TY  - JOUR
A1  - Günther, Erika
A1  - Klauß, André
A1  - Toro-Nahuelpan, Mauricio
A1  - Schüler, Dirk
A1  - Hille, Carsten
A1  - Faivre, Damien
T1  - The in vivo mechanics of the magnetotactic backbone as revealed by correlative FLIM-FRET and STED microscopy
JF  - Scientific reports
N2  - Protein interaction and protein imaging strongly benefit from the advancements in time-resolved and superresolution fluorescence microscopic techniques. However, the techniques were typically applied separately and ex vivo because of technical challenges and the absence of suitable fluorescent protein pairs. Here, we show correlative in vivo fluorescence lifetime imaging microscopy Forster resonance energy transfer (FLIM-FRET) and stimulated emission depletion (STED) microscopy to unravel protein mechanics and structure in living cells. We use magnetotactic bacteria as a model system where two proteins, MamJ and MamK, are used to assemble magnetic particles called magnetosomes. The filament polymerizes out of MamK and the magnetosomes are connected via the linker MamJ. Our system reveals that bacterial filamentous structures are more fragile than the connection of biomineralized particles to this filament. More importantly, we anticipate the technique to find wide applicability for the study and quantification of biological processes in living cells and at high resolution.
Y1  - 2019
U6  - https://doi.org/10.1038/s41598-019-55804-5
SN  - 2045-2322
VL  - 9
PB  - Nature Publ. Group
CY  - London
ER  - 
TY  - JOUR
A1  - Ghaisari, Sara
A1  - Winklhofer, Michael
A1  - Strauch, Peter
A1  - Klumpp, Stefan
A1  - Faivre, Damien
T1  - Magnetosome Organization in Magnetotactic Bacteria Unraveled by Ferromagnetic Resonance Spectroscopy
JF  - Biophysical journal
N2  - Magnetotactic bacteria form assemblies of magnetic nanoparticles called magnetosomes. These magnetosomes are typically arranged in chains, but other forms of assemblies such as clusters can be observed in some species and genetic mutants. As such, the bacteria have developed as a model for the understanding of how organization of particles can influence the magnetic properties. Here, we use ferromagnetic resonance spectroscopy to measure the magnetic anisotropies in different strains of Magnetosprillum gtyphiswaldense MSR-1, a bacterial species that is amendable to genetic mutations. We combine our experimental results with a model describing the spectra. The model includes chain imperfections and misalignments following a Fisher distribution function, in addition to the intrinsic magnetic properties of the magnetosomes. Therefore, by applying the model to analyze the ferromagnetic resonance data, the distribution of orientations in the bulk sample can be retrieved in addition to the average magnetosome arrangement. In this way, we quantitatively characterize the magnetosome arrangement in both wild-type cells and Delta mamJ mutants, which exhibit differing magnetosome organization.
Y1  - 2017
U6  - https://doi.org/10.1016/j.bpj.2017.06.031
SN  - 0006-3495
SN  - 1542-0086
VL  - 113
SP  - 637
EP  - 644
PB  - Cell Press
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Baumgartner, Jens
A1  - Lesevic, Paul
A1  - Kumari, Monika
A1  - Halbmair, Karin
A1  - Bennet, Mathieu
A1  - Koernig, Andre
A1  - Widdrat, Marc
A1  - Andert, Janet
A1  - Wollgarten, Markus
A1  - Bertinetti, Luca
A1  - Strauch, Peter
A1  - Hirt, Ann
A1  - Faivre, Damien
T1  - From magnetotactic bacteria to hollow spirilla-shaped silica containing a magnetic chain
JF  - RSC Advances
N2  - Magnetotactic bacteria produce chains of magnetite nanoparticles, which are called magnetosomes and are used for navigational purposes. We use these cells as a biological template to prepare a hollow hybrid material based on silica and magnetite, and show that the synthetic route is nondestructive as the material conserves the cell morphology as well as the alignment of the magnetic particles. The hybrid material can be resuspended in aqueous solution, and can be shown to orient itself in an external magnetic field. We anticipate that chemical modification of the silica can be used to functionalize the material surface in order to obtain multifunctional materials with specialized applications, e.g. targeted drug delivery.
Y1  - 2012
U6  - https://doi.org/10.1039/c2ra20911j
SN  - 2046-2069
VL  - 2
IS  - 21
SP  - 8007
EP  - 8009
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  -