Professor Azuma Taoka from Faculty of Biological Science and Technology, Institute of Science and Engineering, Kanazawa University, Mizuki Fukui (at the time of the research) and Hitoki Shirakawa from Graduate from Division of Biological Science and Technology, Graduate School of Natural Science and Technology, Kanazawa University, in collaboration with a research group including Research Assistant Hirokazu Shimoshige from Bio-Nano Electronics Research Centre, Toyo University and Associate vice-Senior Staff Masayuki Miyazaki from Institute for Extra-cutting-edge Science and Technology Avant-garde Research (X-star), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), was the first in the world to successfully cultivate freshwater magnetotactic cocci (*1). Until now, freshwater magnetotactic cocci have been known as difficult-to-culture magnetotactic bacteria that are most commonly detected or observed in sediments in freshwater environments. The results of this research may help to elucidate the evolution of not only magnetotactic bacteria that inhabit various water environments on Earth, but all organisms that sense the geomagnetic field. It is also expected that a new mechanism for sensing the geomagnetic field by magnetosomes (*2) will be discovered.
Although freshwater magnetotactic cocci were discovered more than 40 years ago, there have been no successful cultures of freshwater magnetotactic cocci because they were extremely difficult to culture. In this study, we found a novel freshwater magnetotactic coccus FCR-1 containing unchained magnetosomes in the sediment of the Renju Dam on Chichijima Island in Ogasawara, Tokyo, and succeeded in culturing it for the first time in the world. This research was also the first in the world to cultivate magnetotactic bacteria containing unchained magnetosomes.
In this study, Professor Taoka and his colleagues contributed to the development of culture methods for the strain FCR-1 and the analysis of cell migration.
The results of this research were published in the international journal Communications Biology on March 27, 2025.
Figure 1: Magnetotactic cocci with chained magnetosomes
Figure 2: Freshwater magnetic coccus FCR-1 containing unchained magnetosomes
【Glossary】
*1: Magnetotactic cocci
Spherical magnetotactic bacteria. Magnetic bacteria are bacteria that synthesize nanometer (nm) sized (nm is 10 -9m) magnetic bodies (magnetic nanoparticles) composed of iron oxide or iron sulfide.
*2: Magnetosome
Intracellular organelles composed of magnetic nanoparticles covered with chained or unchained phospholipid bilayers
Click here to see the press release【Japanese only】
Journal：Communications Biology
Researcher's Information：Azuma Taoka
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