The ability to sense Earth's magnetic field has evolved in various taxa. However, despite great efforts to find the 'magnetic-sensor' in vertebrates, the results of these scientific efforts remain inconclusive. A few decades ago, it was found that bacteria, known as magnetotactic bacteria (MTB), can move along a magnetic field using nanometric chain-like structures. Still, it is not fully clear...

A previously undescribed magnetotactic spirillum isolated from a freshwater swamp was mass cultured in the magnetic as well as the nonmagnetic state in chemically defined culture media. Results of Mossbauer spectroscopic analysis applied to whole cells identifies magnetite as a constituent of these magnetic bacteria.

Magnetotactic bacteria (MTB) represent a diverse collection of motile prokaryotes that biomineralize intracellular, membrane-bounded, tens-of-nanometer-sized crystals of a magnetic mineral called magnetosomes. Magnetosome minerals consist of either magnetite (Fe3O4) or greigite (Fe3S4) and cause cells to align along the Earth's geomagnetic field lines as they swim, a trait called magnetotaxis. ...

This paper reports on the magnetic properties of magnetosomes in the freshwater magnetotactic bacterium Aquaspirillum nlllgnetOlaClicwn. The magnetosomes are well crystallized particles of magnetite with dimensions of 40 to 50 nm, which are arranged within cells in a single linear chain and are within the single-magnetic-domain (SO) size range for. magnetite. A variety of magnetic properties ha...

Current NDT techniques are capable of identifying sub millimetre defects in structural materials. Nanoscale NDT however, necessitates development of new techniques for identifying and sizing surface and more importantly subsurface imperfections. The reliability of micro and especially nano scale components heavily depends on such new developments. This paper presents an attempt to explore the p...

Diffusive motions of the magnetosomes (enveloped Fe3O4 particles) in the magnetotactic bacterium Aquaspirillum magnetotacticum result in a very broad-line Mössbauer spectrum (T approximately 100 mm/s) above freezing temperatures. The line width increases with increasing temperature. The data are analyzed using a bounded diffusion model to yield the rotational and translational motions of the ma...

Magnetotactic bacteria (MTB) biomineralize intracellular membrane-bound crystals of magnetite (Fe3O4) or greigite (Fe3S4), and are abundant in the suboxic to anoxic zones of stratified marine environments worldwide. Their population densities (up to 10 cells ml−1) and high intracellular iron content suggest a potentially significant role in iron cycling, but very little is known about their pop...

The racetrack-based PCR approach is widely used in phylogenetic analysis of magnetotactic bacteria (MTB), which are isolated from environmental samples using the capillary racetrack method. To evaluate whether the capillary racetrack-based enrichment can truly reflect the diversity of MTB in the targeted environmental sample, phylogenetic diversity studies of MTB enriched from the Miyun lake ne...

[1] Ferromagnetic resonance spectroscopy (FMR) can be used to measure the effective magnetic field within a sample, including the contributions of both magnetic anisotropy and magnetostatic interactions. One particular use is in the detection of magnetite produced by magnetotactic bacteria. These bacteria produce single-domain particles with narrow size and shape distributions that are often el...

Purpose: Superparamagnetic iron oxide (SPIO) contrast agents have been used for a number of years to label cells for tracking by MRI. However, these particles are significantly disadvantaged in longitudinal imaging because, as cells divide, the amount of iron per cell decreases and eventually the labeled cells can no longer be detected. MR reporter genes exist that allow cells to produce iron p...