match what they found with scientific databases of known organisms.
“The fact that as much as 75 percent of the species couldn’t be identified to anything in the fungal databases indicates that these are mostly novel or new species that we don’t know about,” Miller said.
The study was part of a National Institutes of Health initiative to look for natural biological products found in the United States, particularly compounds that show the promise of curing childhood cancers. Miller is part of a collaborative team with the Natural Products Discovery Group at the University of Oklahoma (http://npdg.ou.edu/research), where all of his cultures are sent for chemistry testing. Miller says that eventually some of his study samples will be sent to the National Cancer Institute for further research.
Although it will take years of testing to determine if any of the newly found fungi have beneficial biological properties, the study shows that the Great Lakes are an underexplored potential source of fungi that the world may have never seen, Miller said.
This study was published in the Journal of Great Lakes Research.
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