Ferromagnetic resonance and magnetic characteristics of intact magnetosome chains in Magnetospirillum gryphiswaldense

Fischer, H.; Mastrogiacomo, Giovanni; Löffler, Jörg F.; Warthmann, R.; Weidler, Peter G.; Gehring, A. U.

doi:10.1016/j.epsl.2008.03.022

Cited by 77 publications

(124 citation statements)

References 52 publications

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“…in the X-band range [11,27,29,36]. S-band FMR spectroscopy operates with microwave frequencies in the 4 GHz range.…”

Section: Basic Principles and Simulationmentioning

confidence: 99%

“…Magnetotactic bacteria (MTB) and their chemically stable magnetic remains, known as magnetofossils, have attracted considerable interest as proxy to infer microbial ecology during the Earth's history [3][4][5][6][7]. Although the magnetic properties of MTB are well known [8][9][10][11][12][13], the detection of magnetofossils in geological samples remains ambiguous. The hallmark of MTB is to form intracellular ferrimagnetic particles encapsulated in membranes, termed magnetosomes.…”

Section: Introductionmentioning

confidence: 99%

“…asymmetry of the absorption spectra) permit a direct way to detect the anisotropy of magnetosome chains [11,[27][28][29][30][31][32]. Mastrogiacomo et al [33] showed that FMR experiments of MTB using microwave frequency of 4 GHz, i.e.…”

Section: Introductionmentioning

confidence: 99%

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S-band ferromagnetic resonance spectroscopy and the detection of magnetofossils

Gehring

Kind

Charilaou

et al. 2013

J. R. Soc. Interface.

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We report the use of S-band ferromagnetic resonance (FMR) spectroscopy to compare the anisotropic properties of magnetite particles in chains of cultured intact magnetotactic bacteria (MTB) between 300 and 15 K with those of sediment samples of Holocene age in order to infer the presence of magnetofossils and their preservation in a geological time frame. The spectrum of intact MTB at 300 K exhibits distinct uniaxial anisotropy because of the chain alignment of the cellular magnetite particles and their easy axes. This anisotropy becomes less pronounced upon cooling and below the Verwey transition (T V ) it is nearly vanished mainly owing to the change of direction of the easy axes. In a natural sample, magnetofossils were detected by uniaxial anisotropy traits similar to those obtained from cultured MTB above T V . Our comparative study emphasizes that indispensable information can be obtained from S-band FMR spectra, which offers even a better resolution than X-band FMR for discovering magnetofossils, and this in turn can contribute towards strengthening our relatively sparse database for deciphering the microbial ecology during the Earth's history.

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“…in the X-band range [11,27,29,36]. S-band FMR spectroscopy operates with microwave frequencies in the 4 GHz range.…”

Section: Basic Principles and Simulationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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S-band ferromagnetic resonance spectroscopy and the detection of magnetofossils

Gehring

Kind

Charilaou

et al. 2013

J. R. Soc. Interface.

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“…Thus far, EPR studies on the biogenic magnetic compounds have been limited in number. [19][20][21][22] Whitehead et al have reported that the biofilms from a river side showed an EPR signal originating from Fe-metabolizing bacteria. They identified the EPR spectra of ferrihydrite, hematite and magnetite.…”

Section: )mentioning

confidence: 99%

“…19) FMR (Ferromagnetic resonance) studies have also identified biogenic magnetite and ferrihydrite. [20][21][22] However, these studies were concerned only with the FMR of magnetite and ferrihydrite fractions, but not those of other cell fractions.…”

Section: )mentioning

confidence: 99%

A Ferromagnetic Resonance Study of Iron Complexes as Biologically Synthesized in Magnetic Bacteria

et al. 2009

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In order to analyze the magnetic behaviors of iron complexes biologically synthesized in magnetic bacteria MS-1, we performed FMR (Ferromagnetic Resonance) measurements for each fraction of the cell. We observed FMR spectra from the ferric iron (Fe 3þ ) compounds distributed in each fraction of the MS-1 cell. In particular, the magnetosome fraction yielded an anisotropic FMR signal, whereas other fractions were simple FMR spectra of a Gaussian type.Upon counting the numbers of spins in various cell fractions, we compared them with the iron population as determined by the 1.10-phenanthroline method. We found a good correlation between the number of spins and the iron population in several cell fractions. We concluded that the cell fractions, other than those fractions containing magnetite, consist mostly of ferric irons rather than ferrous irons.

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Low‐temperature magnetic properties of pelagic carbonates: Oxidation of biogenic magnetite and identification of magnetosome chains

et al. 2013

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[1] Pelagic marine carbonates provide important records of past environmental change. We carried out detailed low-temperature magnetic measurements on biogenic magnetite-bearing sediments from the Southern Ocean (Ocean Drilling Program (ODP) Holes 738B, 738C, 689D, and 690C) and on samples containing whole magnetotactic bacteria cells. We document a range of low-temperature magnetic properties, including reversible humped low-temperature cycling (LTC) curves. Different degrees of magnetite oxidation are considered to be responsible for the observed variable shapes of LTC curves. A dipole spring mechanism in magnetosome chains is introduced to explain reversible LTC curves. This dipole spring mechanism is proposed to result from the uniaxial anisotropy that originates from the chain arrangement of biogenic magnetite, similar to published results for uniaxial stable single domain (SD) particles. The dipole spring mechanism reversibly restores the remanence during warming in LTC measurements. This supports a previous idea that remanence of magnetosome chains is completely reversible during LTC experiments. We suggest that this magnetic fingerprint is a diagnostic indicator for intact magnetosome chains, although the presence of isolated uniaxial stable SD particles and magnetically interacting particles can complicate this test. Magnetic measurements through the Eocene section of ODP Hole 738B reveal an interval with distinct magnetic properties that we interpret to originate from less oxidized biogenic magnetite and enrichment of a biogenic "hard" component. Co-occurrence of these two magnetic fingerprints during the late Eocene in the Southern Ocean indicates less oxic conditions, probably due to increased oceanic primary productivity and organic carbon burial.

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Ferromagnetic resonance and magnetic characteristics of intact magnetosome chains in Magnetospirillum gryphiswaldense

Cited by 77 publications

References 52 publications

S-band ferromagnetic resonance spectroscopy and the detection of magnetofossils

S-band ferromagnetic resonance spectroscopy and the detection of magnetofossils

A Ferromagnetic Resonance Study of Iron Complexes as Biologically Synthesized in Magnetic Bacteria

Low‐temperature magnetic properties of pelagic carbonates: Oxidation of biogenic magnetite and identification of magnetosome chains

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