SCHOOL OF ENGINEERING, TOHOKU UNIVERSITY Driving Force THE POWER TO MAKE TOMORROW INTERVIIEW REPORT
SCHOOL OF ENGINEERING, TOHOKU UNIVERSITY Driving Force THE POWER TO MAKE TOMORROW INTERVIIEW REPORT

Pursue what you think is interesting right then and there, beyond which lies a vision of your future Pursue what you think is interesting right then and there, beyond which lies a vision of your future

Associate Professor
Department of Applied Physics
Graduate School of Engineering, Tohoku University
Shuichi Nakamura

© School of Engineering, Tohoku University

Bacteria move by using their flagellar motors
How does this actually work?

Bacteria are simple, single-celled organisms, but surprisingly, they are equipped with motors that help them move toward a goal and sensors that capture information from the outside world. “Bacteria move in very viscous, sticky environments. It's like us humans swimming in a pool of honey. To be able to move about in such a difficult environment, bacteria rotate their tail-like flagella,” says Associate Professor Shuichi Nakamura, whose main research at the Department of Applied Physics at the Graduate School of Engineering, Tohoku University, includes bacterial motion. He says his interest in this topic was piqued by a single electron microscope photo he saw when he was a student at the College of Agriculture of Ibaraki University. He explains, “That photo was shocking. Spirochetes (which are spiral-shaped bacteria) could be seen puncturing the surface on all the folds of a large intestine. Spirochetes can't puncture anything unless they move in some way. Although it was known that bacteria moved by using their flagellar motors and that hydrogen ions were their energy source, the mechanisms that made these work had not yet been made clear. That's what I wanted to find out, and this strong urge made me step into this field.”

After graduating from the College of Agriculture of Ibaraki University, Associate Professor Nakamura continued his studies at the Graduate School of Agriculture of the same University, enrolling in the master's curriculum of the Faculty of Agricultural Studies. While attending graduate school, he deepened his research into bacterial motion at the National Food Research Institute (currently the Food Research Institute at the National Agriculture and Food Research Organization or NARO). He says, “At the time, there was a researcher from the private sector at the National Food Research Institute who specialized in bacterial motion research. Under that person's guidance, I conducted research on how spirochetes taken from pigs move in a viscous environment. Interestingly, the more viscous the environment, the faster spirochetes move.”

Toward a new field of biophysics which uses physics as a tool
to understand the structure and functions of organisms

　

For Associate Professor Nakamura, the two years he devoted to research at the National Food Research Institute was also a time for encountering new perspectives. He explains, “Up until then, I was in the fields of agriculture and biology where I observed phenomena, compared various things and considered them. On the other hand, the study of motion is originally a physics subject where we try to measure, analyze and quantify even the most complex phenomena in a simple way. The two years I spent at the Institute taught me the fun of looking at things from a physics perspective, and paved the way to a new field of biophysics which uses physics as a tool to understand the structure and functions of organisms.

After receiving his master's degree, he enrolled at Osaka University's Graduate School of Frontier Biosciences. From the world of agriculture to the world of science. According to him, there were strategic overtones to this change in track. He says, “For four years I learned from biological and veterinary perspectives at the College of Agriculture, while for two years I tried to acquire a physics point of view at the National Food Research Institute. When I thought about what I should do next, I knew that my basic knowledge of motion was still shaky, so I thought I should learn more about flagella and motion itself.”

During the three years of his doctoral degree, he conducted research under various conditions in order to examine the functions of a flagellar motor. His research was done by accumulating the results of various experiments that examined the factors that slowed the motor down and the effects of changes in the gene on the speed and power of its movement. His research then gradually revealed the mechanisms of a flagellar motor's rotation and the factors that were important for its rotation. He says, “One of the fruits of these studies was deepening our knowledge of molecular biology that manipulates genes.”

東北大学 工学研究科・工学部 Driving Force 明日を創るチカラ INTERVIIEW REPORT

Broadening the scope of research,
maintaining emphasis on learning from living things

When biophysicists want to look at something under a microscope, it is common practice for them to create their own systems, and Associate Professor Nakamura says that that made it easier for him to adapt to the world of engineering. He took up a new post at Tohoku University in 2010. Becoming a researcher at the Graduate School of Engineering further broadened his research. While continuing his research on flagellar motors from the perspective of physical science, he has also been researching themes that are connected to medicine and veterinary science such as their relationship with virulence. Moreover, he is also conducting research in an engineering field called micromachinery. He says, “I feel that my strength is that I can become an agricultural researcher, a physicist, and an engineering researcher depending on where I am. When I conduct collaborative research, agricultural researchers seek my physics perspective, while engineers ask about my agricultural and biology background. I find it fulfilling to be able to provide perspectives that they don't have in their field.”

His latest research results revealed how a type of spirochete, Leptospira (bacteria that causes leptospirosis, a zoonotic disease often found in tropical and subtropical regions), infects and destroys organs. The application of these results to the development of new preventative measures and treatment is promising. He is also focusing on the light sensors that bacteria have. He is conducting research on the mechanisms and functions of bacterial motion that is activated when bacteria are exposed to light. He says, “Through even more precise measurements, I want to clarify the rotation mechanism of a flagellar motor and why hydrogen ions are converted into rotation. I hope this research will become the foundation for the development of nanomachines and other machinery that operate on a microscopic level. What's important is the approach of learning from living things.”

Always asking why leads to better research

The common perception that people have about engineering is that it is about making things. Before taking up a post at Tohoku University, Associate Professor Nakamura also thought that way. He says, “When I joined the Graduate School of Engineering, I was surprised at how much emphasis was given on the basics. They also emphasize the importance of always asking why. This emphasis is the key to make our research even better. I also feel that the researchers here also emphasize the value of getting the results of their research out into the world and of being useful to society.

Associate Professor Nakamura, whose favorite book as a child was the series of books on animals by Ernest Thompson Seton, and whose childhood dream was to become a zookeeper, says that the Aobayama Campus is also a great environment for raising kids. “My children and I collect praying mantises and grasshoppers in Aobayama and we keep them in insect cages at home. After observing them, we release them where we took them from because of ecological concerns, but it's quite challenging,” he laughs.

In the end, he has this advice to give to high school students who are about to make decisions on their career paths. He says, “My love for living things, especially animals, is what brought me this far. If you are unsure about your career path, think about what you like, even if you only like it a little bit. You may find something for you if you proceed from there. When you're in high school, sometimes there is a pressure to be like everybody else. But if you can be honest with your heart about what you like and want to do, you may find something new about yourself.”