Bulletin of Keio University Faculty of Science and Technology
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09 Kiyotake Suenaga I owe what I am today to my respected teacher

Discovering one unknown substance after another from marine cyanobacteria, Dr. Suenaga endeavors to approach and elucidate the usefulness of such substances. He has inherited his preparedness both as a researcher and educator to his respected teacher whom he encountered as a university student. Once a young student lacking an interest in chemistry, why and how did he become bent on the exploration of unknown substances?


1 An encounter with a great teacher

How did you spend your childhood?
      I wm school. Also, I was never told by my parents to study hard. So until I graduated from junior high school, I had rarely studied at home.
      As a small boy, I thought to myself that I would find employment with the Japan National Railways (now JR) in the future. For me this seemed to be a natural course of life since three generations of my family, from my grand-grandfather to my immediate father, had worked for the National Railways. So I was raised in official National Railways housing. The fact is, my father was one of the first-generation drivers of the Tohoku Shinkansen SuperExpress. When I was an elementary school boy, my father was studying hard to become a Shinkansen driver to prepare for the Tohoku Shinkansen line opening, which I still remember. My own son appears to respect his grandfather much more than his father (myself) because he has no idea about what I’m doing.

What was the impetus for you to make a decision to specialize in chemistry?
      I was once reaching for the universe. In fact, my interest had been in physics rather than chemistry until I became a university student. But by the time it was time for me to choose a lab to study in, my interest had shifted to natural products and other complex substances. At Nagoya University in those days, however, studying in the organic chemistry group of the Graduate School of Chemistry required a kind of resolution. It was because there were two professors’ labs available – Prof. Ryoji Noyori who was later to win a Nobel Prize, and Prof. Kiyoyuki Yamada, my teacher, both famous for being very strict. I finally decided to join Prof. Yamada’s lab.

photoWhat was the atmosphere of your lab?
      As a newcomer, I had no idea of what the Yamada lab was like, but soon I found that the lab was with great traditions. Dr. Yoshimasa Hirata, the predecessor and teacher of Dr. Yamada, is famous worldwide for his research on tetrodotoxin (globefish poison). Furthermore, Dr. Osamu Shimomura, awarded the 2008 Nobel Prize in Chemistry for his research into green fluorescent protein found in jellyfish, had once studied in Dr. Hirata’s lab. By chance, I put myself in an environment that is one of the greatest centers of natural product chemistry.
      Even today, I make it a rule to introduce my respected teacher Dr. Yamada’s research work “Carcinogenic Substance of Bracken” at the beginning of the “Chemistry of biologically active molecules” class work for juniors of the Department of Chemistry. Bracken was known to cause livestock poisoning and study of this problem had been undertaken since the 19th century mainly in Europe. In this process, it came to be known that bracken has carcinogenic property, which drove many researchers around the world into competing with each other to identify the culprit. However, the carcinogenic substance could hardly be captured because it is very unstable and sensitive and because a simple biological test method as a guide for extraction and separation could not be established for years. Finally Dr. Yamada identified the substance by inventing a moderate extraction separation method after conducting carcinogenic tests untiringly – a process that took many years and required a large quantity of extraction samples.
      Apart from being my teacher’s achievement, this study is a wonderful research work that is sure to find a place in history. In this connection, let me add one point: his work also made it clear that bracken can be eaten safely if it is cooked because the carcinogenic substance is completely decomposed when cooked.



1 An encounter with a great teacher
2 Starting a researcher’s life
3 Putting much importance on time
for communicating with family 
and students
Profile Kiyotake Suenaga Dr. Suenaga’s specialty is marine natural product chemistry. He is engaged in exploration of biologically active substances. Currently, his focus is on marine cyanobacteria. In 1992, he was enrolled in Nagoya University’s Graduate School of Science. In 1995, he left the doctor’s course to become a research assistant for the Department of Chemistry, Faculty of Science of the university. In 1997, he acquired a doctor’s degree (in science). After serving as a research assistant for Shizuoka Prefectural University (Pharmaceutical Department) then as an assistant professor for the University of Tsukuba (Department of Chemistry), in 2006 he assumed the current position as an associate professor for Department of Chemistry, Keio University Faculty of Science and Technology. Dr. Suenaga was honored with the Inoue Research Award for Young Scientists in 1998 and the Chemical Society of Japan Award for Young Chemists in 2003.

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