HAL Id: jpa-00219576
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Submitted on 1 Jan 1980
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MAGNETOTAXIS IN BACTERIA
R. Frankel, R. Blakemore
To cite this version:
R. Frankel, R. Blakemore. MAGNETOTAXIS IN BACTERIA. Journal de Physique Colloques, 1980, 41 (C1), pp.C1-38-C1-38. �10.1051/jphyscol:1980106�. �jpa-00219576�
JOURNAL DE PHYSIQUE Colloque C l , suppfdment au no 1 , Tome 41, janvier 1980, page C1-38
MAGNETOTAXIS IN BACTERIA
R.B. Frankel and R.P. Blakemore +
Francis B i t t e r National Laboratory, MIT, Cambridge, MA 0 2 2 3 9 .
+ Dept. of Microbiologya Univ. of N e w Hampshire, Durham, NH 03824.
Magnetic bacteria that orient and sarim in a preferred direction in the earth's magne- tic field have been A previously undescribed magnetotactic spirillum isolated from a fresh water swamp was mass cultured in magnetic as well as non- magnetic state in chemically defined culture media. Magnetic bacteria contain opaque intracytoplasmic "crystallites" approx. 500
62
on a side that are rich in iron. 22-25 crystallites are arranged in a chain along the length of the spirillum. NSssbauer spectroscopy at room temperature of a sample of freeze dried magnetic cells reveal that the cryetallites are composed primarily of magnetite (Fe 0 The observed3 4
particle size is in the single domain range, and a chain of single domain particles will orient with their individual dipole moments along the chain, constituting a single magnetic dipole. The calculated moment.per bacterium is sufficient to produce alignment in the,geomagnetic field at ambient temperature. Thus the magnetite parti- cles consitute an internal compass4 for bacterial navigation. Magnetite has also been observed in other organisms596.
References
1. R.P.Blakemore, Science
190, 377
(1975) 2. Ad.J.Kalmijn and R.P.Blakemore, in AnimalMigration, Navigation and Aoming, Schmidt- Koenig and Keeton, eds.,(Springer Verlag, N.X., 1978).
3.
R.B.Franke1, et al. Science203,
1355 (1979) 4. R.B.Franke1 and R.P.B.Blakemore, Proc.Int.Coef-on Magnetism, Munich,l979
5. H.A.Lowenstam, Bull .Geol.Am.
22,
435 (1962) 6. J.L.Gould, et al. Science201,
1026 (1978).n Supported by the U.S.National Science Foundation.
Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1980106
