title: In situ analysis of sulfur in the sulfur globules of phototrophic sulfur bacteria by X-ray absorption near edge spectroscopy.
abstract: During the oxidation of sulfide and thiosulfate purple and green sulfur bacteria accumulate globules of 'elemental' sulfur. Although essential for a thorough understanding of sulfur metabolism in these organisms, the exact chemical nature of the stored sulfur is still unclear. We applied sulfur K-edge X-ray absorption near edge spectroscopy (XANES) to probe the forms of sulfur in intact cells. Comparing XANES spectra of Allochromatium vinosum, Thiocapsa roseopersicina, Marichromatium purpuratum, Halorhodospira halophila and Chlorobium vibrioforme grown photolithoautotrophically on sulfide with reference probes (fingerprint method), we found sulfur chains with the structure R-S(n)-R. Evidence for the presence of sulfur rings, polythionates and anionic polysulfides in the sulfur globules of these bacteria was not obtained.
authors.affiliation: Institut für Mikrobiologie & Biotechnologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Meckenheimer Allee 168, D-53115, Bonn, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Prange
authors.forename: I
authors.initials: I
authors.lastname: Arzberger
authors.forename: C
authors.initials: C
authors.lastname: Engemann
authors.forename: H
authors.initials: H
authors.lastname: Modrow
authors.forename: O
authors.initials: O
authors.lastname: Schumann
authors.forename: H G
authors.initials: HG
authors.lastname: Trüper
authors.forename: R
authors.initials: R
authors.lastname: Steudel
authors.forename: C
authors.initials: C
authors.lastname: Dahl
authors.forename: J
authors.initials: J
authors.lastname: Hormes
mesh_terms: D019414:Chlorobi / Q000737:chemistry*; D004577:Electron Probe Microanalysis; D005978:Glutathione / Q000032:analysis; D019803:Glutathione Disulfide / Q000032:analysis; D013057:Spectrum Analysis / Q000379:methods*; D013455:Sulfur / Q000032:analysis*
chemical_list: C056471:cyclooctasulfur; D013455:Sulfur; D005978:Glutathione; D019803:Glutathione Disulfide