Magnetotactic bacteria

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

The Effect of Magnetotactic Bacteria on the Magnetic Properties of Marine Sediments

Abstract: Magnetotactic bacteria have been studied in three distinct sedimentary marine environments: a hypersaline lagoon, an intertidal CO3 marsh, and an open ocean basin. The bacteria and the ultra-fine grained, single domain magnetite (Fe3O4) they produce were extracted from the sediments and studied with transmission electron microscopy. Magnetic properties of the sediments were measured by rock magnetic techniques using a SQUID magnetometer. Our results show that magnetotactic bacteria contribute a significant fraction of the natural remanent magnetization to their sedimentary environment and in some cases may be the sole source of the stable remanence carrying mineral. The occurrence and abundance of these bacteria in a diversity of marine environments implies that they may also play a role in the microbial iron cycle.

Shaping Magnetite with Poly-l-arginine and pH: From Small Single Crystals to Large Mesocrystals.

Abstract: Control over particle size, size distribution, and colloidal stability are central aims in producing functional nanomaterials. Recently, biomimetic approaches have been successfully used to enhance control over properties in the synthesis of those materials. Magnetotactic bacteria produce protein-stabilized magnetite away from its thermodynamic equilibrium structure. Mimicking the bacteria's proteins using poly-l-arginine we show that by simply increasing the pH, the dimensions of magnetite increase and a single- to mesocrystal transformation is induced. Using synchrotron X-ray diffraction and transmission electron microscopy, we show that magnetite nanoparticles with narrow size distributions and average diameters of 10 ± 2 nm for pH 9, 20 ± 2 nm for pH 10, and up to 40 ± 4 nm for pH 11 can be synthesized. We thus selectively produce superparamagnetic and stable single-domain particles merely by controlling the pH. Remarkably, while an increase in pH brings about a thermodynamically driven decrease in size for magnetite without additives, this dependency on pH is inverted when poly-l-arginine is present.

Identification and characterization of magnetotactic Gammaproteobacteria from a salt evaporation pool, Bohai Bay, China.

Abstract: Magnetotactic bacteria (MTB) are phylogenetically diverse prokaryotes that can produce intracellular chain-assembled nanocrystals of magnetite (Fe3 O4 ) or greigite (Fe3 S4 ). Compared with their wide distribution in the Alpha-, Eta- and Delta-proteobacteria classes, few MTB strains have been identified in the Gammaproteobacteria class, resulting in limited knowledge of bacterial diversity and magnetosome biomineralization within this phylogenetic branch. Here, we identify two magnetotactic Gammaproteobacteria strains (tentatively named FZSR-1 and FZSR-2 respectively) from a salt evaporation pool in Bohai Bay, at the Fuzhou saltern, Dalian City, eastern China. Phylogenetic analysis indicates that strain FZSR-2 is the same species as strains SHHR-1 and SS-5, which were discovered previously from brackish and hypersaline environments respectively. Strain FZSR-1 represents a novel species. Compared with strains FZSR-2, SHHR-1 and SS-5 in which magnetite particles are assembled into a single chain, FZSR-1 cells form relatively narrower magnetite nanoparticles that are often organized into double chains. We find a good relationship between magnetite morphology within strains FZSR-2, SHHR-1 and SS-5 and the salinity of the environment in which they live. This study expands the bacterial diversity of magnetotactic Gammaproteobacteria and provides new insights into magnetosome biomineralization within magnetotactic Gammaproteobacteria.

Magnetotactic Bacteria and their Application in Medicine

Abstract: It is a known fact how the magnetic field of the Earth is very important for life. Relation between living systems and the earth magnetic field has been investigated for many years. Birds and their migration routes are the first one of the things that comes to mind when we state living things. The Earth’s magnetic field is still accepted to be the main factor for birds and other flying living beings to complete their travels correctly. The changes in migration routes, which are observed from time to time, are sometimes said to be due to the changes in the magnetic field. However, no light has been shed to this matter yet. The Earth’s magnetic field has not been sufficiently studied, and its role on small living models such as bacteria has not been adequately discussed. One of the best examples in this field is relation between the Earth’s magnetic field and “magnetotactic bacteria (MTB)”, which were discovered by Salvatore Bellini in 1963. Currently, it is claimed that magnetotactic bacteria have a widespread use in microbiology, mineralogy, limnology, physics, biophysics, chemistry, biochemistry, geology, crystallography, and astrobiology. Although the importance of this issue magnetic bacteria is still limitedly used in medical area. Therefore more performance is necessary to explore world of this bacteria that is candidate for new therapy strategies in the medical field. Because of the reason stated here and to attract the attention of scientists to this topic this short review has been prepared.