- Scientists suspect that quantum effects are behind the animals’ ability to perform geomagnetic navigation.
- It is believed that geomagnetic navigation is based on light.
- The researchers observe that the quantum changes induced by the magnets affect the luminescence of the cells.
We know at this point that there are species that can navigate using the earth’s magnetic field. Birds use this ability in their long-distance migrations, and the list of such species continues to grow, now including mole rats, turtles, lobsters, and even dogs. But exactly How? ‘Or’ What they may do so remains unclear.
Scientists have for the first time observed changes in magnetism causing a biomechanical response in cells. And if that’s not cool enough, the cells involved in the research were human cells, which supports theories that we ourselves might have what it takes to move around using the planet’s magnetic field. .
The research is published in PNAS.
Credit: © Xu Tao, CC BY-SA
The phenomenon observed by scientists at the University of Tokyo matched the predictions of a theory put forward in 1975 by Klaus Schulten of the Max Planck Institute. Schulten proposed the mechanism by which even a very weak magnetic field, like that of our planet, could influence chemical reactions in their cells, allowing birds to perceive magnetic lines and navigate as they seem to.
Shulten’s idea was about radical pairs. A radical is an atom or molecule with at least one unpaired electron. When two of these electrons belonging to different molecules become entangled, they form a radical pair. Since there is no physical connection between the electrons, their short-lived relationship belongs to the realm of quantum mechanics.
However brief their association is, it is long enough to affect the chemical reactions of their molecules. Entangled electrons can either spin exactly in sync with each other or exactly opposite each other. In the first case, the chemical reactions are slow. In the latter case, they are faster.
Credit: © Ikeya and Woodward, CC BY, originally published in PNAS DOI: 10.1073/pnas.2018043118
Previous research has revealed that some animal cells contain cryptochromes, proteins that are sensitive to magnetic fields. There is a subset of these called “flavins”, molecules that glow or autofluorescent when exposed to blue light. The researchers worked with human HeLa cells (human cervical cancer cells) because they are rich in flavins. This makes them particularly interesting because it appears that geomagnetic navigation is sensitive to light.
When hit with blue light, the flavins either glow or produce radical pairs – what happens is a balancing act in which the slower the rotation of the pairs, the fewer molecules are unoccupied and available for the fluorescence.
For the experiment, HeLa cells were irradiated with blue light for about 40 seconds, causing them to fluoresce. The researchers’ expectations were that this fluorescent light would result in the generation of radical pairs.
Since magnetism can affect the spin of electrons, every four seconds the scientists swept a magnet over the cells. They observed that their fluorescence decreased by about 3.5% each time they did, as shown in the image at the beginning of this article.
Their interpretation is that the presence of the magnet caused the electrons in the radical pairs to align, slowing the chemical reactions in the cell, so there were fewer molecules available to produce the fluorescence.
The short version: The magnet caused a quantum shift in the radical pairs that suppressed the flavin’s ability to fluoresce.
Jonathan Woodward, from the University of Tokyo, author of the study with doctoral student Noboru Ikeya, explains what is so exciting about this experience:
“What’s joyful about this research is seeing that the relationship between the spins of two individual electrons can have a major effect on biology.”
He notes, “We haven’t changed or added anything to these cells. We believe we have extremely strong evidence that we observed a purely quantum mechanical process affecting chemical activity at the cellular level.