Transmission electron microscopy reveals a linear chain of tiny particles -- in black -- inside the cell. The particles are magnetic crystals with a diameter of 40 nanometers, which are arranged to form a linear "compass needle." Photo by Frank Müller/University of Bayreuth

July 31 (UPI) -- New research has revealed the mechanics of a magnetic bacteria named Magnetospirillum gryphiswaldense.

The unique species synchronizes its locomotion with the Earth's magnetic field using a chain of spiral-shaped magnetic crystals called magnetosomes.


According to a new study conducted by researchers in Germany, published this week in the journal Nature Microbiology, the formation of the magnetic chain is controlled by a protein named MamY.

Dozens of animals use Earth's magnetic field for navigational purposes, but scientists still don't understand exactly how this unique sensory ability works. Now, researchers have at least partially explained the mechanics of magnetic navigation in a unicellular bacteria species.

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Inside Magnetospirillum gryphiswaldense, dozens of magnetic crystals are attached to a thread-like structure, which prevents them from clumping together, pulled together by their magnetism. Forced to remain in a straight line, the chain aligns with the lines of Earth's magnetic field.

Like a compass needle, the phenomenon helps the bacteria travel in a straight line, allowing it to reach its preferred habitat, water-logged sediments, more quickly.

What scientists hadn't been able to figure out is why the chain evolved to form a straight line while the bacteria's cell shape assumed a spiral-like shape.

Using super-resolution microscopy, cryo-electron tomography and several other advanced imaging techniques, they found that the structural protein MamY ensures the chain maintains a straight line. The protein also positions the chain so that it can best accommodate the bacteria's swimming locomotion.

When scientists blocked the production of MamY in Magnetospirillum gryphiswaldense, each cell's magnetite crystals formed a chain but failed to maintain a straight line. The compass needle wobbled as the cells swam, reducing the efficiency of their movements.

"All these observations confirm the conclusion: MamY is the key protein that arranges the magnetosome chain in the cell in such a way that the function of a compass needle is perfectly fulfilled," lead study author Frank Müller, microbiologist at the University of Bayreut, said in a news release. "The protein enables the bacteria to navigate optimally."

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Researchers determined that MamY also helps anchor the compass-like chain to the most curved portion of the cell wall, ensuring the cell's locomotion is as uninhibited and as efficient as possible.