Toshio Hayakawa

Distribution and Identification of Airborne Fungi in Railway Stations in Tokyo, Japan

Distribution and Identification of Airborne Fungi in Railway Stations in Tokyo, Japan: Tamami Kawasaki, et al. Environmental Biotechnology Laboratory, Railway Technical Research Institute

Evaluation of mutagenicity and co-mutagenicity of strong static magnetic fields up to 13 Tesla in Escherichia coli deficient in superoxide dismutase.

To evaluate the biological effects of static magnetic fields (SMFs) up to 13 Tesla (T), with respect to superoxide behavior, by determining the effect on mutagenicity in superoxide dismutase (SOD)‐deficient Escherichia coli strain QC774, and its parental strain GC4468.

Effects of Static Magnetic Field on Mutagenesis in in vitro

Effects of static magnetic field up to 13 T were estimated in Escherichia coli and Saccharomyces cerevisiae. We observed that exposure to a 5 T static magnetic field resulted in a slight but significant increase in gene recombination frequency while frequency of reverse point mutation was not altered in S. cerevisiae. This mutagenic effect showed a dose response relationship as J-shape. To investigate an involvement of reactive oxygen species in possible mutagenic effect of static magnetic field, SOD deficient E. coli QC774 was used in thymine synthesis-based mutation assay. The result shows that static magnetic field up to 13 T did not indicate mutagenicity. Thus, it is suggested that frequency of point mutation does not changed under static magnetic field regardless of its susceptibility to superoxide. These results suggest that strong static magnetic field would have small but detectable mutagenic potential. Although mechanism of the mutagenic effect of static magnetic field has not been elucidated yet, the extent of this effect is estimated extremely small by comparison with other mutagens such as ultraviolet irradiation.