Intracellular Distribution of Iron in the Cell of Magnetotactic Bacteria Inhibited the Biosynthesis of Magnetic Nano-Particles by Limiting the Iron Source

Abstract:

Magnetotactic bacteria are the bacteria which synthesize nano-sized magnetic particles within their cell body. In the present study, the cells of a magnetotactic bacteria M. magnetotacticum MS-1 was fractionated and the iron amount of the cell fractions were measured. In order to study the relationship between the process of the biosynthesis of magnetosome and the intracellular transport of iron, MS-1 cells were cultured under iron limited culture conditions and the amount of iron in the cell fractions were compared with those under optimal culture conditions. The whole amount of iron was measured colorimetrically. To estimate the number of ferric ion, the number of spin was determined from the ESR spectrum. The cell fractions obtained after removing magnetosome (non-magnetic fractions) contained 30-40 % of the total iron in the intact cells. There was a good correlation between the number of spin and the iron amount of non-magnetic fractions under optimal culture conditions. Under iron limited conditions, the iron amount decreased not only in the fraction containing magnetosome but also in the non-magnetic fractions. The number of spin in the soluble fraction decreased remarkably. So, the correlation between the number of spin and the amount of iron was not observed under iron limited conditions. These results imply that the ratio of ferrous ion to whole amount of iron increased in the non-magnetic fractions under iron limited conditions as compared with that under optimal conditions.

• Periodical: Advanced Materials Research (Volumes 476-478)
• Pages: 1020-1026
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.476-478.1020
• Online since: February 2012
• Authors: Shingo Watanabe, Tatsuo Iwasa
• Keywords: Electron Spin Resonance, Magnetotactic Bacteria, Nano-Sized Magnetic Particle

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