Magnetosomes, magnetic nanoparticles (MNPs) encapsulated in lipid membranes produced by magnetotactic bacteria (MTB), have superior properties such as a narrow size distribution, making them of potential significant value for biomedical and industrial applications. However, the slow growth rate and genetic complexity of MTB have thus far limited large scale production of biologically synthesized MNPs. This problem is compounded by a lack of a platform to select MTB of interest. Here, the development of a magnetic ratcheting system that facilitates automated, live, and quantitative isolation of Magnetospirillum magneticum (AMB‐1) based on their phenotype, i.e., number of MNPs is described. Using repeated (five) cycles of random chemical mutagenesis and magnetic selection, AMB‐1 overproducers that biomineralize on average 2.2‐fold more MNPs (≈25) than the widely available strain AMB‐1 are generated. The size, shape, and magnetic properties of the MNPs of the overproducers are also similar to the control AMB‐1, supporting the utility of the platform for enriching MTB with overproducer phenotypes.

中文翻译：

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使用磁性棘轮系统对磁性磁螺线菌（AMB-1）生产过量的表型进行选择

磁小体是封装在由趋磁细菌（MTB）产生的脂质膜中的磁性纳米颗粒（MNP），具有优越的性能，例如狭窄的尺寸分布，使其在生物医学和工业应用中具有潜在的重要价值。但是，MTB的缓慢生长速度和遗传复杂性迄今限制了生物合成MNP的大规模生产。缺乏选择感兴趣的MTB的平台使这个问题更加复杂。在这里，开发了一种磁性棘轮系统，该系统有助于自动，实时和定量地分离磁链霉菌（AMB-1）基于它们的表型，即描述了MNP的数量。使用随机化学诱变和磁性选择的重复（五个）循环，生物矿化的AMB-1过生产者平均比广泛使用的菌株AMB-1多2.2倍的MNP（≈25）。过量生产者的MNP的大小，形状和磁性也类似于对照AMB-1，从而支持该平台的实用性，可以利用过量生产者表型来丰富MTB。