School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China.
J Microbiol Methods. 2013 Sep;94(3):257-61. doi: 10.1016/j.mimet.2013.06.030. Epub 2013 Jul 10.
The differential expression of extracellular thiol groups by Acidithiobacillus ferrooxidans grown on substrates Fe(2+) and S(0) was investigated by using synchrotron radiation based scanning transmission X-ray microscopy (STXM) imaging and microbeam X-ray fluorescence (μ-XRF) mapping. The extracellular thiol groups (SH) were first alkylated by iodoacetic acid forming Protein-SCH2COOH and then the P-SCH2COOH was marked by calcium ions forming P-SCH2COOCa. The STXM imaging and μ-XRF mapping of SH were based on analysis of SCH2COO-bonded Ca(2+). The results indicated that the thiol group content of A. ferrooxidans grown on S(0) is 3.88 times to that on Fe(2+). Combined with selective labeling of SH by Ca(2+), the STXM imaging and μ-XRF mapping provided an in situ and rapid analysis of differential expression of extracellular thiol groups.
采用同步辐射扫描透射 X 射线显微镜（STXM）成像和微束 X 射线荧光（μ-XRF）映射技术，研究了嗜酸氧化亚铁硫杆菌在 Fe（2+）和 S（0）两种基质上生长时细胞外巯基基团的差异表达。首先通过碘乙酸将细胞外巯基基团（SH）烷基化，形成蛋白-SCH2COOH，然后用钙离子标记 P-SCH2COOH，形成 P-SCH2COOCa。基于 SCH2COO 结合的 Ca（2+）分析，对 SH 进行 STXM 成像和 μ-XRF 映射。结果表明，嗜酸氧化亚铁硫杆菌在 S（0）上生长时的巯基含量是在 Fe（2+）上生长时的 3.88 倍。结合 Ca（2+）对 SH 的选择性标记，STXM 成像和 μ-XRF 映射提供了细胞外巯基差异表达的原位和快速分析。
