|Lam, KP; Hitchcock, AP; Obst, M; Lawrence, JR; Swerhone, GDW; Leppard, GG; Tyliszczak, T; Karunakaran, C; Wang, J; Kaznatcheev, KV; Bazylinski, DA; Lins, U: Characterizing magnetism of individual magnetosomes by X-ray magnetic circular dichroism in a scanning transmission X-ray microscope, Chemical Geology, 270(1-4), 110-116 (2010), online: 22.11.2009, doi:10.1016/j.chemgeo.2009.11.009 [Link]|
Soft X-ray scanning transmission X-ray microscopy (STXM) was used to measure the Fe L2, 3 X-ray magnetic circular dichroism (XMCD) signal from individual, 30 nm diameter magnetosomes in a magnetotactic bacterium, specifically the marine vibrio strain MV-1. The Fe L2, 3 spectra recorded with circularly polarized X-rays from an elliptically polarizing undulator were very similar in shape and magnitude to those of fully saturated magnetite (Fe3O4). As previously determined by other techniques, our results show that the magnetic moments of individual magnetosomes arranged in linear chains in intact cells of strain MV-1 are all oriented in the same direction. The magnitude of the XMCD signal averaged over a chain of 9 magnetosomes in one cell is similar to that of single crystal magnetite. The spectral shape is slightly different, and indicates that magnetosomes have excess Fe(II), as noted in previous bulk studies of biogenic magnetite. To our knowledge, this is the first measurement of the XMCD of individual magnetosomes in magnetotactic bacteria.
|Do. 05.12.2019 aktuell|
Natürlich gegen Rechts? Von wegen!
Iron, sulfur and a pinch of antimony - new perspectives on secondary mineral pathways and metalloid mobility
Intensify or diversify? How agriculture affects biodiversity and ecosystem processes in European farmland
The meat of the Anthropocene: Food, capital and the globalisation of industrialised animal killing
Auf ins Neue! Winterspaziergang im ÖBG
Stoichiometric controls of C and N cycling
Flying halfway across the globe to dig in the dirt – a research stay in Bloomington, USA
EGU – interesting research and free coffee
Picky carnivorous plants?