微生物的趋磁性与磁小体的生物矿化

Magnetotaxis and Magnetosome Biomineralization in Microorganisms

起源于地核的地磁场保护地表的生物圈、水圈和大气圈.许多生物能够利用地磁场进行定向和迁徙,称为生物感磁或生物趋磁性.趋磁细菌是一类能够进行趋磁运动的微生物,它们在细胞内矿化合成纳米尺寸、粒度均一、结晶良好、化学纯度高的Fe3O4或Fe3S4成分的磁小体颗粒,不仅是研究生物趋磁性起源、演化和机制的模式生物类群,也是地质微生物、生物地磁学和生物矿化的重要研究对象.从趋磁细菌的群落多样性和地理分布研究出发,在介绍新技术和新方法的基础上,着重论述这类微生物的趋磁性起源、磁小体生物矿化机理及其地质环境功能等,并对未来的研究和突破方向做了展望.

Many organisms, including microbes, insects, fish, birds and mammals, sense and use Earth＇s magnetic field for orientation and navigation, a physiological trait known as magnetoreception or magnetotaxis. Magnetotactic bacteria（MTB） biomineralize intracellular chain（s） of membrane-bounded, nano-sized magnetosome crystals of either magnetite（Fe3 O4） or greigite（Fe3 S4） for magnetotaxis. So far, magnetosomes in MTB are the only magnetoreceptor that have been characterized and are therefore the model system with which the origin and evolution of magnetotaxis as well as microbial biomineralization can be explored. MTB also plays important roles in the geochemical cycling of iron, sulfur, nitrogen and carbon. Here we review recent contributions to the fields of diversity, biogeography, origin, magnetotaxis, biomineralization mechanisms and environmental function of MTB. Novel technologies including metagenomics, single-cell genomics and nanoscale secondary ion mass spectrometry（NanoSIMS） that have recently been successfully applied to the research of MTB are also summarized.