News – Researchers in Japan have first observed biological magnetoreception – living, unchanged cells responding to a magnetic field in real time. This discovery is a crucial step in understanding how animals from birds to butterflies navigate using the Earth’s magnetic field and address the question of whether weak electromagnetic fields can occur in the environment. we have an impact on human health.
“The great thing about this research is that we see that the relationship between the spins of two separate electrons can have a major impact on biology,” said Professor Jonathan Woodward of the University of Tokyo, who conducted the research with doctoral student Noboru Ikeya The results were recently published in the Proceedings of the National Academy of Sciences United States of America (PNAS).
Researchers have been skeptical since the 1970s that because magnets can attract and replicate electricity, the Earth’s magnetic field, also known as the geomagnetic field, can affect the behavior of animals by affecting chemical reaction. When some molecules are exposed to light, an electron can jump from one molecule to another and form two molecules with one electron, called a radical pair. The single electrodes can be in one of two different spinning states. If both radicals have the same electron spin, their subsequent chemical reactions are slow, while radical pairs with opposite electron spins can react faster. Magnetic fields can affect electron spinning states and thus directly affect chemical reactions involving radical pairs.
Over the past 50 years, chemists have identified a number of specific reactions and proteins called cryptochromes that are sensitive to magnetic fields in test tube environments. Biologists have even seen how genetic predisposition by cryptochromes in fruit flies and cockroaches could destroy the ability of insects to navigate according to geomagnetic factors. Other research has shown that the geomagnetic direction of birds and other animals is sensitive to light. However, no one has previously measured chemical reactions inside a living cell changing directly due to a magnetic field.
Woodward and Ikeya worked with HeLa cells, human breast cancer cells commonly used in a research laboratory, and were particularly interested in their flavin molecules.
Flavins are a subunit of cryptochromes that are themselves a common and well-studied group of molecules that naturally glow, or bloom, when exposed to blue light. They are important molecules in biology.
When flavors are enlivened by light, they can flower or form radical pairs. This competition means that the amount of flavin fluorescence depends on how quickly the radical pairs react. The University of Tokyo team hoped to monitor biological magnetoreception by monitoring cell autofluorescence while adding an artificial magnetic field to their environment.
Autofluorescence is common in cells, so to separate flavin autofluorescence, the researchers used lasers to illuminate a specific wave of light on the cells and then measured the waves of light sent back by the cells to make sure that it matched the normal values of flavin autofluorescence. . Conventional magnetic equipment can generate heat, so the researchers took extensive measures and performed a complete control measurement to determine if the only change in the environment of the cells was the presence or absence of the magnetic field.
“My goal even as a Ph.D. student is to never see these radical pair effects in a real biological system. I think that’s what we’ve regulated , “said Woodward.
The cells were irradiated with blue light and incubated for about 40 seconds. Researchers sweep a magnetic field over the cells every four seconds and measure changes in the intensity of the fluorescence. Statistical analysis of the visual data from the experiments showed that the fluorescence of the cell decreased by about 3.5% each time the magnetic field swept over the cells.
The researchers suspect that the blue light destroys the flavin molecules to generate radical pairs. The presence of a magnetic field caused the same radical spinning states to have the same radical spinning states, resulting in fewer flavin molecules being available to emit light. Thus, the flavin fluorescence of the cell decreased until the magnetic field disappeared.
“We have not altered or added anything to these cells. We believe we have very strong evidence that we have observed a quantum mechanical process affecting chemical activity at the cellular level,” Woodward said. .
Real-world lab and magnetoreception tests
The experimental magnetic fields were 25 millitesla, which is roughly equivalent to common cooling magnets. The Earth’s magnetic field varies with location, but is estimated to be about 50 microtesla, or 500 times weaker than the magnetic fields used in the experiments.
Woodward argues that the Earth’s very weak magnetic field could have an important biological effect due to a phenomenon known as the low field effect. While strong magnetic fields make it difficult for radical pairs to move between states in which the two electron spins are the same and states in which they are different, weak magnetic fields can exert the opposite effect and reverse easier than when there is no magnetic field.
The authors are now studying the effect in other types of cells, the potential role of health and those around the cells, and testing candidates’ magnetic receptors, which insertion of cryptochromes directly inside cells. Explaining any possible environmental or physiological significance of the results requires the development of more specialized and highly sensitive equipment to work with much weaker magnetic fields and more detailed cellular analysis to answer them. which is sensitive to attach a magnetic field to specific signal paths or other outcomes within the cell.
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