Fruit flies a sound idea for expert

Kyodo

For Azusa Kamikouchi, a celebrated university professor who specializes in the auditory and brain mechanisms of flies, the common fruit fly can teach us a lot about the human brain.

Kamikouchi, 38, leads a team at Nagoya University that is researching fruit flies, or Drosophila melanogaster, to learn how sound signals are transmitted to their brains.

“Fruit flies are handy to study as they have been researched for more than a century and there is a lot of accumulated information about them,” Kamikouchi said in one of the university’s laboratories, surrounded by more than 2,000 test tubes, each containing some 100 fruit flies around 2 to 3 mm in size.

The fruit fly is an ideal organism for research purposes due to its simple nervous system, Kamikouchi said. Its brain is small, with only 50,000 neurons on one side — compared to around 90 billion in the human brain.

“The flies seem to use their brains even when they court,” she said, adding her ultimate goal is to fully grasp their brain mechanism.

Kamikouchi is known for discovering that fruit flies sense sound and gravity via hearing organs at the bases of their antennae, and that this information is then transmitted to the brain through different neural pathways.

Kamikouchi used the green fluorescence protein discovered by Nobel chemistry laureate Osamu Shimomura, 84, to make the fly’s neurons glow, allowing her to trace the transmission process.

Because humans also sense gravity and sound through auditory organs, “it was a surprise to discover that the fruit fly has a similar system to human beings, although the two species have taken separate evolutionary paths for over 600 million years,” she said.

A lover of music and animals since childhood, Kamikouchi has always been intrigued by how sounds evoke certain responses in the brain and why different people enjoy different types of music.

To understand this correlation, she studied honeybees as a student at the University of Tokyo’s Graduate School of Pharmaceutical Sciences. After earning her doctorate in 2002, she changed her focus to flies and discovered that they communicate via sound.

While working as a research fellow at the university, she was invited to conduct joint research on the issue by a German academic she met at an international conference in Chicago. Kamikouchi moved to the University of Cologne in 2005 and worked there for three years.

After returning to Japan in 2008, she was appointed assistant professor at Tokyo University of Pharmacy and Life Sciences. She took up her current post at Nagoya University in 2011.

Kamikouchi has won several awards for her research, including the Japan Neuroscience Society Young Investigator Award last year.

Her successful academic career, however, means she has led a flexible family life. Shortly before moving to Germany, she married one of her graduate school peers.

“We had to live separately after getting married, but living in a different culture helped widen my perspectives,” she said.

After returning home, she gave birth to a daughter in 2010 but again had to live separately from her husband, a researcher in Tokyo, to take up her post at Nagoya University the following year. Her spouse travels to Nagoya on weekends to spend time with their daughter.

When Kamikouchi has to go overseas to attend a conference or conduct research, she asks her mother to take care of the child. The university also provides an ideal environment for researchers with children, having established a nursery and an after-school day care center on campus.

On weekdays, Kamikouchi wakes her daughter, 2, makes breakfast and has her picked up for the nursery before setting off for work.

After picking up her daughter in the evening and going home, she scans through research articles and writes papers of her own whenever she can find the time.

“Raising a child is challenging but enjoyable,” she said. “I try to do my best in both researching and child rearing.”

Since her professorial appointment, Kamikouchi has had to spend more and more time on lecturing and attending meetings. But she said she tries to make time so she can concentrate on her research.

Kamikouchi is currently instructing her 10-strong research team on techniques for dissecting flies, using equipment she made herself.

“Each day, I make new findings and realize that I am moving forward, although I’m not sure when I can reach my goal,” she said.