- Author: Kathy Keatley Garvey
By Bruce D. Hammock, professor of entomology, UC Davis Department of Entomology
S. George Kamita, researcher, Hammock lab, UC Davis Department of Entomology
Susumu Maeda died unexpectedly of natural causes in his sleep on March 26, 1998, in Tokyo, Japan. At the time of his death, he appeared to be in perfect health and was enjoying the fruits of his labors to establish large research laboratories both in the United States and in his native Japan.
Susumu was born on April 9, 1950, the second son of Dr. and Mrs. Tsuneo Maeda of Matsumoto, Japan. He spent his youth in the Japanese Alps where he developed a lifelong love of mountain climbing and hiking as well as a deep interest in the natural history of insects. In his youth Susumu also studied the violin under the tutelage of Shinichi Suzuki and developed an intense love of classical music. His given name Susumu means 'to advance or progress.' Following his death he was given the Buddhist name Kenshininshakujyoshin which roughly means 'sincere seeker of knowledge' as a tribute to his lifelong commitment to science. Susumu is survived by his wife Hiroko of Davis and his parents.
Susumu graduated from Matsumoto-Fukashi Senior High School and was accepted to the University of Tokyo where he received his B.S. (1975), M.S. (1978, and Ph.D. (1983). His graduate research in the H. Watanabe laboratory focused on the densonucleosis virus of the silkworm Bombyx mori. In 1978 he accepted a position at Tottori University as an Assistant Professor. He spent one year studying with Yoshinori Tanada at the University of California, Berkeley in 1980 where he met Hiroko Murai who later became his wife. While in the U. S., Susumu also studied in the James and Ellen Strauss laboratories at the California Institute of Technology. Susumu actively taught at Tottori University until 1998 while at the same time commuting to Tokyo for research and internationally as a consultant on transgenic expression for companies involved in pharmaceutical and agricultural research. In 1987 he joined the Zoecon Corporation in Palo Alto, California, where he first expressed and insect neurohormone using a baculovirus and demonstrated that it disrupted insect development. In 1988 he joined the Department of Entomology at Davis, and in 1996 he accepted a concurrent position as Director of the Laboratory of Molecular Entomology and Baculovirology at the Institute of Physical and Chemical Research (RIKEN) in Wako, Japan. A research appointment at RIKEN is one of the highest honors for a scientist in Japan. With these two laboratories Susumu was poised to see his dreams come true.
The viral diseases of the silkworm, B. mori, first caught Susumu's interest early in his career and this proved a focus for all of his later work. He specialized in the baculovirus of B. mori but worked on several other viruses as well in addition to the basic biology of the silkworm. Production of recombinant proteins like human interferon, development of viral insecticides, basic investigations of apoptosis, fundamental developmental biology, host range, genomics and other projects all emanated from his original theme.
Susumu probably is best known for his development of the B. mori expression system reported in 1985 in the journal Nature. This system is analogous to the similar system developed by Max Summers and Associates at Texas A&M University, but it uses as host the domesticated silkworm, an animal that has been in culture for thousands of years. This expression system opened the door to the inexpensive production of recombinant proteins in mass reared whole insects. This system thus had a great impact on the production of recombinant drugs especially in developing countries. Fundamental science also has benefited greatly from the use of this eucaryotic expression system. An application of the in vivo expression system was realized with the development of the first recombinant viral insecticides. Susumu's laboratory demonstrated the concept that these natural biological control agents could be modified to make them more useful in field and row crop agriculture using B mori and then moved on to develop viruses for the control of the most serious crop pests worldwide. He was involved in the first effort to modify these viruses by expression of neurohormones, insect enzymes and peptide toxins, and before his death the recombinant viruses resulting from his pioneering efforts were in field trial on three continents.
Many aspects of Susumu's research showed tremendous foresight and have an ever-expanding impact on science. However, one of his most noteworthy accomplishments was the total sequencing of the genome of a large DNA virus, the baculovirus of B. mori. Susumu initiated this work in earnest as soon as he arrived at Davis. At the time such an effort was criticized by many as a mindless goal. However, this virus was one of the first organisms to be totally sequenced, and helped usher in the concept of using high throughput sequencing to generate genomic databases. The now common human, crop, pest and other genomic projects attest to Susumu's farsighted approach. At RIKEN he was positioned to undertake a massive project to sequence the entire genome of the silkworm as a model system to study fundamental biology as well as agricultural pest insects. Susumu made extensive use of hypothesis driven science, but he also worked strategically. His project to sequence the genome of the baculovirus of B. mori was expected to lead to a molecular-level understanding of how viruses alter the behavior of their host and the complex biochemical interactions, which determine host range of viruses. Susumu also laid the groundwork through his sequencing projects to address some of the most fundamental questions in modern biology including apoptosis and recognition of self and nonself. It is sad to many of us that the full exploitation of this sequence must fall to others. Thus, a retrospective of Susumu's science illustrates a man who pioneered a technology that positively impacted both medicine and agriculture and also proved a valuable tool in elucidating basic life processes.
Susumu was active in many professional organizations including the American Society for Virology, Society for Invertebrate Pathology, Entomological Society of America, American Society for Microbiology and American Society for Biochemistry and Molecular Biology. Susumu was honored by his colleagues with many awards, but possibly his most cherished occurred when Susumu and Hiroko had an audience with Emperor Akihito of Japan to discuss his research. He was recognized as a rising star of molecular virology in Japan. In both his laboratories in the U.S. and Japan, Susumu utilized advanced techniques in molecular biology to elucidate the intricacies of the interaction of insect viruses with their hosts. During the years that Susumu was a professor at Davis, he trained over 50 scientists who took his teaching throughout the world. His associates are now in Australia, China, Egypt, Japan, India, Israel, Korea, Russia, Taiwan, and other countries. He was known among his students as a hard working and enthusiastic scientist who brought inspiration as well as joy to his laboratory. Susumu was a conscientious faculty member, seldom missing a faculty or committee meeting and he worked hard to make Davis a still better intellectual community. The loss of such a vigorous, dynamic and caring scientist had a major impact on his colleagues around the world.
A mulberry tree planted in Susumu's honor recalls his first months in Davis when leaves from mulberry trees around the city vanished in the wee hours of the morning to feed his voracious silkworm colonies. In March of 1999 a symposium focusing on the current and future perspectives of baculovirus research was held in his honor at RIKEN and the resulting papers as well as a bibliography of his publications and several tributes are published in the RIKEN Review #22 (June, 1999). There is a great sadness that the University lost one of its brightest stars after little more than a decade. However, Susumu Maeda lived life to the fullest and shared much with his students and colleagues. We are fortunate that this wonderful scientist, mentor, colleague and friend shared this all too brief period with us.
"We understand death for the first time when he puts his hand upon one whom we love"--De Stael