“I wasn’t expecting it, and I am so grateful” to receive the Natural Sciences and Engineering Research Council Alexander Graham Bell Canada Graduate Scholarship, which is awarded to the highest category of doctoral scholarship applicants and offers $35,000 annually for three years, Cherewyk said.
ergot is a fungusClaviceps purpurea) that reproduce during wet, rainy growing seasons and produce ergot or sclerotia bodies—black or dark purple kernels—that replace the natural grains of cereal crops such as rye, wheat, and barley. Sclerotia contains ergot alkaloids, which are toxic chemical compounds that have two different configurations – the S form (S-epimer) and the R form (R-epimer).
R-epimers are known to produce their toxic effect primarily through the mechanism of vasoconstriction, the narrowing of blood vessels, which slows or blocks blood flow.
Cherewyk’s research focuses on the mechanisms of S-epimer, which makes up about 30 percent of the alkaloid concentrations in infected grains. Historically, this epimer has not been closely studied or included in ergot standards because it was considered biologically inactive. She said that since R-epimers can transform into S-epimers and vice versa, it is important to measure both.
The permissible level of ergot alkaloids in animal feed and human diets is regulated due to its adverse effects, which can range from gangrene, lameness, and loss of cow tails. Over the centuries, human manifestations of ergot poisoning such as hallucinations, convulsions, and psychosis in those who ingested the affected pills have been associated with Salem witch trials and other persecutions.
“My research shows that S-epimer is toxic and can have adverse effects,” Cherewyk said. “I’m researching how these projectile eliminators cause toxic effects, and I’m studying ways to remove toxins from them for livestock and possibly humans.”
Results I published last year about the vasoconstrictor potential of S-epimer attracted the attention of major American scientific societies, which recognized it as an important advance in ergot research.
Global standards for ergot are based solely on R-epimer, and Cherewyk’s work will result in both epimers being included in the standards, said Dr. Barry Blakely (DVM, Ph.D.), professor at the Western College of Veterinary Medicine and the Center for Toxicology at USask.
Cherewyk’s work is unique for its analytical component that delves into how different concentrations of these alkaloids affect their effect, and how grain storage times and temperatures affect the concentration of these compounds.
It’s also started lab research on exposing ergot-contaminated grains to ammonia to study whether the process detoxifies the alkaloids — something researchers in zoology and other fields believe is an exciting idea, said Blakely, who is co-supervising Cherewyk’s doctoral work with WCVM associate professor. Dr. Ahmed Al-Disi (BVetSc, PhD).
“Farmers are already using ammonia to increase protein in lower-quality grains, so this is a very practical approach toward disease prevention and improving feed quality for animals,” he said.
Cherewyk is also studying whether exposing contaminated grains to ultraviolet light can detoxify ergot.
“So there are clinical, diagnostic, analytical, practical and theoretical components of her research that cover everything, and have implications for human health as well,” Blakely said.
“This research has a very local content that directly affects producers in Saskatchewan and has significant economic implications for this province and western Canada because it affects not only the livestock industry but grain exports,” he said.
Blakley said Cherewyk is another major contributor among the list of researchers who helped establish USask as a center for ergot research in Canada and earned it international respect in the field.
