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Keeping the Food We Eat Safer

UC chemist receives prestigious NSF CAREER grant to develop toxin-detecting biosensors.

Date: 1/14/2010 12:00:00 AM
By: Wendy Beckman
Phone: (513) 556-1826
Photos By: Dottie Stover, photojournalist

UC ingot   Suri Iyer, an assistant professor of chemistry in the McMicken College of Arts and Sciences received a grant from the National Science Foundation (NSF) for his research, “Tailored Glycoconjugates for the Precise Detection of Toxins and Pathogens.” The grant, an NSF CAREER award of $575,000, will allow Iyer to do fundamental research toward developing molecules that can function as biosensors to identify food-borne toxins released from Escherichia coli.
Suri Iyer has received an NSF CAREER Award given to young faculty.
Assistant Professor Suri Iyer guides graduate student Yun He (seated) and undergrad Tuan Dinh.

The long-term goal is to develop these molecular biosensors so they can serve as a tool for rapid detection of such food-borne toxins. Toxins produced by bacteria and other “bugs” are released by cells at the molecular level. Iyer’s group creates a type of carbohydrate called a glycoconjugate that they hope will eventually be used as a means of detecting the presence of the toxin. The carbohydrates “recognize” the toxins on a surface, react and cause something to change — like the color of a solution, which could be read by a measuring device, for example. In this way, the carbohydrates are called a “recognition molecule.”

Researchers working in Iyer’s lab make the molecules and then go to the lab of Alison Weiss, a professor of molecular genetics in UC’s College of Medicine, to test them. (Weiss is the principal investigator on a grant of her own to create the actual devices.)

One example of a toxin that the carbohydrates could recognize are the shiga toxins, such as E. coli. When ingested through improper food handling, the toxins released often cause severe gastric distress leading to kidney damage and even death.

Iyer's grant is for his research in developing molecular biosensors for rapid detection of food-borne toxins.
Iyer's grant is for his research in developing molecular biosensors for rapid detection of food-borne toxins.

“Children, elderly people and those who are immuno-compromised are often prescribed antibiotics to kill the bacteria,” says Iyer. “But this can cause a problem because the bacteria basically say, ‘OK, if I’m going to die, then I’m going to take everyone with me,’ and they release more toxin.’ The Centers for Disease Control and Prevention actually recommends not giving antibiotics in shiga outbreaks, because once complications begin occurring it’s too late. The sensors that we are working to develop would detect the toxins.”

Iyer hopes to apply this knowledge to many pathogens and pathways. For example, he and his team are working with a company in Dayton, UES, Inc., to develop a device that would be right on a package of meat to tell the consumer that it is safe to buy.

Some of the toxins that are dangerous to humans don’t affect animals at all, so Iyer and Weiss see applications all along the process.

Doctoral student Dan Lewallen attended the meeting of Nobel recipients in Lindau, Germany, in 2009.
PhD student Dan Lewallen is studying carbohydrates that could possibly detect swine flu.

“I’m involved in the biology at the packing plant testing the cattle as they go in before they’re slaughtered,” says Weiss, “For example, a recent outbreak involving spinach and lettuce was carried by cattle. The bacteria were in the streams, which feral pigs had drunk from and then trooped across fields, as feral pigs do, leaving deposits. Because of mechanized farming, the “little piggy gifts” get scooped up right along with everything else.”

“It makes sense to test as close to the source as possible,” Weiss continues. “It is highly unlikely that it will become contaminated downstream.”

While Iyer is sole investigator on the NSF grant, he is the co-investigator on Weiss’s National Institutes of Health grant. Weiss points out that when Iyer was being considered for the position at UC, he made contact with her to discuss her research. She says that their cross-college interdisciplinary research is “really very powerful.”

“People tend to get immersed in their only own discipline,” she says. “But Suri is actually a better biologist than I am a chemist! It’s a very productive collaboration.”

“Alison has been very instrumental in guiding me and my students in our research and has served as a mentor to me,” Iyer says. “I owe her a great deal of gratitude.”

Iyer has students from high school up through graduate students working in his lab.
Iyer, here with Ashish Kulkarni, says he has a 'United Nations' of students.

“I’m very proud of him,” says Weiss.

Iyer pays that mentorship forward by turning around and mentoring others. A secondary component to the NSF award is education. A small portion of the grant funds bring local high school students to Iyer’s lab to work in partnership with a UC undergraduate and graduate student. One of Iyer’s graduate students, Dan Lewallen, recently garnered some national attention by being chosen to attend the annual Lindau meeting of Nobel recipients for his work.

“I’ve really enjoyed working in Dr. Iyer’s lab,” says Lewallen. “He allows us to grow professionally — but not just on a scientific basis. He encourages us to experiment, to try out what we want to pursue. He’s the perfect PhD advisor, because as a doctoral student, I have to develop my own ideas.”

“Through this NSF CAREER award, we will bring under-represented and economically disadvantaged high-school students to a real science lab,” says Iyer. “I get them out of the fast food restaurant jobs to show them what real scientists do — what is possible for them to become. It’s not just about the money.”
Iyer stresses the importance of showing students from all walks of life, from all regions, what a real lab looks like.
Hailemichael Yosief is a second-year graduate student from Africa.

Iyer tries to stay in contact with all the young students after they leave his lab.

“They are either still in high school or have gone on to some of the top colleges, such as UC, Princeton, San Diego/Scripps and Urbana-Champaign,” says Iyer. “This is a good thing — helping a lot of people and creating impact.”

"I would recommend Suri as one of the best mentors in the department,” adds Lewallen.

Besides continuing a tradition of mentorship, Iyer also continues another long-held tradition in the Department of Chemistry in McMicken College.

Every assistant professor since 1998 has received an NSF CAREER grant,” says Iyer. “I’m happy to continue that tradition.”
Yun He, second-year graduate student, with Hailemichael Yosief in the background.
Someday Yun He may continue one or both of the examples that Iyer has set for her: mentoring and the NSF.

Related News:

UC Student’s Virus Research Finds Nobel Audience
Chemistry student Dan Lewallen attends the 59th Meeting of Nobel Laureates in Lindau, Germany, June 28 – July 3. What’s even more timely is Lewallen’s research.

Suri Iyer’s research is funded through National Science Foundation CAREER Award #0845005. This award was funded under the American Recovery and Reinvestment Act (ARRA) of 2009.