Topic
Magnetotactic bacteria
About: Magnetotactic bacteria is a research topic. Over the lifetime, 1118 publications have been published within this topic receiving 43741 citations.
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01 Jan 2006
TL;DR: The ability of magnetotactic bacteria (MTB) to orient and migrate along magnetic field lines is basedon magnetosomes, which are membrane-enclosed intracellular crystals of a magnetic iron mineral.
Abstract: The ability of magnetotactic bacteria (MTB) to orient and migrate along magnetic field lines is basedon magnetosomes, which are membrane-enclosed intracellular crystals of a magnetic iron mineral. Thebiomineralization of magnetosomes is a process with genetic control over the accumulation of iron,the deposition of the magnetic crystal within a specific compartment, as well as their intracellularassembly and alignment into chain-like structures. Magnetite crystals produced by MTB have uniform species-specificmorphologies and sizes, which are mostly unknown from inorganic systems. In addition, magnetosome chainformation is an example of the highest structural level achievable in a prokaryotic cell. In thiswork, we give an overview of the biology of MTB and the structure and functions of bacterial magnetosomes.In addition we summarize the current knowledge of the physico-chemical and molecular genetic basis of magnetosomebiomineralization and chain formation.
9 citations
TL;DR: In this paper, the magnetization reversal of chains of 40-50 nanometer, magnetic particles has been studied using Magnetic Force Microscopy (MFM) in an applied field, stepwise increased and decreased in order to make hysteresis loops for the chains.
8 citations
Journal Article•
TL;DR: Intracellular iron accumulation studies on magnetotactic bacteria isolated from the Lonar lake in Maharashtra showed up to 11.5 times more iron than non-magnetic bacteria.
Abstract: Magnetotactic bacteria (MTB) are motile, aquatic prokaryotes that swim along geomagnetic field lines. These bacteria display a myriad of cellular morphologies, including coccoid, rod, vibrioid, spirilloid etc. with their unique 'magnetosomes' within the cells. The Lonar lake in Maharashtra, formed due to a meteorite impact crater, is a closed basin lake characterized by high alkalinity and salinity. The MTB isolated by the 'magnetic collection' and 'capillary racetrack' methods showed a typical response in the form of movement towards the magnet and precise alignment at the edge of the hanging drop. Intracellular iron accumulation studies on these bacteria showed up to 11.5 times more iron than non-magnetic bacteria.
8 citations
TL;DR: P pH in the magnetosomes within living magnetotactic bacterium Magnetospirillum magneticum AMB-1 cells is measured using the pH-sensitive fluorescent protein E2GFP to help for understanding magnetosome pH homeostasis and reveal molecular mechanisms of magnetite biomineralization in the bacterial organelle.
Abstract: Magnetotactic bacteria synthesize uniform-sized and regularly shaped magnetic nanoparticles in their organelles termed magnetosomes. Homeostasis of the magnetosome lumen must be maintained for its role accomplishment. Here, we developed a method to estimate the pH of a single living cell of the magnetotactic bacterium Magnetospirillum magneticum AMB-1 using a pH-sensitive fluorescent protein E2GFP. Using the pH measurement, we estimated that the cytoplasmic pH was approximately 7.6 and periplasmic pH was approximately 7.2. Moreover, we estimated pH in the magnetosome lumen and cytoplasmic surface using fusion proteins of E2GFP and magnetosome-associated proteins. The pH in the magnetosome lumen increased during the exponential growth phase when magnetotactic bacteria actively synthesize magnetite crystals, whereas pH at the magnetosome surface was not affected by the growth stage. This live-cell pH measurement method will help for understanding magnetosome pH homeostasis to reveal molecular mechanisms of magnetite biomineralization in the bacterial organelle.
8 citations