Magnetotactic bacteria

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

Magnetotactic Bacteria - A Natural Architecture Leading from Structure to Possible Applications

Abstract: Magnetotactic bacteria are aquatic micro-organisms which have the specific capacity to navigate along the lines of the earth's magnetic field. This property is related to the formation of chains of magnetic crystals called magnetosomes. All magnetotactic bacteria synthesize nano-sized intracellular magnetosomes that are surrounded by ultra-thin bio-membranes. The magnetosome chains serve as compass for navigation of the magnetotactic bacteria, and the cell flagella are considered as the mechanism for propelling the bacteria forward. This presentation describes various functions of the architectured structure of magnetotactic bacteria as well as their possible applications in biotechnology.

On the motion of magnetotactic bacteria: theoretical predictions and experimental observations.

Abstract: The movement of magnetotactic bacteria is done in a viscous media in the low Reynolds number regime. In the present research, the simple model for magnetotactic bacteria motion, proposed by Nogueira and Lins de Barros (Eur Biophys J 24:13–21, 1995), was used to numerically simulate their trajectory. The model was done considering a spherical bacterium with a single flagellum and a magnetic moment positioned in the sphere center and parallel to the flagella. The numerical solution shows that the trajectory is a cylindrical helix and that the body Euler angles have linear dependencies on time. Using that information, analytical expressions were obtained for the first time for the center-of-mass coordinates, showing that the trajectories are helixes oriented to the magnetic field direction. They also show that the magnetic moment does not align to the magnetic field, but it precesses around it, being fully oriented only for very high magnetic fields. The analytical solution obtained permits to relate for the first time the flagellar force to the axial velocity and helical radius. Trajectories of uncultivated magnetotactic bacteria were registered in video and the coordinates were obtained for several bacteria in different magnetic fields. The trajectories showed to be a complex mixture of two oscillating functions: one with frequency lower than 5 Hz and the other one with frequency higher than 10 Hz. The simple model of Nogueira and Lins de Barros shows to be incomplete, because is unable to explain the trajectories composed of two oscillating functions observed in uncultivated magnetotactic bacteria.

Device of separating and collecting magnetotactic bacteria and magnetosomes

Abstract: The utility model relates to a device of separating and collecting magnetotactic bacteria and magnetosomes A feed inlet is arranged at the upper end of the device, a discharge port is arranged at the bottom of the device, stirring equipment is further arranged at the bottom of the device, a collecting plate for collecting thallus and magnetosomes is arranged on the inner side wall of the device, magnetic filed generators are symmetrically arranged on the outer side wall, and an ultrasonic probe is arranged in the position of the feed inlet Under a state of not starting ultrasonic waves, culture liquor containing magnetotactic bacteria can adsorb thallus to the collecting plate in the stirring process by means of a magnetic field effect Once ultrasonic waves are started, thallus of magnetotactic bacteria can be ultrasonically crushed to separate magnetosomes and thallus Under the effect of an externally applied magnetic field, magnetosomes are adsorbed to the collecting plate, so that the magnetosomes are collected The device is simple in structure, low in cost and convenient to use, and provides the optimal means for advanced research on separation of magnetotactic bacteria and magnetosomes

MR imaging of Fe-Co nanoparticles, magnetotactic bacteria and Fe3O4 microparticles for future drug delivery applications

Abstract: Magnetic resonance imaging characteristics of novel potential drug delivery agents are investigated. Candidate carriers considered in this study are iron-cobalt (Fe-Co) nanoparticles, magnetotactic bacteria (MTB), and magnetite (Fe3O4) microparticles. The micro and nanoparticles are highly magnetic and can be steered using gradient coils. MTB, on the other hand, are microorganisms that naturally follow the magnetic field lines through a mechanism called magnetotaxis. These carriers share the capability to be controlled by magnetic field and to be detected on MR images.

High volume magnetite (Fe3O4) crystals from magnetotactic bacteria

Abstract: Magnetotactic bacteria presenting chains with high volume magnetite magnetosomes were studied by transmission electron microscopy. As a comparison other magnetotactic bacteria presenting smaller magnetosomes were also studied. The average lengths of the high volume and smaller crystals were 118 and 110 nm with standard deviations of 35 and 23 respectively and the average widths were 107 and 68 nm with standard deviations of 30 and 14 respectively. The High resolution transmission electron microscopy indicated that in both cases the long axis of the crystals coincide with the crystallographic [111] direction. The groupings of high volume magnetosomes did not lose their disposition in chains after treatment form their isolation from the bacteria while the smaller magnetosomes coiled