Magnetite magnetosome biomineralization in Magnetospirillum magneticum strain AMB-1: A time course study
Résumé
Magnetotactic bacteria are a highly studied group of diverse prokaryotes that 15 biomineralize chains of magnetosomes, single domain, single crystal magnetic nanoparticles of 16 magnetite or greigite, enclosed by a lipid bilayer membrane whose synthesis is under strict 17 control. In addition to characterizing the genetics and physicochemical properties of both 18 and uncultured environmental species, there have been a number of investigations using a time 19 course approach to determine the chemical pathway of magnetite biomineralization in these 20 organisms. In time course studies, cells of MTB are typically grown in the absence of iron so 21 cannot make magnetite, and then provided with iron in culture medium which initiates the 22 biomineralization of magnetosome chains over a subsequent time period. Results from previous 23 time course studies are not consistent with one another, differing with regard to the nature of 24 chemical intermediates and the rate of establishment of magnetosome chains. In this work we 25 report a time course study of Magnetospirillum magneticum strain AMB-1 over a 48 hour (h) 26 period, using transmission electron microscopy (TEM) and soft X-ray scanning transmission 27 X-ray microscopy (STXM) at the Fe Ledge. STXM provides capability to measure X-ray 28 absorption spectra (XAS) and map chemical species with ~25 nm spatial resolution and thus 29 detailed results on the chemistry of individual particles in single cells. An evolution of the iron 30 *Revised manuscript with no changes marked Click here to view linked References
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