title: Differential expression of extracellular thiol groups of moderately thermophilic Sulfobacillus thermosulfidooxidans and extremely thermophilic Acidianus manzaensis grown on S(0) and Fe (2.).
abstract: Bio-oxidation of elemental sulfur (S(0)) is very important in bioleaching and sulfur cycle. S(0) was proposed to be first activated by reacting with reactive thiol groups (-SH) of outer membrane proteins, forming -S n H (n ≥ 2) complexes. The differential expression of -SH of moderately thermophilic Sulfobacillus thermosulfidooxidans and extremely thermophilic Acidianus manzaensis grown on Fe(2+) and S(0) was investigated by synchrotron radiation-based scanning transmission X-ray microscopy (STXM) imaging and micro-beam X-ray fluorescence (μ-XRF) mapping. The STXM imaging and μ-XRF mapping of extracellular -SH were based on the analysis of Ca(2+) bound on the cell. By comparing Ca(2+) of the cells with and without labeling by Ca(2+), the distribution and content of thiol groups were obtained. The results showed that, for both S. thermosulfidooxidans and A. manzaensis, the expression of extracellular -SH of S(0)-grown cells was higher than that of Fe(2+)-grown cells. Statistical analysis indicated that the expression of extracellular -SH for S. thermosulfidooxidans and A. manzaensis grown on S(0) was 2.37 times and 2.14 times, respectively, to that on Fe(2+). These results evidently demonstrate that the extracellular thiol groups are most probably involved in elemental sulfur activation and oxidation of the acidophilic sulfur-oxidizing microorganisms.
authors.affiliation: School of Minerals Processing and Bioengineering, Central South University, Changsha, 410083, China.
authors.forename: Hong-Chang
authors.initials: HC
authors.lastname: Liu
authors.forename: Jin-Lan
authors.initials: JL
authors.lastname: Xia
authors.forename: Zhen-Yuan
authors.initials: ZY
authors.lastname: Nie
authors.forename: Xiang-Jun
authors.initials: XJ
authors.lastname: Zhen
authors.forename: Li-Juan
authors.initials: LJ
authors.lastname: Zhang
mesh_terms: D041541:Acidianus / Q000378:metabolism; D007501:Iron / Q000378:metabolism*; D010084:Oxidation-Reduction; D013438:Sulfhydryl Compounds / Q000378:metabolism*; D016943:Sulfolobaceae / Q000378:metabolism*; D013455:Sulfur / Q000378:metabolism*; D055114:X-Ray Microtomography
chemical_list: D013438:Sulfhydryl Compounds; D013455:Sulfur; D007501:Iron