Magnetotactic bacteria

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

Highest levels of Cu, Mn and Co doped into nanomagnetic magnetosomes through optimized biomineralisation

Abstract: Magnetotactic bacteria synthesize pure morphologically precise nano-magnetite crystals called magnetosomes. Doping magnetosomes varies their magnetic properties, making them very promising nanomaterials. Here we present the highest doping of Co2+ (3.0%), Mn2+ (2.7%) and Cu2+ (15.6%) into magnetosomes in vivo. Most significantly, the first report of Cu-doping in magnetite magnetosomes and the highest metal doped into magnetosomes recorded. A 2-fold increase is recorded for Mn and Co doping over previous reports.

Bioinspired Magnetite Mineralization of Peptide−Amphiphile Nanofibers

Abstract: Peptide−amphiphile nanofibers displaying iron-binding sequences were used as templates to control the growth and organization of magnetite (Fe3O4) nanocrystals into linear arrays, mimicking aspects of the linear arrangement of magnetite crystals along a filamentous structure in magnetotactic bacteria.

Characterization of Bacterial Magnetotactic Behaviors by Using a Magnetospectrophotometry Assay

Abstract: Magnetotactic bacteria have the unique capacity of synthesizing intracellular single-domain magnetic particles called magnetosomes. The magnetosomes are usually organized in a chain that allows the bacteria to align and swim along geomagnetic field lines, a behavior called magnetotaxis. Two mechanisms of magnetotaxis have been described. Axial magnetotactic cells swim in both directions along magnetic field lines. In contrast, polar magnetotactic cells swim either parallel to the geomagnetic field lines toward the North Pole (north seeking) or antiparallel toward the South Pole (south seeking). In this study, we used a magnetospectrophotometry (MSP) assay to characterize both the axial magnetotaxis of “Magnetospirillum magneticum” strain AMB-1 and the polar magnetotaxis of magneto-ovoid strain MO-1. Two pairs of Helmholtz coils were mounted onto the cuvette holder of a common laboratory spectrophotometer to generate two mutually perpendicular homogeneous magnetic fields parallel or perpendicular to the light beam. The application of magnetic fields allowed measurements of the change in light scattering resulting from cell alignment in a magnetic field or in absorbance due to bacteria swimming across the light beam. Our results showed that MSP is a powerful tool for the determination of bacterial magnetism and the analysis of alignment and swimming of magnetotactic bacteria in magnetic fields. Moreover, this assay allowed us to characterize south-seeking derivatives and non-magnetosome-bearing strains obtained from north-seeking MO-1 cultures. Our results suggest that oxygen is a determinant factor that controls magnetotactic behavior.

Using the magnetosome to model effective gene-based contrast for magnetic resonance imaging.

Abstract: Formation of iron biominerals is a naturally occurring phenomenon, particularly among magnetotactic bacteria which produce magnetite (Fe(3) O(4) ) in a subcellular compartment termed the magnetosome. Under the control of numerous genes, the magnetosome serves as a model upon which to (1) develop gene-based contrast in mammalian cells and (2) provide a mechanism for reporter gene expression in magnetic resonance imaging (MRI). There are two main components to the magnetosome: the biomineral and the lipid bilayer that surrounds it. Both are essential for magnetotaxis in a variety of magnetotactic bacteria, but nonessential for cell survival. Through comparative genome analysis, a subset of genes characteristic of the magnetotactic phenotype has been found both within and outside a magnetosome genomic island. The functions of magnetosome-associated proteins reflect the complex nature of this intracellular structure and include vesicle formation, cytoskeletal attachment, iron transport, and crystallization. Examination of magnetosome genes and structure indicates a protein-directed and stepwise assembly of the magnetosome compartment. Attachment of magnetosomes along a cytoskeletal filament aligns the magnetic particles such that the cell may be propelled along an external magnetic field. Interest in this form of magnetotaxis has prompted research in several areas of medicine, including magnetotactic bacterial targeting of tumors, MR-guided movement of magnetosome-bearing cells through vessels and molecular imaging of mammalian cells using MRI, and its hybrid modalities. The potential adaptation of magnetosome genes for noninvasive medical imaging provides new opportunities for development of reporter gene expression for MRI.

High Diversity of Magnetotactic Deltaproteobacteria in a Freshwater Niche

Abstract: Knowledge of the diversity of magnetotactic bacteria in natural environments is crucial for understanding their contribution to various biological and geological processes. Here we report a high diversity of magnetotactic bacteria in a freshwater site. Ten out of 18 operational taxonomic units (OTUs) were affiliated with the Deltaproteobacteria. Some rod-shaped bacteria simultaneously synthesized greigite and magnetite magnetosomes.