济南冬季泉水水系中趋磁细菌的多样性

Diversity of Magnetotactic Bacteria in Jinan Spring Water System in Winter

为探究济南冬季泉水水系中细菌的生态分布、未培养趋磁细菌及其磁小体形态的多样性,选择济南市泉水源头、护城河及泉水汇集的大明湖等8处不同位点,于2018年1月13日收集水底表层泥样,富集环境中趋磁细菌,提取样品总DNA,进行16S r DNA高通量测序及生物信息学分析,并利用透射电子显微镜观察和统计趋磁细菌及磁小体的形态,揭示济南泉水水系中趋磁细菌的分布特征。结果表明,济南冬季泉水水系中趋磁细菌分布明显不均,泉水源头处未检测到趋磁细菌;黑虎泉下游护城河中发现了少量单链趋磁球菌,基因序列表明为新种,暂定为η-变形菌纲(Candidatus Etaproteobacteria)的一个菌株;众泉汇集的大明湖中趋磁细菌种类最多,且细菌和磁小体形态多样性复杂。微生物多样性分析发现,冬季泉水水系中细菌种类主要是变形菌门(Proteobacteria)、蓝细菌门(Cyanobacteria)和绿弯菌门(Chloroflexi),三者总丰度均占细菌总量的65%以上,具有磁细菌生长所需的群落环境。本研究可为深入研究未培养趋磁细菌的全基因组及可培养条件等提供素材与线索。

In order to explore the ecological distribution of bacteria,the diversity of uncultured magnetotactic bacteria( MTB) and their magnetosome morphology in Jinan spring water system in winter,the water sludge samples were collected from 8 sites in the fountainhead,mead stream Hucheng River and downstream Daming Lake on January 13,2018. The MTB cells were gathered from the sludge samples and used to extract the genome DNA for high-throughput sequencing and bioinformatics analysis. The morphology of MTB and magnetosome were observed by transmission electron microscope,and the distribution features of MTB in Jinan spring water in winter were revaled. The results showed that the distribution of MTB in Jinan spring water system was obviously uneven. No MTB was detected at the fountainheads. A small amount of single-stranded magnetococci was found in the downstream of Heihu Spring,which is a strain of Candidatus Etaproteobacteria.Daming Lake had the most diverse types of magnetotactic bacteria,and the morphology of bacteria and magnetosomes was diverse. Microbial diversity analysis showed that the types of bacteria in the spring water system in winter were mainly Proteobacteria,Cyanobacteria and Chloroflexi,whose abundance was more than 65%. The results in this article would provide materials and clues for the further researches of the whole genome and cultured conditions.