The most well‐recognized magnetoreception behaviour is that of the magnetotactic bacteria (MTB), which synthesize membrane‐bounded magnetic nanocrystals called magnetosomes via a biologically controlled process. The magnetic minerals identified in prokaryotic magnetosomes are magnetite (Fe₃O₄) and greigite (Fe₃S₄). Magnetosome crystals, regardless of composition, have consistent, species‐specific morphologies and single‐domain size range. Because of these features, magnetosome magnetite crystals possess specific properties in comparison to abiotic, chemically synthesized magnetite. Despite numerous discoveries regarding MTB phylogeny over the last decades, this diversity is still considered underestimated. Characterization of magnetotactic microorganisms is important as it might provide insights into the origin and establishment of magnetoreception in general, including eukaryotes. Here, we describe the magnetotactic behaviour and characterize the magnetosomes from a flagellated protist using culture‐independent methods. Results strongly suggest that, unlike previously described magnetotactic protists, this flagellate is capable of biomineralizing its own anisotropic magnetite magnetosomes, which are aligned in complex aggregations of multiple chains within the cell. This organism has a similar response to magnetic field inversions as MTB. Therefore, this eukaryotic species might represent an early origin of magnetoreception based on magnetite biomineralization. It should add to the definition of parameters and criteria to classify biogenic magnetite in the fossil record.

中文翻译：

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鞭毛状原生生物中的磁小体磁铁矿生物矿化：真核生物中磁感受的早期进化起源的证据

公认的磁感受行为是趋磁细菌（MTB）的行为，它通过生物控制的过程合成膜结合的磁性纳米晶体，称为磁小体。在原核磁小体中鉴定出的磁性矿物是磁铁矿（Fe ₃ O ₄）和钙铁矿（Fe ₃ S ₄）。磁小体晶体，无论其成分如何，都具有一致的，特定于物种的形态和单域大小范围。由于这些特征，与非生物化学合成的磁铁矿相比，磁小体磁铁矿晶体具有特定的特性。尽管在过去几十年中发现了许多有关MTB系统发育的发现，但仍认为这种多样性被低估了。趋磁微生物的表征很重要，因为它可能提供对包括真核生物在内的一般磁感受的起源和建立的见解。在这里，我们描述了趋磁行为，并使用与文化无关的方法来表征鞭毛原生生物的磁小体。结果强烈表明，与先前描述的趋磁生物不同，这种鞭毛能够生物矿化其自身的各向异性磁铁矿磁小体，它们在细胞内多条链的复杂聚集中排列。这种生物对磁场反转的响应与MTB相似。因此，这种真核生物可能代表了基于磁铁矿生物矿化的磁感受的早期起源。它应增加对参数和标准的定义，以便对化石记录中的生物磁铁矿进行分类。