Bacteria can also point north and south?!

Some creatures in nature seem to be born with navigation systems. For example, carrier pigeons can deliver letters over long distances without making mistakes, bees can find their way back to their hives even when wandering among flowers, and sharks can swim straight in the ocean for a long time and distance without getting lost. The secret is that the existence of the geomagnetic field is the basis of reality, and the key is their respective "navigational abilities".

Are there any microorganisms that know the way? The answer is yes, magnetotactic bacteria are one of them. After the end of World War II, the scientific and technological productivity of various countries developed rapidly, and the fields and contents of people's research were greatly expanded and deepened.

In the late 1950s, Italian Bellini first observed that some bacteria could sense the Earth's magnetic field. However, like many "first discoveries", this discovery did not attract much attention at the time. More than a decade later, American Richard P. Blakemore (bacteriologist) accidentally obtained several bacteria that could move along the magnetic field in marine mud and swamp sediments.

When he put them under a microscope, he found that these microorganisms always moved toward one end of the slide. Then, he had an idea and put a magnet next to the slide. As a result, an amazing scene appeared - these little things actually moved toward the north pole of the magnet! So far, magnetotactic bacteria have officially appeared on the stage, and Blakemore is also recognized as the discoverer of magnetotactic bacteria.

Magnetotactic bacteria is not actually the name of a certain type of bacteria, but a general term. Magnetotactic bacteria exist in bacilli, cocci, spirochetes and vibrio. Their commonalities are constantly being discovered by scientists, such as they are usually Gram-negative bacteria, have flagella on their bodies, have mobility, can obtain iron from the surrounding environment, and form magnetosomes (iron-containing, individual tiny magnetic particles, wrapped by proteins or phospholipids, etc., and have no cytotoxicity) in their bodies. Their distribution is also diverse, but they mainly exist in the ocean, lakes, riverbed mud, and soil.

Serially arranged magnetosomes

Readers who are good at thinking divergently may guess that Blakemore's experiment should have been conducted in the United States. Magnetotactic bacteria move toward the north pole of the magnet, which is the geomagnetic south pole (the North Pole of the Earth). So if this experiment was conducted somewhere in the southern hemisphere, how would the microorganisms move? If it was conducted near the equator, would the magnetotactic bacteria remain still or move toward one of the poles?

The answer to the above question has long been revealed. In the 1980s, American scientists conducted relevant research and found that there are indeed bacteria moving towards the geomagnetic north pole (the south pole of the earth) in the southern hemisphere, and bacteria moving in both directions coexist near the equator.

So why do magnetotactic bacteria have this orientation? From the perspective of "use it or lose it", magnetotactic bacteria, which are mostly anaerobic microorganisms, need such mobility to ensure their movement in environments such as water and silt (transfer to anoxic or anaerobic environments), and their practical basis is the magnetosomes mentioned above.

Each cell contains a number of magnetosomes (2-10, containing Fe3O4 and Fe3S4), which are uniform in size and prismatic (six-sided or eight-sided). Each magnetosome has north and south poles and is arranged in a linear chain inside the cell, allowing the bacteria to move along the geomagnetic field. In addition, studies have confirmed that the magnetotactic ability of magnetotactic bacteria is hereditary, and several magnetosome synthesis genes have been cloned.

Don't underestimate magnetosomes, they are star materials in the high-tech field. First of all, they are better than artificial products in terms of "workmanship" and material. Magnetosomes are fine and uniform, and are very ideal magnetic recording materials. They are ideal for manufacturing computer memory elements. Using their superparamagnetism, magnetic liquids with a wide range of uses can be produced. Using their high coercivity characteristics, high-density storage magnetic powder can be produced for the production of magnetic keys and magnetic cards.

Computer memory components

Secondly, it is highly bio-friendly. Magnetosomes are biological magnets with no cytotoxicity. They can be used and have been used as specific drug delivery carriers, and have extraordinary functions in the field of organ tissue treatment. In addition, magnetosomes can also be used as transgenic carriers for the manufacture of biosensors, etc.

Biosensors

I believe that as people continue to deepen their research on magnetotactic bacteria, discoveries and surprises will follow one after another, which will inevitably benefit mankind more and better.

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