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Clusters of superparamagnetic magnetite particles in the upper-beak skin of homing pigeons; evidence of a magnetoreceptor?

Michael Winklhofer, Elke Holtkamp-Roetzler, Marianne Hanzlik, Gera Fleissner and Nikolai Petersen
Clusters of superparamagnetic magnetite particles in the upper-beak skin of homing pigeons; evidence of a magnetoreceptor? (in Biogenic iron minerals, Mihaly Posfai (prefacer))
European Journal of Mineralogy (August 2001) 13 (4): 659-669

Abstract

Previous electrophysiological studies on bobolinks, an American migratory songbird, and on homing pigeons suggested that the skin of the upper beak may be involved in magnetic-field perception, which makes this tissue likely to contain a magnetic-field receptor. In the upper-beak skin of homing pigeons, we localised high concentrations of Fe (super 3+) , which form distinct coherent elongated structures extending up to 200 mu m in length. Rather than being randomly distributed over the tissue, these structures always occur in the same skin layer, the stratum laxum of the subcutis. Using transmission electron microscopy (TEM), we identified the material as aggregates of magnetite (Fe (sub 3) O (sub 4) ) nanocrystals, in the grain-size range of superparamagnetism at ambient temperatures. The nanocrystals (with grain-sizes between 2 and 5 nm) form densely packed, encapsulated clusters of 1 to 3 mu m in diameter. It is demonstrated that such a cluster undergoes shape changes as the magnetic field changes, and thus could represent the core of a magnetic-field receptor. This interpretation is supported by the fact that the found structures are adjacent to nervous material.


ISSN: 0935-1221
EISSN: 1617-4011
Serial Title: European Journal of Mineralogy
Serial Volume: 13
Serial Issue: 4
Title: Clusters of superparamagnetic magnetite particles in the upper-beak skin of homing pigeons; evidence of a magnetoreceptor?
Title: Biogenic iron minerals
Affiliation: Ludwig-Maximilians-Universitaet, Institut fuer Geophysik, Munich, Federal Republic of Germany
Affiliation: University of Veszprem, Hungary
Pages: 659-669
Published: 200108
Text Language: English
Publisher: Schweizerbart'sche Verlagsbuchhandlung (Naegele u. Obermiller), Stuttgart, Federal Republic of Germany
Meeting name: Biogenic iron minerals symposium and workshop
Meeting location: Tihany, HUN, Hungary
Meeting date: 20000520May 20-23, 2000
References: 43
Accession Number: 2001-065620
Categories: Mineralogy of non-silicates
Document Type: Serial Conference document
Bibliographic Level: Analytic
Illustration Description: illus.
Secondary Affiliation: Johann Wolfgang Goethe-Universitaet, DEU, Federal Republic of Germany
Country of Publication: Germany
Secondary Affiliation: GeoRef, Copyright 2020, American Geosciences Institute.
Update Code: 200120
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