Magnetite biomineralization and geomagnetic sensitivity in higher animals: An update and recommendations for future study

Abstract

Magnetite, the only known biogenic material with ferromagnetic properties, has been identified as a biochemical precipitate in three of the five kingdoms of living organisms, with a fossil record that now extends back nearly 2 billion years. In the magnetotactic bacteria, protoctists, and fish, single-domain crystals of magnetite are arranged in membrane-bound linear structures called magnetosomes, which function as biological bar magnets. Magnetosomes in all three of these groups bear an overall structural similarity to each other, which includes alignment of the individual crystallographic [111] directions parallel to the long axis. Although the magnetosomes represent only a small volume fraction in higher organisms, enough of these highly energetic structures are present to provide sensitivity to extremely small fluctuations and gradients in the background geomagnetic field. Previous experiments with elasmobranch fish are reexamined to test the hypothesis that gradients played a role in their successful geomagnetic conditioning, and a variety of four-turn coil designs are considered that could be used to test the various hypotheses proposed for them.

Magnetoreception in eusocial insects: an update

“…It is postulated that the sensor is composed of magnetic nanoparticles, possibly magnetite, housed in a specialized organ that is coupled to mechanosensitive structures so as to transmit information from the geomagnetic field in the form of a torque or force to the nervous system as an electric signal. Based on this hypothesis, several models for transduction have been put forward for SD magnetite chains from early (Yorke 1979) to more recent models (Walker 2008) and for other magnetic particle systems (Presti & Pettigrew 1980;Kirschvink 1989;Sakaki et al 1990;Edmonds 1992Edmonds , 1996Shcherbakov & Winklhofer 1999;Davila et al 2003Davila et al , 2005.…”

Earthquake Prediction by Animals: Evolution and Sensory Perception

“…Primitive, early eukaryotes presumably inherited their magnetite-based magnetotactic responses from their bacterial ancestors, maintaining its use for providing a constant rudder against the randomizing influence Brownian motion (Torres de Araujo et al, 1985). The presence of nearly identical magnetosome-chain structures in higher animals, and their use in geomagnetic orientation, is most easily explained as the result of common descent (Chang and Kirschvink, 1989;Kirschvink, 1989). However, as the musculature and locomotor abilities improved in primitive animals, there would be selection for more accurate homing and orientation abilities.…”

Magnetite in human tissues: A mechanism for the biological effects of weak ELF magnetic fields

“…More extensivc discussions of this subject are provided by Kirschvink [1989] and in the volume edited by . Kirschvink, Jones, and MacFadden [ 19851.…”

“…Inorganic magnetites are usually small octahedral crystals, often with lattice dislocations and other crystal defects. The elongation of biogenic crystals in the ( 1 113 direction serves to maximize the net magnetic moment of the particle, and presumably is the result of natural selection for their magnetic properties [Kirschvink, 1989;Vali and Kirschvink, 1990;Kirschvink, I992aI. Second, bacterial magnetite crystals are restricted to a size range from 30 to about 500 nm, with shapes which confine them to the single-domain magnetic stability field [Butler and Banerjee, 19751.…”