Biogeomagnetism Group, Paleomagnetism and Geochronology Laboratory, Key Laboratory of the Earth's Deep Interior, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China.
FEMS Microbiol Lett. 2010 Jan;302(1):85-92. doi: 10.1111/j.1574-6968.2009.01838.x. Epub 2009 Oct 28.
Magnetotactic bacteria (MTB), which can mineralize nanosized magnetite or greigite crystals within cells, play important roles in biogeochemical processes, for example iron and sulfur cycling, and depositional remanent magnetization acquisitions. Despite decades of research, the knowledge of MTB distribution and ecology is still limited. In the present study, we investigated the temporal variation of MTB communities in freshwater sediment microcosms based on 16S rRNA genes and unifrac analyses. Two microcosms (MY8 and MY11) collected from two separate sites in Lake Miyun (Beijing, China) were analyzed. The majority of retrieved sequences belonged to alphaproteobacterial magnetotactic cocci in both microcosms (representing 64.29% of clones from MY8 and 100% of clones from MY11), whereas so-called 'Magnetobacterium bavaricum'-like MTB affiliated within Nitrospira phylum were exclusively found in microcosm MY8. Over a 3-month period, the temporal variation of MTB communities was evident in both microcosms. In addition, the phylogenetic discrepancy of MTB communities between two microcosms is more prominent than that of the same microcosm at different times, implying adaptation of MTB phylogenetic lineages to specific microenvironments. Among the physical-chemical parameters measured, a strong correlation was shown between nitrate and the main genetic variability of MTB communities, indicating that nitrate may influence the occurrence of MTB phylogenetic lineages in natural environments.
趋磁细菌（MTB）可以在细胞内矿化纳米级磁铁矿或纤铁矿晶体，在生物地球化学过程中发挥着重要作用，例如铁和硫循环以及沉积剩磁获取。尽管经过几十年的研究，MTB 的分布和生态知识仍然有限。在本研究中，我们基于 16S rRNA 基因和 unifrac 分析，研究了淡水沉积物微宇宙中 MTB 群落的时间变化。从中国北京密云湖的两个不同地点采集了两个微宇宙（MY8 和 MY11）进行分析。在两个微宇宙中，大多数回收的序列都属于 alpha-proteobacterial 趋磁球菌（代表 MY8 中 64.29%的克隆和 MY11 中 100%的克隆），而在微宇宙 MY8 中仅发现了属于 Nitrospira 门的所谓“Magnetobacterium bavaricum”-样 MTB。在 3 个月的时间内，两个微宇宙中的 MTB 群落都发生了明显的时间变化。此外，两个微宇宙中 MTB 群落的系统发育差异比同一微宇宙在不同时间的差异更为明显，这表明 MTB 系统发育谱系适应特定的微环境。在所测量的理化参数中，硝酸盐与 MTB 群落的主要遗传变异性之间表现出强烈的相关性，表明硝酸盐可能影响 MTB 系统发育谱系在自然环境中的出现。
