Magnetically induced behaviour of ferritin corpuscles in avian ears: can cuticulosomes function as magnetosomes?

Abstract

Magnetoreception is an enigmatic, poorly understood sensory ability, described mainly on the basis of behavioural studies in animals of diverse taxa. Recently, corpuscles containing superparamagnetic iron-storage protein ferritin were found in the inner ear hair cells of birds, a predominantly single ferritin corpuscle per cell. It was suggested that these corpuscles might represent magnetosomes and function as magnetosensors. Here we determine ferritin low-field paramagnetic susceptibility to estimate its magnetically induced intracellular behaviour. Physical simulations show that ferritin corpuscles cannot be deformed or rotate in weak geomagnetic fields, and thus cannot provide magnetoreception via deformation of the cuticular plate. Furthermore, we reached an alternative hypothesis that ferritin corpuscle in avian ears may function as an intracellular electromagnetic oscillator. Such an oscillator would generate additional cellular electric potential related to normal cell conditions. Though the phenomenon seems to be weak, this effect deserves further analyses.

Magnetic particle-mediated magnetoreception

“…Although the location of these iron-rich organelles partly coincides with the region of interest indicated by neuronal expression experiments, selected area electron diffraction of the 'cuticulosome' produces patterns that are consistent with the mineral ferrihydrite, a mineral that exhibits only weak magnetic properties (but see [106]). However, its discovery has generated interest in exploring magnetoreception mechanisms beyond traditional torque-based MPM systems [107].…”

The cuticular plate: A riddle, wrapped in a mystery, inside a hair cell

“…Interestingly, birds have an enigmatic iron‐rich organelle called the cuticulosome within the cuticular plate of both their auditory and vestibular hair cells, which is thought to either store excess iron, stabilize the stereocilia, or mediate magnetic detection (Lauwers et al, ). It has also been proposed that the cuticulosome may function as an intracellular electromagnetic oscillator, which serves to generate additional cellular electric potential (Jandacka et al, ). This organelle appears to be conserved across avian species but is not found in mammals.…”

Physiological origin of biogenic magnetic nanoparticles in health and disease: from bacteria to humans

“…Furthermore, there is an alternative hypothesis that ferritin molecules in the avian ear may function as intracellular electromagnetic oscillators, generating additional electrical fields with an amplitude of ~0.1 pV in receptor cells and consequently auditory neurons. 229 However, we think that a voltage of 0.1 pV is too low to produce any significant biological effect, since the working membrane voltages are of the order of dozens of millivolts. There is also a hypothesis that BMNP chains represent nanoscale high-gradient magnetic separators of cluster components (eg, vesicles, granules, cells) in organisms.…”

“…Controlled application of weak static magnetic fields may cause rotation of SD magnetite, which may result in the opening of ionic membrane channels, modulation of the transmembrane potential, and/or generation of action potentials in neurons. 48,228 Simulations performed by Jandacka et al 229 show that SPM ferritin molecules cannot be deformed or rotated in weak geomagnetic fields, and thus cannot be involved in magnetoreception by deformation. Furthermore, there is an alternative hypothesis that ferritin molecules in the avian ear may function as intracellular electromagnetic oscillators, generating additional electrical fields with an amplitude of ~0.1 pV in receptor cells and consequently auditory neurons.…”

“…There is also a hypothesis that BMNP chains represent nanoscale high-gradient magnetic separators of cluster components (eg, vesicles, granules, cells) in organisms. [229][230][231] We hope that further development of physical methods for the discrimination of the core minerals in ferritin in physiological fluids and/or tissue will provide powerful tools to fight neurodegenerative disorders. In this regard, we think that the magnetism of the ferritin core may be a useful prognostic indicator, especially in some neurodegenerative diseases.…”