"Ichi-go, ichi-e." In English, the Japanese phrase roughly translates to "a once in a lifetime chance." This past summer, the U of A’s BRAVO! Program gave me a once in a lifetime chance: to meet new people, explore a foreign country, experience a new culture, and collaborate with researchers on the other side of the world. Funded by an NIH grant through the Biomedical Research Abroad: Vistas Open! Program (BRAVO!), a fellow student, Brianna Rico, and I traveled to Tokyo Metropolitan University located in Hachioji, Tokyo, Japan to research the distribution of polyphenols in sawtoothed oak leaves (Quercus acutissima) through a research connection with colleagues of our UBRP mentor, Dr. John Koprowski, Professor of Wildlife Conservation & Management.
We work with Dr. Noriko Tamura and her research group at the Tama Science Forest Garden, an experimental forest on Mt. Takao. They noticed that in certain tree species like the sawtooth oak (Quercus acutissima), the Japanese giant flying squirrel (Petaurista leucogenys) selected for only certain sections of a leaf, leaving feeding remains that appeared as if a quarter sized hole was punched out of the center of every leaf. Dr. Tamura, along with Dr. Fumio Hayashi from the Animal Ecology laboratory of the Tokyo Metropolitan University, hypothesized that the giant flying squirrels were selecting for low polyphenol concentrations in certain sections of the leaves.
Polyphenols are a family of compounds characterized by their numerous phenol groups. Ubiquitous in plants, these compounds contribute to plant properties such as color, resilience, and defense. One group of polyphenols in particular, tannins, act as a defense mechanism against predation by causing a bitter taste and precipitating digestive proteins, resulting in digestive complications in many mammals, including humans. Doctors Hayashi and Tamura believe that the giant flying squirrels were avoiding the peripheral portions of the leaves because of the adverse side effects caused by phenols.
Our research involved a combination of field work and lab work. Every Monday, we collected eaten and whole leaves from the Tama Science Forest Garden as well as other field sites around Mt. Takao. Field sites ranged from a park to a narrow trail above a steep precipice. The rest of the week, we brought the leaves back to the lab at Tokyo Metropolitan University to perform extraction and analysis of polyphenols.
The combination of field work and lab work proved to be doubly challenging. For example, we rarely observed any squirrels feeding: not only are the flying squirrels nocturnal, the trees were over 30 feet high. In lab, we also had to consider another factor: time. We had to determine if the polyphenols in our leaves degraded over time, and whether transportation and storage time would affect our experiment. Despite these difficulties, we managed to collect preliminary results that showed a higher polyphenol concentration in the peripheral sections of the Quercus acutissima leaves.
Many plant chemistry research use insects as a model because of their precision in their selection of chemicals. We rarely find mammals that exhibit such precise feeding selection, selecting even within sections of a leaf. Observing the giant flying squirrels and learning about their chemical selection allows us to understand mammals, like ourselves, better. Future research will involve identification of individual polyphenols by High Performance Liquid Chromatography and their role in giant flying squirrel physiology. We hope to identify the phenols that contribute directly to this feeding behavior. Additionally, the tree species of this study, Quercus acutissima, have been used in traditional Asian medicine as an antidiuretic. Identifying polyphenols in the leaves of this species may also have some future human health implications.
My time in Japan was not completely spent on research. On the weekends, we took advantage of the expansive train and subway system and toured Japan. In Yokohama, Tokyo, we visited the Pokémon Center. In Akihabara, we ate in our first maid café. In Harajuku, we saw many street fashions as well as cosplay. The highlight of our summer was conquering Mt. Fuji and watching the clouds part to reveal a beautiful sunrise at the peak. Afterwards, we soaked our sore muscles in a hot spring at the base of the mountain and slept the entire bus ride back.
When I look back on my research in Japan, I realize that I was able to partake in a wonderful, unique experience. In addition to learning about the feeding behaviors of the Japanese giant flying squirrel, I discovered that international collaboration is amazing. There was much for me to learn and much for me to share with the researchers at Tokyo Metropolitan University. The students enjoyed our stories on Arizona wildlife like scorpions, horned lizards, and tortoises, which are not seen in Japan. On the other hand, I was able to see wildlife that I have never seen back in Arizona, such as the red face of the Japanese raccoon dog, Japanese mountain leeches preying on a giant earthworm, and great blobs of frog eggs in sticky, white sacks hanging from trees.
In addition, every Tuesday, we met in the Animal Ecology laboratory to share research progress, to socialize, and to eat and drink. These weekly gatherings became our refuge in an unfamiliar country - we asked questions about the customs we did not understand and ate cake together. They asked us about life in the States, like how big the streets were and what happened after you are stung by a scorpion. Communication was not generally an issue, but if all else failed whiteboard Pictionary always helped clear things up.
Even though we spoke a different language, our mutual fascination with science helped us understand each other. And of course, happy hour is universal.