By Dale Denwalt
Copyright 2020, The Oklahoman
The evolutionary defenses of a fungus could help humans deal with another defense mechanism, the noxious odor of skunk spray.
Robert H. Cichewicz and his Natural Products Discovery Group were hunting for a chemical to help treat breast cancer when they found a surprising molecule made by a fungus collected thousands of miles away.
The molecule dubbed “pericosine” bonds with the odorous compounds sprayed by skunks and neutralizes the smell, Cichewicz said. Pericosine is produced inside a fungus found in an Alaskan soil sample given to his lab at the University of Oklahoma.
Instead of using the chemical to fight off other fungi competing for the same food source, pericosine apparently helps deactivate toxins in its environment, a unique defense from organisms that don’t move around much.
“We were asking the question then, ‘what could you do with this,'” Cichewicz said. “In terms of looking at the broad spectrum of things that people find noxious in their environment, we ended up going with one that was a pretty big signature.”
It deactivates skunk odor in seconds and is water-soluble, meaning it easily washes out with water, he said.
A commercial use
The university holds a patent for the chemical’s use in neutralizing irritants. It’s licensed to Azorilla, a portfolio company of Oklahoma City-based Ascend BioVentures.
Azorilla is developing the chemical for commercial use and for the past few months has been searching for inexpensive ways of production. Cichewicz is Azorilla’s chief science officer; its chief executive is Ascend BioVentures CEO Elaine Hamm.
“We’re looking at a number of different large companies that have actually reached out to Robert,” Hamm said. “Not just from the animal health world and people that are interested in solving the the skunk smell, but other large chemical companies that want to look at the potential of (pericosine) being a general odor neutralizer.”
It can be made naturally by allowing the fungus to produce the molecule, or by using chemistry to make a synthetic product. Hamm said one of the challenges is finding a way to make it on a large scale, large enough to meet the demands of companies willing to bring it to market.
About the fungus
Cichewicz runs a citizen-science project at OU that accepts samples from the general public. Landowners in the United States send soil from their backyards to the Natural Products Discovery Group at OU.
The sample where Cichewicz found the odor-killing compound came from Alaska. In that soil, he found a type of Tolypocladium fungus.
To grow some of the fungus specimens, he uses what might be an odd food source in a scientific setting: Cheerios.
“We go straight to regular Cheerios, not the fancy flavors or anything,” Cichewicz said.
Not the generic kind, either, because they don’t hold up as well in the extreme heat of sterilization.
“They will crumble. But the real Cheerios, they shrink and then we add water and rehydrate them,” he said. “If you use the generic ones, all you get is one flat kind-of schmear of Cheerio-like substance.”
The torus, or doughnut-shaped cereal has more surface area for the fungi to thrive, he added.
Cichewicz urged people to keep looking for and appreciating what nature has to offer.
“That’s really the bottom line here, is that we take so much of the natural world for granted. Yet right there under your feet, the soil that you’re standing on, walking on, tromping on, discarding to the side, that thing’s rich with life,” he said. “If you’re willing to take a look and try to figure out what the fungi are doing, then yeah, I think there’s a lot of rewards to be had in there.”
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