[No. 141] Hiroyuki Kubota

I am currently a researcher at the Yakult Central Institute. When I first entered university, I had no clear goals for the future, and I decided on my path while discovering what I wanted to do during my university life. I'm not sure how helpful it will be, but I would like to share my experiences from my university days and my professional life.

In high school, I was terrible at Japanese language but liked physics and chemistry, so I chose to pursue the sciences. Following that path, I took the entrance exam for Category 3 at the Faculty of Science and Technology, Keio University. I chose Category 3 because it offered a broad entry point to the Department of Applied Chemistry. That said, I had no specific reason for wanting to join the Department of Applied Chemistry; I was simply drawn to the vague image of applying chemistry. As a result, when it came time to choose my department for my second year, I easily changed my mind and selected the Department of Biosciences and Informatics. This was because I had become more interested in life sciences, and also because the department had just been established, meaning I could be part of its first cohort, which I thought would motivate me to focus on my studies. It was mostly as I expected, but since I hadn't studied biology in high school, I lacked the foundational knowledge and struggled considerably to keep up with the lectures. Furthermore, the friends I made in the department were all brilliant, and for a while, I felt like I had wandered into a very challenging place. In the end, however, I was able to enjoy my undergraduate life, drawing great inspiration from my outstanding peers.

In the laboratory, I was supervised by Professor Tomonori Sato. My research theme was to search for peptides that bind to the receptors of the influenza virus, with the goal of preventing infection. Although I was taught by my senior colleagues, I felt a sense of reward and enjoyment I had never experienced before in conducting experiments on my own initiative. On the other hand, there were many times I felt discouraged when I couldn't get good results no matter how many times I tried. I was able to overcome these moments of near-despair thanks to my seniors, who supported me with appropriate advice and cheerful jokes, and my peers, who struggled and suffered alongside me while offering encouragement. I am truly grateful to them. I believe that my ability to continue loving research despite the hardships is what inspired me to pursue a research position during my job search later on. Outside of research, a fond memory is winning the inter-laboratory softball tournament when I was a first-year master's student. The main reason for our victory was that we had many experienced players, including a senior who had been on the baseball team. However, even amateur members like me were rigorously trained by him during morning practices, so perhaps I contributed a little. The year after that senior graduated, I took over as team captain, but we were quickly eliminated (laughs). In addition, our annual laboratory summer retreat always turned into a sports camp, and of course, we enjoyed banquets at night. In this way, I spent a fulfilling laboratory life, both academically and recreationally.

Driven by my love for experiments and a desire to do work related to human health, I pursued a research position and joined Yakult Honsha. After joining the company, I was assigned to a laboratory conducting basic research at the Central Institute. However, my knowledge of microorganisms was virtually nil, and I had only ever handled *E. coli* in experiments, so I had to start from scratch. There, I learned that a wide variety of bacteria have established a mutualistic relationship (a symbiosis in which both humans and bacteria benefit) in the human gut, and that there are many unknown bacteria that cannot be cultured. I was drawn into the depth and fascination of intestinal microbiota research. Three years later, I was fortunate enough to be offered a position at our company's research institute in Ghent, in the Kingdom of Belgium. As I had been studying English with the goal of working abroad, I decided to seize the opportunity and take on the challenge. I spent four years there, engaged in research on the intestinal microbiota of Europeans. Research life in a different culture was a series of discoveries, which also led to discoveries about myself. For example, and this may be typical of Japanese people, I found it difficult to state my opinions clearly, my presentations were monotonous and lacked intonation, and I couldn't pronounce the English L and R sounds correctly. Just because I became aware of these things didn't mean I could easily improve them, but recognizing my weaknesses and being mentally prepared was a major plus. I also noticed a difference in the approach to work; the researchers in Belgium were better at switching between "on" and "off" modes and valued their personal time. Regarding this point, although I am now back in Japan continuing my research, I am able to approach my work with more focus and take all of my paid leave. It seems I've thoroughly absorbed the convenient parts (laughs). It has been about 10 years since I joined the company, and I still find research enjoyable and spend my days constantly learning.

Looking back, I realize that I have primarily made decisions about my path based on what I "like" or "dislike." I was fortunate to find something I loved during my university life and to be able to make a career out of it, and I believe Keio University provided the environment that made this possible. For those like me who do not have clear future goals, I encourage you to try various things during your university life and find what you love and what you want to do.