It has currently been recognised that reactive oxygen species (ROS) function as signalling molecule in a variety of organisms including bacteria, fungi, and animals. On the other hand, the regulation of ROS production and the mechanism for its coupling with ROS sensor molecules are not fully understood. In various eukaryotes including mammals, the regulation of ROS production involves the Nox family of NADPH oxidases, which deliberately produce ROS upon cell stimulation. Human genome contains seven Nox-encoding genes, which are expressed in a cell type-specific manner. However, it remains largely unknown about their regulation and function; for instance, the sub-cellular localisation of Nox oxidases, the mechanism underlying control of the localisation, and the regulatory mechanism of their ROS production at specific sites.
Also in microorganisms such as bacteria and yeasts, ROS and their related molecules participate in their responses to oxidative stress, but their molecular mechanisms remain to be elucidated. In this project, to understand “oxygen-dependent, ROS-mediated regulation of signal transduction”, we will focus on the following issues: (1) the spacio-temporal control of mammalian Nox-family oxidases; (2) regulation of Nox-coupled physiological functions in mammalian cells; (3) regulation of nitric oxide (NO) synthesis and its physiological role in the budding yeast Saccharomyces cerevisiae; and (4) control of sulfur oxide (SOx) production and its function in Escherichia coli. Our fundamental research also would greatly contribute to the development of new biotechnology based on microbial functions, such as breeding of useful microorganisms for alcoholic beverage brewing, bread making, and bioethanol and amino acid production.
Graduate School of Biological Sciences, Nara Institute of Science and Technology
1982 Awarded the degree of M.S., Nagoya University
1982 - 1995 Research Scientist at Ajinomoto Co., Inc.
(1986 Visiting Research Associate, State University of New York at Stony Brook)
(1988 Awarded the degree of Ph.D., The University of Tokyo)
1994 Chief Biochemist at Food Research & Development Laboratories, Ajinomoto Co., Inc.
1995 Associate Professor at Department of Bioscience, Fukui Prefectural University
2001 Professor at Department of Bioscience, Fukui Prefectural University
2006 - present Professor at Graduate School of Biological Sciences, Nara Institute of Science and Technology
Microbial cells are always exposed to the environment where oxygen concentration changes unlike multicellular organisms such as mammals and plants. The microbe acquires a system in response to a drastic environmental change in a process of the evolution, suggesting that there is the origin of various environmental responses by multicellular organisms to microorganisms. In this way, understanding of microbial functions and mechanisms for the environment where oxygen concentration changes is one of the most important research fields in terms of not only elucidation of microbial diversity but also finding a new working hypothesis or a hint of the solution for the complicated biological phenomenon in higher eukaryotes. We will explore original research with learning excellent mechanisms of microorganisms.