title: Newly isolated but uncultivated magnetotactic bacterium of the phylum Nitrospirae from Beijing, China.
abstract: Magnetotactic bacteria (MTB) in the phylum Nitrospirae synthesize up to hundreds of intracellular bullet-shaped magnetite magnetosomes. In the present study, a watermelon-shaped magnetotactic bacterium (designated MWB-1) from Lake Beihai in Beijing, China, was characterized. This uncultivated microbe was identified as a member of the phylum Nitrospirae and represents a novel phylogenetic lineage with ≥6% 16S rRNA gene sequence divergence from all currently described MTB. MWB-1 contained 200 to 300 intracellular bullet-shaped magnetite magnetosomes and showed a helical swimming trajectory under homogeneous magnetic fields; its magnetotactic velocity decreased with increasing field strength, and vice versa. A robust phylogenetic framework for MWB-1 and all currently known MTB in the phylum Nitrospirae was constructed utilizing maximum-likelihood and Bayesian algorithms, which yielded strong evidence that the Nitrospirae MTB could be divided into four well-supported groups. Considering its population densities in sediment and its high numbers of magnetosomes, MWB-1 was estimated to account for more than 10% of the natural remanent magnetization of the surface sediment. Taken together, the results of this study suggest that MTB in the phylum Nitrospirae are more diverse than previously realized and can make important contributions to the sedimentary magnetization in particular environments.
authors: Biogeomagnetism Group, Paleomagnetism and Geochronology Laboratory, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China. weilin0408@gmail.com
authors: Wei
authors: W
authors: Lin
authors: Jinhua
authors: J
authors: Li
authors: Yongxin
authors: Y
authors: Pan
mesh_terms: D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D018407:Bacterial Physiological Phenomena; D002681:China; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D005618:Fresh Water / Q000382:microbiology*; D019015:Geologic Sediments / Q000382:microbiology*; D008124:Locomotion; D055944:Magnetosomes / Q000378:metabolism; D008853:Microscopy; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S