“Let’s Listen to the Talk of a Recipient of the Ig Nobel Prize! —Tracing a Secret of Onions that Doesn’t Cause Tears—” Program Conducted

February 24, 2014

On Friday, January 17, the extracurricular liberal arts program of the Student Center “Let’s Listen to the Talk of a Recipient of the Ig Nobel Prize!—Tracing a Secret of Onions that Doesn’t Cause Tears” was conducted on the Koganei campus.

Professor Toshiyuki Nagata, of the Faculty of Bioscience and Applied Chemistry, Hosei University, received the Ig Nobel Prize in Chemistry in September 2013. The prize was awarded for his discovery of an enzyme contained in onions that synthesizes a component that makes the eyes water. The program was planned based on the desire that we provide an opportunity to listen to his research contents and the award ceremony that he attended directly from Professor Nagata.

First, a pleasant atmosphere at the ceremony, held at Sanders Theatre at Harvard University, was introduced with photos, followed by Professor Nagata’s presentation about his research contents.

At the beginning, he introduced the origin of genus alliums, their features as vegetables, types of onions and the mechanism that causes them to grow plump. Regarding an enzyme contained in onions that synthesizes a component that makes the eyes water, the main topic of the program, he compared conventional synthesis with a new type synthesis, which was clarified by the discovery of the enzyme. In both mechanisms, PRENCSO, a major sulfur compound in onions, is acted upon by the enzyme alliinase to produce an unstable intermediate product – propenyl sulfenic acid. Following this, a lachrymatory factor (LF) has been so far presumed to be produced spontaneously. However, in his new theory, propenyl sulfenic acid, an unstable intermediate product, is acted upon by a previously undiscovered enzyme, lachrymatory-factor synthase (LFS) to synthesize the lachrymatory factor (LF).

He explained that LFS was produced in most genus alliums and that it was possible to develop non-lachrymatory onions, which contained more components beneficial to health, by suppressing the expression of LFS. Moreover, he indicated that LFS had the potential to be used as a test agent for dry eye syndrome in the future. However, although onions that do not cause tears are produced at this time, they have not come onto the market. Professor Nagata said that this was because onions that did not cause tears were genetically modified plants, which had been hit by rumors in Japan. Meanwhile, in association with this research, which was carried out jointly with a company, Professor Nagata introduced other research efforts that he has conducted with various companies. We all spent a very worthwhile time learning about his research projects.

<Reported by KYOPRO staff> Fumina Kitamura (first year, of the Department of Chemical Science and Technology, Faculty of Bioscience and Applied Chemistry)