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New research by scientists at the National Physical Laboratory (NPL) and the Universities of Manchester and Leicester suggests that the animal world’s ability to sense a magnetic field may be more widespread than previously thought.
The paper, published in Nature today (22 February), makes significant advances in our understanding of how animals’ sense and respond to magnetic fields in their environment. This new knowledge could also enable the development of novel measurement tools where the activity of biological cells - including potentially those in humans - can be selectively stimulated using magnetic fields.
Many animals use the Earth’s magnetic field for navigation and this so-called sixth sense has intrigued the biological community for many years. Magnetic fields are difficult to detect, however, because they carry very little energy. To overcome this challenge, nature has exploited quantum physics and Cryptochrome – a light-sensitive protein found in animals.
Dr Alex Jones, Principal Research Scientist in Biometrology at NPL said: “The absorption of light by a molecule bound to Cryptochrome - Flavin Adenine Dinucleotide (FAD) - results in movement of an electron within the protein. Due to quantum physics, this generates an active form of Cryptochrome that occupies one of two states.”
“The presence of a magnetic field impacts the relative populations of the two states, which in turn influences the active-lifetime of this protein.”
This change in lifetime sends a signal to the animal telling it about the magnetic field in its environment. In this study it has been proven, for the first time, that FAD - which is present in all living cells, including humans - alone can impart magnetic sensitivity if it is present sufficient quantities.
Dr. Adam Bradlaugh, a neuroscientist from The University of Manchester and the paper’s first author said that the work reveals “that a basic molecule, present in all cells can, at high enough amounts, impart magnetic sensitivity without any part of Cryptochromes being present.”
The magnetic field effects on FAD in the absence of Cryptochrome provide a clue as to the evolutionary origins of magnetoreception. It seems likely that Cryptochrome has evolved to utilize magnetic field effects on this ubiquitous and biologically ancient metabolite.
Professor Richard Baines, Neuroscientist, The University of Manchester said: “How we sense the external world, from vision, hearing through to touch taste and smell, are well understood. But by contrast, which animals can sense and how they respond to a magnetic field remains unknown. This study has made significant advances in understanding how animals sense and respond to external magnetic fields - a very active and disputed field.”
In addition to shedding light on the natural mechanism of animal magnetoreception, this work raises the possibility that magnetic fields could be used to selectively stimulate cellular processes, with potential biomedical applications.
Professor Ezio Rosato, The University of Leicester said: “because FAD and other components of these molecular machines are found in many cells, this new understanding may also open new avenues of research into using magnetic fields to manipulate the activation of target genes. That is considered a holy-grail as an experimental tool and possibly eventually for clinical use.”
22 Feb 2023