A comparative study of magnetic properties between whole cells and isolated magnetosomes of Magnetospirillum magneticum AMB-1
A comparative study of magnetic properties between whole cells and isolated magnetosomes of Magnetospirillum magneticum AMB-1
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DOI：
10.1007/s11434-009-0333-x
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发表时间：
2010
影响因子：
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通讯作者：
Jinhua Li;Yongxin Pan;Qingsong Liu;H. Qin;C. Deng;R. Che;Xin’an Yang
中科院分区：
文献类型：
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作者：
Jinhua Li;Yongxin Pan;Qingsong Liu;H. Qin;C. Deng;R. Che;Xin’an Yang
由于磁小体是自然残余磁化和古环境的潜在载体，以及生物技术和生物医学应用中的新型纳米生物材料，因此磁小体的磁性具有跨学科的兴趣。我们对新鲜的magnetospirillum magneticumAMB-1全细胞和分离的磁小体进行了磁显微镜和电子透射显微镜分析。结果表明，AMB-1合成了单域磁铁矿磁小体，它们以线性片段链的形式排列。两种样品磁性能的显著差异可以从磁小体的空间排列和静磁相互作用方面得到忠实的解释。对于整个细胞而言，强链内相互作用和弱链间相互作用产生非相互作用的单轴单畴粒子行为。其δ-比值为3.0，通过莫斯科维茨检验。相比之下，孤立磁小体样品的矫顽力值和δ-比（1.5）降低，这是由于三维静磁相互作用的增加和磁小体链的坍塌。这些观测结果为生物成因磁铁矿（磁小体）在磁性纳米材料中的应用和磁化石在古磁学和环境磁学中的应用提供了有益的见解。
The magnetic properties of magnetosome magnetite are of interdisciplinary interest because magnetosomes are potential carriers of natural remanent magnetization and paleoenvironment, as well as novel nano-biomaterials in biotechnological and biomedical applications. We carried out magnetic and electron transmission microscopy analyses of freshMagnetospirillum magneticumAMB-1 whole cells and isolated magnetosomes. Results revealed that AMB-1 synthesized single-domain magnetite magnetosomes, which are arranged in the form of linear fragmental chain. The distinct differences of magnetic properties between these two samples can be faithfully interpreted in terms of spatial arrangement of magnetosomes and magnetostatic interaction. For the whole cells, the strong intra-chain interactions and weak inter-chain interactions generate behaviors of non-interacting uniaxial single-domain particles. Itsδ-ratio is 3.0 and passes the Moskowitz test. In contrast, the isolated magnetosome sample has reduced values of coercivity andδ-ratio (1.5), due to increasing three-dimensional magnetostatic interactions and collapse of magnetosome chains. These observations provide useful insights into applications of the biogenic magnetite (magnetosomes) in magnetic nano-materials and magnetofossils in the paleomagnetic and environmental magnetism.