Magnetotactic bacteria

About: Magnetotactic bacteria is a research topic. Over the lifetime, 1118 publications have been published within this topic receiving 43741 citations.

Continuous Cultivation and Recovery of Magnetotactic Bacteria

Abstract: Magnetotactic bacteria (MTB) may be manipulated by the application of magnetic fields. This effect enables motile, magnetic field susceptible MTB to be utilised in the removal of contaminants, such as heavy metals, from wastewater. This paper discusses a process designed for continuous cultivation and extraction of metal loaded MTB. The performance of this recovery system is characterized here with respect to bacterial motility, the number of passes through the separator and the processing rate.

Architecture of flagellar apparatus of marine magnetotactic cocci from Qingdao

Abstract: Magnetotactic bacteria can align and swim along the geomagnetic field lines.The motility is propelled by the rotation of semi-rigid flagellar filaments.In this study,we reported the motility and ultrastructure of marine magnetotactic cocci isolated from intertidal zone in Qingdao city.Results obtained by optical microscopy and transmission electron microscopy showed that these ovoid-shaped bacteria,QH-3,possessed two bundles of flagella.Each bundle with a diameter of about 62 nm ±9 nm consists of seven flagellar filaments enveloped in a sheath.The architecture of flagellar apparatus was similar to that of Mediterranean magneto-ovoid bacteria MO-1.However,QH-3 synthesized two chains of rectangular magnetosomes instead of one chain found in MO-1 cells.Such flagellar architecture has been reported only for some magnetotactic cocci.This observation suggests that the typical struc-ture of the flagellar apparatus may be required for the magnetotactic motility of this group of microbes.

Competitive and cooperative anisotropy in magnetic nanocrystal chains of magnetotactic bacteria

Abstract: The formation of cellular magnetic dipoles by chain assemblies of stable single-domain magnetite nanocrystals is a characteristic feature in magnetotactic bacteria (MTB). The dipole strength depends on the competition or cooperation between the various anisotropic energy contributions, mainly between the magnetocrystalline and the interaction-induced shape anisotropy. Ferromagnetic resonance spectroscopy and numerical simulations of intracellular magnetite assemblies in the MTB Desulfovibrio magneticus strain RS-1 show that the alignment of elongated nanocrystallites leads to a predominant uniaxial anisotropy, which is enhanced when the magnetocrystalline symmetry is collinear to the chain, i.e., the anisotropies are cooperative vs. being competitive. This direct insight into the anisotropy variations in chain assemblies provides a physical framework to tailor magnetic nanocomposites, where the collective magnetic properties result from the interactions between the individual nanocrystalline constituents.

Unexpected diversity of magnetococci in intertidal sediments of Xiaoshi Island in the North Yellow Sea

Abstract: Magnetotactic bacteria (MTB) are a group of prokaryotes that, despite their high morphological, phylogenetic, and ecological diversity, share a common capability of forming intracellular nanocrystals of magnetite (Fe3O4) or greigite (Fe3S4), called magnetosomes, and swimming along geomagnetic field lines in a process called magnetotaxis. In this study, we investigated the MTB diversity within the intertidal sediments near Xiaoshi Island (Weihai) in the North Yellow Sea using a combination of molecular ecology techniques and transmission electron microscopy (TEM). The combination of restriction fragment length polymorphism (RFLP) analysis and 16S rRNA gene sequencing revealed seven new MTB genera affiliated with the Alphaproteobacteria class. Fluorescence in situ hybridization (FISH) analyses suggested that one magnetotactic coccus (designated as WHI-2) is the dominant species. TEM observations and energy dispersive X-ray analyses revealed that MTB cells mainly form magnetite magnetosomes that are organized into two chains of magnetosomes composed of e-prismatic magnetite crystals. This finding suggests the adaptation of a magnetotactic bacterial population to the marine tide. This is the first report of magnetotactic bacteria near Xiaoshi Island, which should be useful for studies of biogeochemical cycling and the geohistory of this area.