Polarity of bacterial magnetotaxis is controlled by aerotaxis through a common sensory pathway

Popp, Felix; Armitage, Judith P.; Schüler, Dirk

doi:10.1038/ncomms6398

Cited by 82 publications

(92 citation statements)

References 57 publications

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“…So far, little is known about the sensors and signals underlying magnetotaxis. One notable exception is the recent identification of an essential chemotaxis operon in M. gryphiswaldense [45]. The observation of poorer alignment with the external field in a mutant has also been interpreted to indicate a role for the deleted gene in sensing [38], but other interpretations remain possible, as discussed above.…”

Section: Modeling Magneto-aerotaxismentioning

confidence: 89%

“…A recent twist to this classical result is that the behavior of the Magnetospirilla upon field reversal is dependent on the conditions under which the culture has been grown. Grown under conditions closer to the natural ones, the magnetospirilla show a different behavior, namely polar magnetotaxis, discussed below, or a mixture of polar and axial magneto-aerotaxis [13,45].…”

Section: Magneto-aerotaxismentioning

confidence: 99%

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Magnetotactic bacteria

Klumpp

Faivre

2016

Eur. Phys. J. Spec. Top.

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Abstract. Magnetotactic bacteria are aquatic microorganisms with the ability to swim along the field lines of a magnetic field, which in their natural environment is provided by the magnetic field of the Earth. They do so with the help of specialized magnetic organelles called magnetosomes, vesicles containing magnetic crystals. Magnetosomes are aligned along cytoskeletal filaments to give linear structures that can function as intracellular compass needles. The predominant viewpoint is that the cells passively align with an external magnetic field, just like a macroscopic compass needle, but swim actively along the field lines, propelled by their flagella. In this minireview, we give an introduction to this intriguing bacterial behavior and discuss recent advances in understanding it, with a focus on the swimming directionality, which is not only affected by magnetic fields, but also by gradients of the oxygen concentration.

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Section: Modeling Magneto-aerotaxismentioning

confidence: 89%

Section: Magneto-aerotaxismentioning

confidence: 99%

Magnetotactic bacteria

Klumpp

Faivre

2016

Eur. Phys. J. Spec. Top.

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“…Recently, Popp and colleagues studied Magnetospirillum gryphiswaldense motility and showed that swimming polarity is controlled by aerotaxis in this magnetotactic bacterium (MTB) (8). Two simple models can explain how a symmetrical cell can swim in an oriented manner, and both imply that the two flagella are operated differently.…”

mentioning

confidence: 99%

Opposite and Coordinated Rotation of Amphitrichous Flagella Governs Oriented Swimming and Reversals in a Magnetotactic Spirillum

et al. 2015

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Current knowledge regarding the mechanism that governs flagellar motor rotation in response to environmental stimuli stems mainly from the study of monotrichous and peritrichous bacteria. Little is known about how two polar flagella, one at each cell pole of the so-called amphitrichous bacterium, are coordinated to steer the swimming. Here we fluorescently labeled the flagella of Magnetospirillum magneticum AMB-1 cells and took advantage of the magnetically controllable swimming of this bacterium to investigate flagellar rotation in moving cells. We identified three motility behaviors (runs, tumbles, and reversals) and two characteristic fluorescence patterns likely corresponding to flagella rotating in opposite directions. Each AMB-1 locomotion mode was systematically associated with particular flagellar patterns at the poles which led us to conclude that, while cell runs are allowed by the asymmetrical rotation of flagellar motors, their symmetrical rotation triggers cell tumbling. Our observations point toward a precise coordination of the two flagellar motors which can be temporarily unsynchronized during tumbling. IMPORTANCEMotility is essential for bacteria to search for optimal niches and survive. Many bacteria use one or several flagella to explore their environment. The mechanism by which bipolarly flagellated cells coordinate flagellar rotation is poorly understood. We took advantage of the genetic amenability and magnetically controlled swimming of the spirillum-shaped magnetotactic bacterium Magnetospirillum magneticum AMB-1 to correlate cell motion with flagellar rotation. We found that asymmetric rotation of the flagella (counterclockwise at the lagging pole and clockwise at the leading pole) enables cell runs whereas symmetric rotation triggers cell tumbling. Taking into consideration similar observations in spirochetes, bacteria possessing bipolar ribbons of periplasmic flagella, we propose a conserved motility paradigm for spirillum-shaped bipolarly flagellated bacteria. Mobile bacteria have developed strategies to efficiently explore their environment, in aqueous media as well as on solid surfaces (1, 2). In most cases, their movements are ensured by a highly efficient proteinaceous nanomachine, the flagellum. The flagellar apparatus comprises three main parts: the motor, the hook, and the flagellar filament. The flagellar motor, anchored in the plasma membrane, uses the proton motive force or the sodium ion gradient to power the rotation of the flagellar filament, which is connected to it through the structure called the hook (3, 4). The rotation of the motor determines the direction of flagellum rotation and, consequently, the swimming direction of the bacterium. Using that principle, chemotactic bacteria directly regulate motor rotation so as to swim toward an attractant or away from a repellent, which involves signal detection via chemoreceptors. The signal is then transmitted from the chemoreceptor to the flagellar motor through a phosphorylation-dephosphorylation cascade of dedica...

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“…Popp et al [81] showed that the deletion of one of the four chemotactic operons (CheOp1) led to the loss of swimming polarity in MSR-1. In order to study the magnetotactic behavior of wild-type (WT) and mutant bacteria, they recorded the swimming reversal and swimming speed of a suspension of bacteria in a gas perfusion chamber, following the hanging drop experiment preparation.…”

Section: Chemotactic Sensors In Msr-1mentioning

confidence: 99%