Pan Weidong, Chen Chuanfang, Wang Xiaoke, Ma Qiufeng, Jiang Wei, Lv Jing, Wu Long-Fei, Song Tao
Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing, China.
Bioelectromagnetics. 2010 Apr;31(3):246-51. doi: 10.1002/bem.20549.
Magnetotactic bacteria are a diverse group of microorganisms which possess one or more chains of magnetosomes and are endowed with the ability to use geomagnetic fields for direction sensing, thus providing a simple and excellent model for the study of magnetite-based magnetoreception. In this study, a 50 Hz, 2 mT pulsed magnetic field (PMF) was applied to study the effects on the formation of magnetosomes in Magnetospirillum sp. strain AMB-1. The results showed that the cellular magnetism (R(mag)) of AMB-1 culture significantly increased while the growth of cells remained unaffected after exposure. The number of magnetic particles per cell was enhanced by about 15% and slightly increased ratios of magnetic particles of superparamagnetic property (size <20 nm) and mature magnetosomes (size >50 nm) were observed after exposure to PMF. In addition, the intracellular iron accumulation slightly increased after PMF exposure. Therefore, it was concluded that 50 Hz, 2 mT PMF enhances the formation of magnetosomes in Magnetospirillum sp. strain AMB-1. Our results suggested that lower strength of PMF has no significant effects on the bacterial cell morphologies but could affect crystallization process of magnetosomes to some extent.
趋磁细菌是一类多样的微生物，它们拥有一条或多条磁小体链，并具有利用地磁场进行方向感知的能力，从而为基于磁铁矿的磁感受研究提供了一个简单而出色的模型。在本研究中，施加了50 Hz、2 mT的脉冲磁场（PMF）来研究其对趋磁螺菌AMB-1菌株磁小体形成的影响。结果表明，暴露后AMB-1培养物的细胞磁性（R(mag)）显著增加，而细胞生长未受影响。暴露于PMF后，每个细胞的磁性颗粒数量增加了约15%，并且观察到超顺磁性（尺寸<20 nm）和成熟磁小体（尺寸>50 nm）的磁性颗粒比例略有增加。此外，PMF暴露后细胞内铁积累略有增加。因此，得出结论：50 Hz、2 mT的PMF增强了趋磁螺菌AMB-1菌株中磁小体的形成。我们的结果表明，较低强度的PMF对细菌细胞形态没有显著影响，但可能在一定程度上影响磁小体的结晶过程。
