Sub-micrometer-scale mapping of magnetite crystals and sulfur globules in magnetotactic bacteria using confocal Raman micro-spectrometry.

ABSTRACT: The ferrimagnetic mineral magnetite Fe3O4 is biomineralized by magnetotactic microorganisms and a diverse range of animals. Here we demonstrate that confocal Raman microscopy can be used to visualize chains of magnetite crystals in magnetotactic bacteria, even though magnetite is a poor Raman scatterer and in bacteria occurs in typical grain sizes of only 35-120 nm, well below the diffraction-limited optical resolution. When using long integration times together with low laser power (<0.25 mW) to prevent laser induced damage of magnetite, we can identify and map magnetite by its characteristic Raman spectrum (303, 535, 665 cm(-1)) against a large autofluorescence background in our natural magnetotactic bacteria samples. While greigite (cubic Fe3S4; Raman lines of 253 and 351 cm(-1)) is oft

SUBMITTER: Eder SH 

PROVIDER: S-EPMC4169400 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature